The problems of tailings storage and high-stress conditions in deep mining have emerged as critical factors that limit the security,efficiency,and sustainability of such mines.This study explores the potential to util...The problems of tailings storage and high-stress conditions in deep mining have emerged as critical factors that limit the security,efficiency,and sustainability of such mines.This study explores the potential to utilize tungsten tailings to create cementitious backfill(CTB)materials and investigates the macroscopic strength features and microscopic damage evolution mechanisms of different-sized CTBs with varying dosages of hydroxypropyl methyl cellulose(HPMC).Specimens with bottom diameters of 50,75,and 100 mm are combined with HPMC dosages of 0,0.15wt%,0.25wt%,and 0.35wt%.A diameter/height ratio of 1:2 is maintained for all CTB specimens.The experimental results show that as the HPMC dosage is increased from 0 to 0.35wt%,the uniaxial compressive strength(UCS)of the CTBs decreases significantly in a linear manner.The 75 mm×150 mm CTB specimen exhibits relatively high plasticity and toughness,with good plastic deformation and energy absorption capabilities,indicating significant size effects.HPMC introduces connected bubbles during the CTB pouring process,but it exhibits anti-segregation and anti-bleeding characteristics,thus reducing tailing settling.The hydration reaction of the CTB doped with HPMC is more uniform,and the Ca/Si atomic ratio dispersion at different sites is smaller.The three CTB sizes all exhibit combined tensile and shear failure,with the 75 mm×150 mm specimen exhibiting macroscopic tensile cracks and relatively few shear cracks.At the micro-scale,excessive ettringite and hydrated calcium silicate are interwoven and fuse,and the tungsten tailings are tightly wrapped.These results provide valuable data and notional insights for optimizing the fluidity of the backfill,and elucidate the strength and damage evolution of solidified materials during filling and extraction.This study contributes to the advancement of green,economical,safe,and sustainable mining practices.展开更多
Soil-bentonite(SB)backfills in vertical cutoff walls are used extensively to contain contaminated groundwater.Previous studies show that the hydraulic conductivity of backfill can exceed the typically recommended maxi...Soil-bentonite(SB)backfills in vertical cutoff walls are used extensively to contain contaminated groundwater.Previous studies show that the hydraulic conductivity of backfill can exceed the typically recommended maximum value(k=1×10^(−9) m/s)if exposed to groundwater impacted by organic acids commonly released from uncontrolled landfills and municipal solid waste dumps.Polymer amended backfills exhibit excellent chemical compatibility to metal-laden groundwater.However,few studies to date have explored the effect of organic acid contaminated groundwater on hydraulic performance of polymer amended backfills.This study presents an experimental investigation on the hydraulic performance and microstructural properties of a composite polymer amended backfill used to contain flow of acetic acid-laden groundwater.A series of laboratory experiments were performed to evaluate free-swell indices of the composite polymer amended bentonites,liquid limits of the composite polymer amended and unamended bentonites,and slump heights and hydraulic conductivity(k)values of the amended backfills to acetic acid solutions with varying concentrations.The results were compared with those of the unamended bentonites and unamended backfills reported in a previous study.The results showed that the free-swell index and liquid limit of the amended bentonites were higher than those of the unamended bentonites.Permeation with acetic acid solutions with concentrations ranging from 40 mmol/L to 320 mmol/L conducted on the amended backfill only resulted in an increase in k of less than a factor of about 10 related to that based on permeation with tap water(4.41×10^(−11)-1.68×10^(−10) m/s to acetic acid solution versus 1.65×10^(−11) m/s to tap water).Mechanisms contributing to enhanced chemical compatibility of amended backfill were ascertained based on scanning electron microscopy,mercury intrusion porosimetry,and zeta potential analyses.展开更多
Super absorbent resin(SAR)is prepared by aqueous high temperature polymerization using hydroxypropyl methylcellulose(HPMC)as monomer backbone material,acrylic acid(AA)and acrylamide(AM)as the graft copolymer monomer,p...Super absorbent resin(SAR)is prepared by aqueous high temperature polymerization using hydroxypropyl methylcellulose(HPMC)as monomer backbone material,acrylic acid(AA)and acrylamide(AM)as the graft copolymer monomer,potassium persulfate(KPS)as the initiator to generate free radicals,and N,N`-methylenebisacrylamide(MBA)as cross-linking agent for cross-linking reaction.Simutaneously,the influence of individual factors on the water absorption is investigated,and these factors are mainly AA,AM,KPS,MBA,HPMC,and reaction temperature.The optimized conditions are obtained by the experiment repeating for several times.The water absorption multiplicity and salt absorption multiplicity under the conditions are 782.4 and 132.5 g/g,respectivity.Furthermore,the effects of different temperatures and salt concentrations on its water absorption,as well as the swelling kinetics of SAR are studied.It is indicated the water-absorbing swelling process is mainly caused by the difference in water osmotic pressure and Na+concentration inside and outside the cross-linked molecular structure of the resin,which is not only consistent with the quasi-secondary kinetic model,but also with the Fick diffusion model.展开更多
[Objectives]To enhance the skin permeability of hydroxypropyl tetrahydropyrantriol and provide a reference for the subsequent prevention or treatment of skin aging.[Methods]The lyophilization process of hydroxypropyl ...[Objectives]To enhance the skin permeability of hydroxypropyl tetrahydropyrantriol and provide a reference for the subsequent prevention or treatment of skin aging.[Methods]The lyophilization process of hydroxypropyl tetrahydropyrantriol liposomes was investigated using a single factor method,and a quality evaluation system was established based on the appearance,particle size,PDI,and re-dispersibility of the lyophilized samples.[Results]The lyophilization process of hydroxypropyl tetrahydropyrantriol liposomes was determined by single factor experiments.The pre-freezing period was 16 h at-80℃,the total drying time was 36 h,and the addition of 10%mannitol-sucrose was used as the lyoprotectant.[Conclusions]The product prepared by the lyophilization method exhibits a fluffy and full appearance,with minimal shrinkage and collapse.The volume remains consistent before and after lyophilization,and the re-dispersibility is satisfactory.The re-dissolution process is rapid,and the particle size and polydispersity index(PDI)remain largely unchanged before and after lyophilization.展开更多
Objective and Impact Statement:The microspheres were widely utilized in the field of life sciences,and we have developed an innovative microelectromechanical system(MEMS)-based bioprinting technology(MBT)system for th...Objective and Impact Statement:The microspheres were widely utilized in the field of life sciences,and we have developed an innovative microelectromechanical system(MEMS)-based bioprinting technology(MBT)system for the preparation of the microspheres.The microspheres can be automatically and high-throughput produced with this cutting-edge system.Introduction and Methods:This paper mainly introduced a novel,efficient,and cost-effective approach for the microsphere fabrication with the MBT system.In this work,the whole microsphere production equipment was built and the optimal conditions(like concentration,drying temperature,frequency,and voltage)for generating uniform hydroxypropyl cellulose-cyclosporine A(HPC-CsA)and poly-l-lactic acid(PLLA)microspheres were explored.Results:Results demonstrated that the optimal uniformity of HPC-CsA microspheres was achieved at 2%(w/v)HPC-CsA mixture,45°C(drying temperature),1,000 Hz(frequency),and 25 V(voltage amplitude).CsA microspheres[coefficient of variation(CV):~9%]are successfully synthesized,and the drug encapsulation rate was 84.8%.The methodology was further used to produce PLLA microspheres with a diameter of~2.55μm,and the best CV value achieved 6.84%.Conclusion:This investigation fully highlighted the integration of MEMS and bioprinting as a promising tool for the microsphere fabrication,and this MBT system had huge potential applications in pharmaceutical formulations and medical aesthetics.展开更多
A new solvent of cellulose (1.5 mol/L NaOH/0.5 mol/L urea aqueous solution) was used as one of the homogeneous reaction media of polysaccharides for methylation, hydroxyethylation and hydroxypropylation. A water insol...A new solvent of cellulose (1.5 mol/L NaOH/0.5 mol/L urea aqueous solution) was used as one of the homogeneous reaction media of polysaccharides for methylation, hydroxyethylation and hydroxypropylation. A water insoluble β -(1—>3)-D-glucan, sample PCS3- isolated from fresh sclerotium of Poria cocos was sulfated in dimethyl sulfoxide (Me 2 SO), carboxymethylated in NaOH, isopropanol solution, as well as methylated, hydroxyethylated and hydroxypropylated in the new solvent system, respectively, to obtain five water-soluble derivatives coded as S-PCS3- C- PCS3- M-PCS3- HE-PCS3- and HP-PCS3- Their chemical structure and distribution of substitution were characterized by infrared spectroscopy (IR), elementary analysis (EA), 1 H-NMR, 13 C-NMR, 2D-COSY, 2D-TOCSY and 2D- 1 H-detected 1H 13C HMQC spectra. The results reveal that the relative reactivity of hydroxyl groups of the β -(1-?3)-D-glucan is in the order C-6 > C-4 > C-2 on the whole. The substitution of the samples S-PCS3- C-PCS3- and M-PCS3- occurred mainly at C-6 position and secondly at C-4 and C-2 positions, and that of HE-PCS3- occurred at C-6 and C-4 positions and of HP-PCS3- almost completely occurred at C-6 position. The degrees of substitution (DS) obtained from 13 C-NMR range from 0.23 to 1.27. The water solubility of the derivatives is in the order S-PCS3- >C-PCS3- >M-PCS3- >HE-PCS3- >HP-PCS3- This work provides a novel and nonpolluting process for the methylation, hydroxyethylation and hydroxypropylation of β -(1—>3)-D-glucan.展开更多
Bacterial cellulose produced by Acetobacter xylinum has been reacted with propyleneoxide to synthesize hydroxypropyl cellulose （HPC） under different reaction conditions while diluted by toluene. The effects of mass ...Bacterial cellulose produced by Acetobacter xylinum has been reacted with propyleneoxide to synthesize hydroxypropyl cellulose （HPC） under different reaction conditions while diluted by toluene. The effects of mass ratio of bacterial cellulose to propyleneoxide, dilutability of toluene, reaction temperature （T） and time （t） were investigated by series of experiments. The degree of substitution （DS）, hydroxypropyl content （A） and yield （η） were compared. The optimized product exhibited cold-water solubility and hot-water gelatinization in aqueous medium. Further study was carried out with FTIR, TGA, XRD, SEM and 13C-NMR for characterization. The water/air contact angle measurement reveals that it is a good hydrophobic material with good mechanical properties.展开更多
Hydroxypropyl chitosan(HP-chitosan) has been shown to have promising applications in a wide range of areas due to its biocompatibility, biodegradability and various biological activities, especially in the biomedical ...Hydroxypropyl chitosan(HP-chitosan) has been shown to have promising applications in a wide range of areas due to its biocompatibility, biodegradability and various biological activities, especially in the biomedical and pharmaceutical fields. However, it is not yet known about its pharmacokinetics and biodegradation performance, which are crucial for its clinical applications. In order to lay a foundation for its further applications and exploitations, here we carried out fluorescence intensity and GPC analyses to determine the pharmacokinetics mode of fluorescein isothiocyanate-labeled HP-chitosan(FITC-HP-chitosan) and its biodegradability. The results showed that after intraperitoneal administration at a dose of 10 mg per rat, FITC-HP-chitosan could be absorbed rapidly and distributed to liver, kidney and spleen through blood. It was indicated that FITC-HP-chitosan could be utilized effectively, and 88.47% of the FITC-HP-chitosan could be excreted by urine within 11 days with a molecular weight less than 10 k Da. Moreover, our data indicated that there was an obvious degradation process occurred in liver(< 10 k Da at 24 h). In summary, HP-chitosan has excellent bioavailability and biodegradability, suggesting the potential applications of hydroxypropyl-modified chitosan as materials in drug delivery, tissue engineering and biomedical area.展开更多
The novel quaternized hydroxypropyl cellulose-g-poly(THF-co-epichlorohydrin)graft copolymers,HPC-g-QCP(THF-co-ECH),have been successfully synthesized to combine the properties from hydrophilic hard HPC biomacromolecul...The novel quaternized hydroxypropyl cellulose-g-poly(THF-co-epichlorohydrin)graft copolymers,HPC-g-QCP(THF-co-ECH),have been successfully synthesized to combine the properties from hydrophilic hard HPC biomacromolecular backbone and hydrophobic flexible polyether branches.Firstly,the P(THF-co-ECH)living chains were synthesized by cationic ring-opening copolymerization of THF with ECH.Secondly,P(THF-co-ECH)living chains were grafted onto HPC backbone by reaction with-OH groups along HPC to produce HPC-g-P(THF-co-ECH)graft copolymers.Thirdly,the mentioned graft copolymers were quaternized by reaction with ternanyamine to generate functionalized HPC-g-QCP(THF-co-ECH).The HPC-g-QCP(THF-co-ECH)graft copolymers exhibited good antibacterial ability against S.aureus or E.coli bacteria.The ibuprofen(IBU)-loaded microparticles of HPC-g-(QC)P(THF-co-ECH)graft copolymers were prepared by electrospraying.The in vitro pH-responsive drug-release behavior of IBU reached up to 75%of drug-loaded at pH=7A.This quaternized graft copolymer was beneficial to solving the problems of a burst effect and fast release of HPC as drug carriers.展开更多
With potassium persulfate (KPS) as initiator, graft copolymerization of ethyl acrylate (EA) onto water-soluble hydroxypropyl methylcellulose (HPMC) was investigated in aqueous medium. Effects of monomer concentration,...With potassium persulfate (KPS) as initiator, graft copolymerization of ethyl acrylate (EA) onto water-soluble hydroxypropyl methylcellulose (HPMC) was investigated in aqueous medium. Effects of monomer concentration, initiator concentration, matrix concentration, and reaction temperature on the percentage of grafting (G) and grafting efficiency (G_E) were studied. The results show that G and G_E values both increase with the the increase of EA concentration and KPS concentration; when raising HPMC concentration from 0.12 mmol/L to 0.47 mmol/L, G decreases, while G_E increases;and when raising reaction temperature from 50 ℃ to 65 ℃,G increases, but G_E decreases. In addition, the graft copolymers were characterized by Fourier transform infrared (FTIR) spectra and transmission electron microscopy (TEM) methods.展开更多
Hydration heat effect of cement pastes and mechanism of hydroxypropyl methyl cellulose ether （HPMC） and expanded perlite in cement pastes were studied by means of hydration exothermic rate, hydration heat amount, FT...Hydration heat effect of cement pastes and mechanism of hydroxypropyl methyl cellulose ether （HPMC） and expanded perlite in cement pastes were studied by means of hydration exothermic rate, hydration heat amount, FTIR and TG-DTG. The results show that HPMC can significantly delay the hydration induction period and acceleration period of cement pastes. As mixing amount increased, hydration induction period of cement pastes enlarged and accelerated period gradually went back. At the same time, the amount of hydration heat gradually decreased. Expanded perlite had worse delay effects and less change of hydration heat amount of cement pastes than HPMC. HPMC changed the structure of C-S-H during cement hydration. The more amount of HPMC, the more obvious effect. However, EXP had little influence on the structure of C-S-H. At the same age, the content of Ca （OH）2 in cement pastes gradually decreased as the mixing amount increase of HPMC and expanded perlite, and had better delay effect than that single-doped with HPMC or expanded perlite when HPMC and expanded nerlite were both dooed in cement pastes.展开更多
Hydroxypropyl xanthan gum(HXG) was prepared from xanthan gum(XG) and propylene oxide under alkaline condition. Rheological and drag reduction properties of different concentrations of aqueous HXG and XG solution were ...Hydroxypropyl xanthan gum(HXG) was prepared from xanthan gum(XG) and propylene oxide under alkaline condition. Rheological and drag reduction properties of different concentrations of aqueous HXG and XG solution were studied. The micro-structure network of HXG and XG solutions was investigated by Cryo-FESEM. The results showed that HXG and XG solutions could exhibit shear thinning property. The apparent viscosity of6 g·L-1HXG solution was 1.25 times more than that of 6 g·L-1XG solution. The storage modulus G′ and the loss modulus G″ of HXG solutions were greater than those of XG solutions, and thixotropic and viscoelastic properties were more significant in HXG solutions. The HXG and XG solutions reduced the pressure drop of straight pipe, and the maximum drag reduction of 1 g·L-1HXG and XG in smooth tube reached 72.8% and 68.1%, respectively. Drag reduction rate was increased as the concentration increased. The HXG solution may become a new polymeric drag reducer.展开更多
The novel reactive transfer printing of silk was carried out through a hot-press adhesion and steaming. The special transfer paper was prepared by coating the paste mainly containing hot-melt adhesive hlgh-substituted...The novel reactive transfer printing of silk was carried out through a hot-press adhesion and steaming. The special transfer paper was prepared by coating the paste mainly containing hot-melt adhesive hlgh-substituted hydroxypropyl cellulose （H-HPC） and printing thickener earboxymethyl cellulose （CMC）. The effects of each ingredient in the paste on color yield of the prints and dye penetration were investigated. The major results indicate that, color yield is chiefly governed by the adhesion extent imparted by H-HPC, the type of fixing alkaline agent, and the content of urea. Trichloroacetic acid （TCAA） as the fixing alkaline agent and adding 5% urea can enhance the color depth obviously. Dye penetration depends on the coating quantity on the transfer paper, the contents of urea and dicyandiamide. The printed silk possesses a higher color yield, color fastness of grade 3 or above, clear sharpness, and good handle when the paste contains 3 % H-HPC, 0. 7 % CMC, 3 % TCAA, 5 % urea, 3 % dicyandiamide, and 0. 5 % physical sorbent nano-silica.展开更多
[Objectives] To explore the optimal process for preparing hydroxypropyl tetrahydropyrantriol liposomes. [Methods] A refractive index method was used to determine the content of hydroxypropyl tetrahydropyrantriol. Usin...[Objectives] To explore the optimal process for preparing hydroxypropyl tetrahydropyrantriol liposomes. [Methods] A refractive index method was used to determine the content of hydroxypropyl tetrahydropyrantriol. Using particle size distribution and encapsulation rate as evaluation indicators, the effects of hydration time, ratio of organic phase to aqueous phase, granulation method, as well as thin film dispersion and reverse evaporation methods on liposomes preparation were investigated, and the optimal preparation method was selected. Single factor experiments were used to screen the drug phospholipid ratio, ultrasound time, and phospholipid cholesterol ratio, and the preparation process was optimized through orthogonal experiments. [Results] The optimal process of preparing hydroxypropyl tetrahydropyrantriol liposomes was as below: 1 : 10 of drug phospholipid ratio, 6 min of ultrasound time, 4 : 1 of phospholipid cholesterol ratio, (60.94%±7.24%) of entrapment efficiency, (86.44±6.08) nm of particle size, (0.195±0.077) of PDI. [Conclusions] The optimal preparation process of hydroxypropyl tetrahydropyrantriol liposomes selected by orthogonal experiment could effectively improve the encapsulation efficiency of hydroxypropyl tetrahydropyranotriol and reduce particle size. Moreover, the method was stable and reliable.展开更多
The aims of this study were to prepare and characterize hydroxypropyl methylcellulose(HPMC)/polycarbophil(PC) mucoadhesive blend films saturated with propranolol hydrochloride(PNL)-loaded nanoparticles to improve perm...The aims of this study were to prepare and characterize hydroxypropyl methylcellulose(HPMC)/polycarbophil(PC) mucoadhesive blend films saturated with propranolol hydrochloride(PNL)-loaded nanoparticles to improve permeability of drugs that undergo firstpass metabolism. An ionic cross-linking method and film casting technique was used to prepare nanoparticles and mucoadhesive blend films, respectively. Increasing concentrations of PNL(70, 80, 90 mg/film) in HPMC/PC blend films containing PNL-loaded nanoparticles(PN-films) and HPMC/PC blend films containing PNL(80 mg/film) without nanoparticles(PPfilms) were prepared to test swelling, mucoadhesiveness, release, permeation and physicochemical properties. Scanning electron microscope(SEM) images showed a partially smooth surface with a wrinkled occurrence and spherically shaped, well-dispersed nanoparticles on the surface of PN-films containing PNL 80 mg/film(PN-films-80). The size of the nanoparticles on the surface of PN-films-80 was around 100 nm, which was similar to the nanoparticle size observed using light scattering technique. The swelling index(SI)of all PN-films and PP-films increased greatly in the first period time(10–20 min) and reached swelling equilibrium at 20 min and 30 min, respectively. For the PN-films, the concentration of PNL influenced the mucoadhesive properties and tended to be higher when the amount of PNL increased. Immediate release of all blend film formulations was found in early time points(10–30 min). After 120 min, the release of PN-films-70 was lower than the other PNfilms. Permeation studies using porcine buccal mucosa showed that inclusion of nanoparticles in the films increased the permeability of PNL compared to PP-films. Therefore, buccal administration of mucoadhesive blend films containing PNL-loaded nanoparticles could be a promising approach for drugs that undergo first-pass metabolism.展开更多
The novel amphiphilic graft copolymers with hydrophilic hard polar hydroxypropyl cellulose(HPC)backbone and hydrophobic soft nonpolar polyisobutylene(PIB)branches have been successfully synthesized through nucleophili...The novel amphiphilic graft copolymers with hydrophilic hard polar hydroxypropyl cellulose(HPC)backbone and hydrophobic soft nonpolar polyisobutylene(PIB)branches have been successfully synthesized through nucleophilic substitution reaction of living PIB chains carrying oxonium ions with the-OH groups along HPC backbone.The PIB branch length in the graft copolymers could be designed by living cationic polymerization and the grafting density could be adjusted by PIB+/-OH molar ratio.The living PIB chains carrying oxonium ion were prepared by transformation of allyl bromide end groups in the presence of AgCI0_(4) and silver nanoparticles(3.2±0.3 nm,0.7 wt%-1.8 wt%)generated in situ from AgBr.The phase-separation morphology was formed in the graft copolymers due to their incompatibility between backbone and branches.The hydrophilicity on the surface of graft copolymer films could be turned to hydrophobicity by increasing grafting density or/and length of PIB branches.The soft PIB segments in graft copolymers provided an unique surface wa self-assembly for ant卜protein adsorption against bovine serum albumin.A small amount of Ag nanoparticles in the copolymers contributed to good antibacterial activities against Staphylococcus aureus or Escherichia coli.展开更多
Polymers and polymeric composites have steadily reflected their importance in our daily life. Blending poly(vinyl alcohol) (PVA) with a potentially useful natural biopolymers such as hydroxypropyl cellulose (HPC) seem...Polymers and polymeric composites have steadily reflected their importance in our daily life. Blending poly(vinyl alcohol) (PVA) with a potentially useful natural biopolymers such as hydroxypropyl cellulose (HPC) seems to be an interesting way of preparing a polymeric blends. In the present work, blends of PVA/HPC of compositions (100/0, 90/10, 75/25, 50/50, 25/75, and 0/100 wt/wt%) were prepared to be used as bioequivalent materials. Thermal analyses [differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)], and X-ray diffraction (XRD) were employed to characterize and reveal the miscibility map and the structural properties of such blend system. The obtained results of the thermal analyses showed variations in the glass transition temperature (Tg) indicating the miscibility of the blend systems. Moreover, the changes in the melting temperature (Tm), shape and area were attributed to the different degrees of crystallinity and the existence of polymer-polymer interactions between PVA and HPC molecules. The X-ray diffraction (XRD) analysis showed broadening and sharpening of peaks at different HPC concentrations with PVA. This indicated changes in the crystallinity/amorphosity ratio, and also suggested that the miscibility between the amorphous components of homo-polymers PVA and HPC is possible. The results showed that HPC doped in PVA film can improve the thermal stability of the film under investigation, leading to interesting technological applications.展开更多
The purposes of this study are to prepare the generic extended release tablet of potassiumchloride(PC) 600 mg and to compare the absorption of potassium ion from the experimen-tal tablets to that of Kaleorid? LP 600 m...The purposes of this study are to prepare the generic extended release tablet of potassiumchloride(PC) 600 mg and to compare the absorption of potassium ion from the experimen-tal tablets to that of Kaleorid? LP 600 mg(Leo Pharmaceutical Products, Denmark). Car-nauba wax was used as retardant in the matrix core tablets. The core tablets were coatedwith blends of ethyl cellulose(EC) and hydroxypropyl methyl cellulose(HPMC) to modulatethe drug release. Results of a selective two-level, three-factor experiment design revealedthat a blend of 41.75% of EC and 58.25% of HPMC at 4.5% weight gained could produce thecoated tablets having dissolution profiles similar to those of Kaleorid?. A two-treatment,two-period, two-sequence crossover bioequivalence study was carried out on 24 healthyvolunteers to compare the absorption of potassium ion from experimental tablets to thatfrom Kaleorid?. The potassium ion in the urine was measured by a selective electrode of theADVIA 1650 system(Bayer) and used to calculate cumulative urinary excretion and urinaryexcretion rate. Results of 90 percent confidence interval analysis showed that the limits fornatural log-transformed cumulative urinary potassium excretion(Ln Ae 0-24) of test productwere in the range of 3.73–3.79 mEq, corresponding to 99.08%–100.92% of Kaleorid ?, respec-tively, and the limits for natural log-transformed maximal potassium excretion rate( R max) oftest product were in the range of 1.72–1.82 mEq/h, corresponding to 97.34%–102.66% of refer-ence product, respectively. Both of them fell within the bioequivalence interval(80%–125%)of reference product, proving that experimental product is bioequivalent to Kaleorid ?.展开更多
Nimodipine(NMDP)sustained release formulations were designed with hydroxypropylmethylcellulose(HPMC)as swellable polymer and with solid dispersion of the drug in polyvinyl pyrrolidone(K30).a water-soluble system.and c...Nimodipine(NMDP)sustained release formulations were designed with hydroxypropylmethylcellulose(HPMC)as swellable polymer and with solid dispersion of the drug in polyvinyl pyrrolidone(K30).a water-soluble system.and compressed into tablets by direct compression.Drug release kinetics from tablets withdifferent compositions was investigated in vitro.Results showed that dissolution process of NMDP from poroushydrophilic matrix conformed to zero-order release kinetics.The addition of microcrystalline cellulose to the porousswellable release system increased the NMDP release rate constant.The presence of hydroxyethylcellulose(HEC)inthe system,which had a lower viscosity,increased the drug release rate constant.When tablets were prepared withHPMC 40 mesh granulation,the release rate of the drug was sustained.These show that the dosage form may beformulated as a drug-polymer system with constant release at a desired rate.The release properties of the sustainedrelease tablets made by pure drug instead of drug solid dispersion were also investigated.In the present study,theoptimal formulations that constantly released the drug during 12 h were selected for in vivo analysis.展开更多
基金National Key Research and Development Program of China(No.2022YFC2905004).
文摘The problems of tailings storage and high-stress conditions in deep mining have emerged as critical factors that limit the security,efficiency,and sustainability of such mines.This study explores the potential to utilize tungsten tailings to create cementitious backfill(CTB)materials and investigates the macroscopic strength features and microscopic damage evolution mechanisms of different-sized CTBs with varying dosages of hydroxypropyl methyl cellulose(HPMC).Specimens with bottom diameters of 50,75,and 100 mm are combined with HPMC dosages of 0,0.15wt%,0.25wt%,and 0.35wt%.A diameter/height ratio of 1:2 is maintained for all CTB specimens.The experimental results show that as the HPMC dosage is increased from 0 to 0.35wt%,the uniaxial compressive strength(UCS)of the CTBs decreases significantly in a linear manner.The 75 mm×150 mm CTB specimen exhibits relatively high plasticity and toughness,with good plastic deformation and energy absorption capabilities,indicating significant size effects.HPMC introduces connected bubbles during the CTB pouring process,but it exhibits anti-segregation and anti-bleeding characteristics,thus reducing tailing settling.The hydration reaction of the CTB doped with HPMC is more uniform,and the Ca/Si atomic ratio dispersion at different sites is smaller.The three CTB sizes all exhibit combined tensile and shear failure,with the 75 mm×150 mm specimen exhibiting macroscopic tensile cracks and relatively few shear cracks.At the micro-scale,excessive ettringite and hydrated calcium silicate are interwoven and fuse,and the tungsten tailings are tightly wrapped.These results provide valuable data and notional insights for optimizing the fluidity of the backfill,and elucidate the strength and damage evolution of solidified materials during filling and extraction.This study contributes to the advancement of green,economical,safe,and sustainable mining practices.
基金National Natural Science Foundation of China (Grant No.42177133)Primary R&D Plan of Jiangsu Province (Grant No.BE2022830)Primary R&D Plan of Anhui Province (Grant No.2023t07020018).
文摘Soil-bentonite(SB)backfills in vertical cutoff walls are used extensively to contain contaminated groundwater.Previous studies show that the hydraulic conductivity of backfill can exceed the typically recommended maximum value(k=1×10^(−9) m/s)if exposed to groundwater impacted by organic acids commonly released from uncontrolled landfills and municipal solid waste dumps.Polymer amended backfills exhibit excellent chemical compatibility to metal-laden groundwater.However,few studies to date have explored the effect of organic acid contaminated groundwater on hydraulic performance of polymer amended backfills.This study presents an experimental investigation on the hydraulic performance and microstructural properties of a composite polymer amended backfill used to contain flow of acetic acid-laden groundwater.A series of laboratory experiments were performed to evaluate free-swell indices of the composite polymer amended bentonites,liquid limits of the composite polymer amended and unamended bentonites,and slump heights and hydraulic conductivity(k)values of the amended backfills to acetic acid solutions with varying concentrations.The results were compared with those of the unamended bentonites and unamended backfills reported in a previous study.The results showed that the free-swell index and liquid limit of the amended bentonites were higher than those of the unamended bentonites.Permeation with acetic acid solutions with concentrations ranging from 40 mmol/L to 320 mmol/L conducted on the amended backfill only resulted in an increase in k of less than a factor of about 10 related to that based on permeation with tap water(4.41×10^(−11)-1.68×10^(−10) m/s to acetic acid solution versus 1.65×10^(−11) m/s to tap water).Mechanisms contributing to enhanced chemical compatibility of amended backfill were ascertained based on scanning electron microscopy,mercury intrusion porosimetry,and zeta potential analyses.
基金Funded by National Natural Science Foundation of China(No.52174206)Shaanxi Provincial Department of Education Youth Innovation Team Construction Scientific Research Plan Project(No.21JP074)Shaanxi Provincial Department of Education Youth Innovation Team Scientific Research Plan Project(No.22JP047)。
文摘Super absorbent resin(SAR)is prepared by aqueous high temperature polymerization using hydroxypropyl methylcellulose(HPMC)as monomer backbone material,acrylic acid(AA)and acrylamide(AM)as the graft copolymer monomer,potassium persulfate(KPS)as the initiator to generate free radicals,and N,N`-methylenebisacrylamide(MBA)as cross-linking agent for cross-linking reaction.Simutaneously,the influence of individual factors on the water absorption is investigated,and these factors are mainly AA,AM,KPS,MBA,HPMC,and reaction temperature.The optimized conditions are obtained by the experiment repeating for several times.The water absorption multiplicity and salt absorption multiplicity under the conditions are 782.4 and 132.5 g/g,respectivity.Furthermore,the effects of different temperatures and salt concentrations on its water absorption,as well as the swelling kinetics of SAR are studied.It is indicated the water-absorbing swelling process is mainly caused by the difference in water osmotic pressure and Na+concentration inside and outside the cross-linked molecular structure of the resin,which is not only consistent with the quasi-secondary kinetic model,but also with the Fick diffusion model.
基金Youth Science Foundation Project of Sichuan Provincial Department of Science and Technology(2022NSFSC1437)Special Project of Scientific and Technological Research of Sichuan Provincial Administration of Traditional Chinese Medicine(2021MS121)Fundamental Research Funds for the Central Universities of Southwest Minzu University(ZYN2022040).
文摘[Objectives]To enhance the skin permeability of hydroxypropyl tetrahydropyrantriol and provide a reference for the subsequent prevention or treatment of skin aging.[Methods]The lyophilization process of hydroxypropyl tetrahydropyrantriol liposomes was investigated using a single factor method,and a quality evaluation system was established based on the appearance,particle size,PDI,and re-dispersibility of the lyophilized samples.[Results]The lyophilization process of hydroxypropyl tetrahydropyrantriol liposomes was determined by single factor experiments.The pre-freezing period was 16 h at-80℃,the total drying time was 36 h,and the addition of 10%mannitol-sucrose was used as the lyoprotectant.[Conclusions]The product prepared by the lyophilization method exhibits a fluffy and full appearance,with minimal shrinkage and collapse.The volume remains consistent before and after lyophilization,and the re-dispersibility is satisfactory.The re-dissolution process is rapid,and the particle size and polydispersity index(PDI)remain largely unchanged before and after lyophilization.
基金sponsored by Shanghai Pujiang Program(23PJ1423400)Shanghai Rising-Star Program(23QB1405100)National Key Research and Development Program of China(2019YFA0707004 and SQ2021YFF0700202).
文摘Objective and Impact Statement:The microspheres were widely utilized in the field of life sciences,and we have developed an innovative microelectromechanical system(MEMS)-based bioprinting technology(MBT)system for the preparation of the microspheres.The microspheres can be automatically and high-throughput produced with this cutting-edge system.Introduction and Methods:This paper mainly introduced a novel,efficient,and cost-effective approach for the microsphere fabrication with the MBT system.In this work,the whole microsphere production equipment was built and the optimal conditions(like concentration,drying temperature,frequency,and voltage)for generating uniform hydroxypropyl cellulose-cyclosporine A(HPC-CsA)and poly-l-lactic acid(PLLA)microspheres were explored.Results:Results demonstrated that the optimal uniformity of HPC-CsA microspheres was achieved at 2%(w/v)HPC-CsA mixture,45°C(drying temperature),1,000 Hz(frequency),and 25 V(voltage amplitude).CsA microspheres[coefficient of variation(CV):~9%]are successfully synthesized,and the drug encapsulation rate was 84.8%.The methodology was further used to produce PLLA microspheres with a diameter of~2.55μm,and the best CV value achieved 6.84%.Conclusion:This investigation fully highlighted the integration of MEMS and bioprinting as a promising tool for the microsphere fabrication,and this MBT system had huge potential applications in pharmaceutical formulations and medical aesthetics.
基金This work was supported by the National Natural Science Foundation of China (No. 20074025), the Area of Excellence(AoE) on Plant and Fungal Biotechnology Project of the Hong Kong SAR Government and Key Laboratory of Cellulose andLignocellulosic Chemistry of Chinese Academy of Sciences.
文摘A new solvent of cellulose (1.5 mol/L NaOH/0.5 mol/L urea aqueous solution) was used as one of the homogeneous reaction media of polysaccharides for methylation, hydroxyethylation and hydroxypropylation. A water insoluble β -(1—>3)-D-glucan, sample PCS3- isolated from fresh sclerotium of Poria cocos was sulfated in dimethyl sulfoxide (Me 2 SO), carboxymethylated in NaOH, isopropanol solution, as well as methylated, hydroxyethylated and hydroxypropylated in the new solvent system, respectively, to obtain five water-soluble derivatives coded as S-PCS3- C- PCS3- M-PCS3- HE-PCS3- and HP-PCS3- Their chemical structure and distribution of substitution were characterized by infrared spectroscopy (IR), elementary analysis (EA), 1 H-NMR, 13 C-NMR, 2D-COSY, 2D-TOCSY and 2D- 1 H-detected 1H 13C HMQC spectra. The results reveal that the relative reactivity of hydroxyl groups of the β -(1-?3)-D-glucan is in the order C-6 > C-4 > C-2 on the whole. The substitution of the samples S-PCS3- C-PCS3- and M-PCS3- occurred mainly at C-6 position and secondly at C-4 and C-2 positions, and that of HE-PCS3- occurred at C-6 and C-4 positions and of HP-PCS3- almost completely occurred at C-6 position. The degrees of substitution (DS) obtained from 13 C-NMR range from 0.23 to 1.27. The water solubility of the derivatives is in the order S-PCS3- >C-PCS3- >M-PCS3- >HE-PCS3- >HP-PCS3- This work provides a novel and nonpolluting process for the methylation, hydroxyethylation and hydroxypropylation of β -(1—>3)-D-glucan.
基金financially supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD) and the Jiangsu Provincial Department of Personnel,the National High Technology Research and Development Program of China(863 Program2010AA0500293002)
文摘Bacterial cellulose produced by Acetobacter xylinum has been reacted with propyleneoxide to synthesize hydroxypropyl cellulose （HPC） under different reaction conditions while diluted by toluene. The effects of mass ratio of bacterial cellulose to propyleneoxide, dilutability of toluene, reaction temperature （T） and time （t） were investigated by series of experiments. The degree of substitution （DS）, hydroxypropyl content （A） and yield （η） were compared. The optimized product exhibited cold-water solubility and hot-water gelatinization in aqueous medium. Further study was carried out with FTIR, TGA, XRD, SEM and 13C-NMR for characterization. The water/air contact angle measurement reveals that it is a good hydrophobic material with good mechanical properties.
基金financially supported by National High Technology Research and Development Program of China(863 Program,Grant No.2007AA091603)
文摘Hydroxypropyl chitosan(HP-chitosan) has been shown to have promising applications in a wide range of areas due to its biocompatibility, biodegradability and various biological activities, especially in the biomedical and pharmaceutical fields. However, it is not yet known about its pharmacokinetics and biodegradation performance, which are crucial for its clinical applications. In order to lay a foundation for its further applications and exploitations, here we carried out fluorescence intensity and GPC analyses to determine the pharmacokinetics mode of fluorescein isothiocyanate-labeled HP-chitosan(FITC-HP-chitosan) and its biodegradability. The results showed that after intraperitoneal administration at a dose of 10 mg per rat, FITC-HP-chitosan could be absorbed rapidly and distributed to liver, kidney and spleen through blood. It was indicated that FITC-HP-chitosan could be utilized effectively, and 88.47% of the FITC-HP-chitosan could be excreted by urine within 11 days with a molecular weight less than 10 k Da. Moreover, our data indicated that there was an obvious degradation process occurred in liver(< 10 k Da at 24 h). In summary, HP-chitosan has excellent bioavailability and biodegradability, suggesting the potential applications of hydroxypropyl-modified chitosan as materials in drug delivery, tissue engineering and biomedical area.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21574007 and 51521062).
文摘The novel quaternized hydroxypropyl cellulose-g-poly(THF-co-epichlorohydrin)graft copolymers,HPC-g-QCP(THF-co-ECH),have been successfully synthesized to combine the properties from hydrophilic hard HPC biomacromolecular backbone and hydrophobic flexible polyether branches.Firstly,the P(THF-co-ECH)living chains were synthesized by cationic ring-opening copolymerization of THF with ECH.Secondly,P(THF-co-ECH)living chains were grafted onto HPC backbone by reaction with-OH groups along HPC to produce HPC-g-P(THF-co-ECH)graft copolymers.Thirdly,the mentioned graft copolymers were quaternized by reaction with ternanyamine to generate functionalized HPC-g-QCP(THF-co-ECH).The HPC-g-QCP(THF-co-ECH)graft copolymers exhibited good antibacterial ability against S.aureus or E.coli bacteria.The ibuprofen(IBU)-loaded microparticles of HPC-g-(QC)P(THF-co-ECH)graft copolymers were prepared by electrospraying.The in vitro pH-responsive drug-release behavior of IBU reached up to 75%of drug-loaded at pH=7A.This quaternized graft copolymer was beneficial to solving the problems of a burst effect and fast release of HPC as drug carriers.
文摘With potassium persulfate (KPS) as initiator, graft copolymerization of ethyl acrylate (EA) onto water-soluble hydroxypropyl methylcellulose (HPMC) was investigated in aqueous medium. Effects of monomer concentration, initiator concentration, matrix concentration, and reaction temperature on the percentage of grafting (G) and grafting efficiency (G_E) were studied. The results show that G and G_E values both increase with the the increase of EA concentration and KPS concentration; when raising HPMC concentration from 0.12 mmol/L to 0.47 mmol/L, G decreases, while G_E increases;and when raising reaction temperature from 50 ℃ to 65 ℃,G increases, but G_E decreases. In addition, the graft copolymers were characterized by Fourier transform infrared (FTIR) spectra and transmission electron microscopy (TEM) methods.
基金Funded by the National Natural Science Foundation of China(No.50902107)National Science and Technology Supporting Program (No.2011BAJ04B02)the Fundamental Research Funds for the Central Universities (No.2011-YB-03)
文摘Hydration heat effect of cement pastes and mechanism of hydroxypropyl methyl cellulose ether （HPMC） and expanded perlite in cement pastes were studied by means of hydration exothermic rate, hydration heat amount, FTIR and TG-DTG. The results show that HPMC can significantly delay the hydration induction period and acceleration period of cement pastes. As mixing amount increased, hydration induction period of cement pastes enlarged and accelerated period gradually went back. At the same time, the amount of hydration heat gradually decreased. Expanded perlite had worse delay effects and less change of hydration heat amount of cement pastes than HPMC. HPMC changed the structure of C-S-H during cement hydration. The more amount of HPMC, the more obvious effect. However, EXP had little influence on the structure of C-S-H. At the same age, the content of Ca （OH）2 in cement pastes gradually decreased as the mixing amount increase of HPMC and expanded perlite, and had better delay effect than that single-doped with HPMC or expanded perlite when HPMC and expanded nerlite were both dooed in cement pastes.
基金Supported by the National High Technology Research and Development Program of China(2013AA064801)
文摘Hydroxypropyl xanthan gum(HXG) was prepared from xanthan gum(XG) and propylene oxide under alkaline condition. Rheological and drag reduction properties of different concentrations of aqueous HXG and XG solution were studied. The micro-structure network of HXG and XG solutions was investigated by Cryo-FESEM. The results showed that HXG and XG solutions could exhibit shear thinning property. The apparent viscosity of6 g·L-1HXG solution was 1.25 times more than that of 6 g·L-1XG solution. The storage modulus G′ and the loss modulus G″ of HXG solutions were greater than those of XG solutions, and thixotropic and viscoelastic properties were more significant in HXG solutions. The HXG and XG solutions reduced the pressure drop of straight pipe, and the maximum drag reduction of 1 g·L-1HXG and XG in smooth tube reached 72.8% and 68.1%, respectively. Drag reduction rate was increased as the concentration increased. The HXG solution may become a new polymeric drag reducer.
基金Jiangsu Province Project of Postgraduate Innovation Engineering,China(No.CXZZ12_0821)Industry-academic Joint Technological Innovations Fund Project of Jiangsu Province,China(No.BY2012120)Suzhou Project of Scientific and Technical Supporting,China(No.ZXS2012001)
文摘The novel reactive transfer printing of silk was carried out through a hot-press adhesion and steaming. The special transfer paper was prepared by coating the paste mainly containing hot-melt adhesive hlgh-substituted hydroxypropyl cellulose （H-HPC） and printing thickener earboxymethyl cellulose （CMC）. The effects of each ingredient in the paste on color yield of the prints and dye penetration were investigated. The major results indicate that, color yield is chiefly governed by the adhesion extent imparted by H-HPC, the type of fixing alkaline agent, and the content of urea. Trichloroacetic acid （TCAA） as the fixing alkaline agent and adding 5% urea can enhance the color depth obviously. Dye penetration depends on the coating quantity on the transfer paper, the contents of urea and dicyandiamide. The printed silk possesses a higher color yield, color fastness of grade 3 or above, clear sharpness, and good handle when the paste contains 3 % H-HPC, 0. 7 % CMC, 3 % TCAA, 5 % urea, 3 % dicyandiamide, and 0. 5 % physical sorbent nano-silica.
基金Supported by Innovation and Entrepreneurship Training Program Project of Southwest Minzu University(S202210656134)Project of Sichuan Department of Science and Technology(2022NSFSC1437)Project of Sichuan Administration of Traditional Chinese Medicine(2021MS121).
文摘[Objectives] To explore the optimal process for preparing hydroxypropyl tetrahydropyrantriol liposomes. [Methods] A refractive index method was used to determine the content of hydroxypropyl tetrahydropyrantriol. Using particle size distribution and encapsulation rate as evaluation indicators, the effects of hydration time, ratio of organic phase to aqueous phase, granulation method, as well as thin film dispersion and reverse evaporation methods on liposomes preparation were investigated, and the optimal preparation method was selected. Single factor experiments were used to screen the drug phospholipid ratio, ultrasound time, and phospholipid cholesterol ratio, and the preparation process was optimized through orthogonal experiments. [Results] The optimal process of preparing hydroxypropyl tetrahydropyrantriol liposomes was as below: 1 : 10 of drug phospholipid ratio, 6 min of ultrasound time, 4 : 1 of phospholipid cholesterol ratio, (60.94%±7.24%) of entrapment efficiency, (86.44±6.08) nm of particle size, (0.195±0.077) of PDI. [Conclusions] The optimal preparation process of hydroxypropyl tetrahydropyrantriol liposomes selected by orthogonal experiment could effectively improve the encapsulation efficiency of hydroxypropyl tetrahydropyranotriol and reduce particle size. Moreover, the method was stable and reliable.
基金the financial support provided by Thammasat University under the TU Research Scholar,Contract No.TP 2/68/2556
文摘The aims of this study were to prepare and characterize hydroxypropyl methylcellulose(HPMC)/polycarbophil(PC) mucoadhesive blend films saturated with propranolol hydrochloride(PNL)-loaded nanoparticles to improve permeability of drugs that undergo firstpass metabolism. An ionic cross-linking method and film casting technique was used to prepare nanoparticles and mucoadhesive blend films, respectively. Increasing concentrations of PNL(70, 80, 90 mg/film) in HPMC/PC blend films containing PNL-loaded nanoparticles(PN-films) and HPMC/PC blend films containing PNL(80 mg/film) without nanoparticles(PPfilms) were prepared to test swelling, mucoadhesiveness, release, permeation and physicochemical properties. Scanning electron microscope(SEM) images showed a partially smooth surface with a wrinkled occurrence and spherically shaped, well-dispersed nanoparticles on the surface of PN-films containing PNL 80 mg/film(PN-films-80). The size of the nanoparticles on the surface of PN-films-80 was around 100 nm, which was similar to the nanoparticle size observed using light scattering technique. The swelling index(SI)of all PN-films and PP-films increased greatly in the first period time(10–20 min) and reached swelling equilibrium at 20 min and 30 min, respectively. For the PN-films, the concentration of PNL influenced the mucoadhesive properties and tended to be higher when the amount of PNL increased. Immediate release of all blend film formulations was found in early time points(10–30 min). After 120 min, the release of PN-films-70 was lower than the other PNfilms. Permeation studies using porcine buccal mucosa showed that inclusion of nanoparticles in the films increased the permeability of PNL compared to PP-films. Therefore, buccal administration of mucoadhesive blend films containing PNL-loaded nanoparticles could be a promising approach for drugs that undergo first-pass metabolism.
基金the National Natural Science Foundation of China(Nos.21574007 and 51521062)the Fundamental Research Funds for the Central Universities(Nos.XK1802-2 and XK1802-1).
文摘The novel amphiphilic graft copolymers with hydrophilic hard polar hydroxypropyl cellulose(HPC)backbone and hydrophobic soft nonpolar polyisobutylene(PIB)branches have been successfully synthesized through nucleophilic substitution reaction of living PIB chains carrying oxonium ions with the-OH groups along HPC backbone.The PIB branch length in the graft copolymers could be designed by living cationic polymerization and the grafting density could be adjusted by PIB+/-OH molar ratio.The living PIB chains carrying oxonium ion were prepared by transformation of allyl bromide end groups in the presence of AgCI0_(4) and silver nanoparticles(3.2±0.3 nm,0.7 wt%-1.8 wt%)generated in situ from AgBr.The phase-separation morphology was formed in the graft copolymers due to their incompatibility between backbone and branches.The hydrophilicity on the surface of graft copolymer films could be turned to hydrophobicity by increasing grafting density or/and length of PIB branches.The soft PIB segments in graft copolymers provided an unique surface wa self-assembly for ant卜protein adsorption against bovine serum albumin.A small amount of Ag nanoparticles in the copolymers contributed to good antibacterial activities against Staphylococcus aureus or Escherichia coli.
文摘Polymers and polymeric composites have steadily reflected their importance in our daily life. Blending poly(vinyl alcohol) (PVA) with a potentially useful natural biopolymers such as hydroxypropyl cellulose (HPC) seems to be an interesting way of preparing a polymeric blends. In the present work, blends of PVA/HPC of compositions (100/0, 90/10, 75/25, 50/50, 25/75, and 0/100 wt/wt%) were prepared to be used as bioequivalent materials. Thermal analyses [differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)], and X-ray diffraction (XRD) were employed to characterize and reveal the miscibility map and the structural properties of such blend system. The obtained results of the thermal analyses showed variations in the glass transition temperature (Tg) indicating the miscibility of the blend systems. Moreover, the changes in the melting temperature (Tm), shape and area were attributed to the different degrees of crystallinity and the existence of polymer-polymer interactions between PVA and HPC molecules. The X-ray diffraction (XRD) analysis showed broadening and sharpening of peaks at different HPC concentrations with PVA. This indicated changes in the crystallinity/amorphosity ratio, and also suggested that the miscibility between the amorphous components of homo-polymers PVA and HPC is possible. The results showed that HPC doped in PVA film can improve the thermal stability of the film under investigation, leading to interesting technological applications.
基金Financial support for bioequivalence study from The Department of Science and Technology (grant number 209/HDSKHCN) of Ho chi Minh city (DOST)
文摘The purposes of this study are to prepare the generic extended release tablet of potassiumchloride(PC) 600 mg and to compare the absorption of potassium ion from the experimen-tal tablets to that of Kaleorid? LP 600 mg(Leo Pharmaceutical Products, Denmark). Car-nauba wax was used as retardant in the matrix core tablets. The core tablets were coatedwith blends of ethyl cellulose(EC) and hydroxypropyl methyl cellulose(HPMC) to modulatethe drug release. Results of a selective two-level, three-factor experiment design revealedthat a blend of 41.75% of EC and 58.25% of HPMC at 4.5% weight gained could produce thecoated tablets having dissolution profiles similar to those of Kaleorid?. A two-treatment,two-period, two-sequence crossover bioequivalence study was carried out on 24 healthyvolunteers to compare the absorption of potassium ion from experimental tablets to thatfrom Kaleorid?. The potassium ion in the urine was measured by a selective electrode of theADVIA 1650 system(Bayer) and used to calculate cumulative urinary excretion and urinaryexcretion rate. Results of 90 percent confidence interval analysis showed that the limits fornatural log-transformed cumulative urinary potassium excretion(Ln Ae 0-24) of test productwere in the range of 3.73–3.79 mEq, corresponding to 99.08%–100.92% of Kaleorid ?, respec-tively, and the limits for natural log-transformed maximal potassium excretion rate( R max) oftest product were in the range of 1.72–1.82 mEq/h, corresponding to 97.34%–102.66% of refer-ence product, respectively. Both of them fell within the bioequivalence interval(80%–125%)of reference product, proving that experimental product is bioequivalent to Kaleorid ?.
文摘Nimodipine(NMDP)sustained release formulations were designed with hydroxypropylmethylcellulose(HPMC)as swellable polymer and with solid dispersion of the drug in polyvinyl pyrrolidone(K30).a water-soluble system.and compressed into tablets by direct compression.Drug release kinetics from tablets withdifferent compositions was investigated in vitro.Results showed that dissolution process of NMDP from poroushydrophilic matrix conformed to zero-order release kinetics.The addition of microcrystalline cellulose to the porousswellable release system increased the NMDP release rate constant.The presence of hydroxyethylcellulose(HEC)inthe system,which had a lower viscosity,increased the drug release rate constant.When tablets were prepared withHPMC 40 mesh granulation,the release rate of the drug was sustained.These show that the dosage form may beformulated as a drug-polymer system with constant release at a desired rate.The release properties of the sustainedrelease tablets made by pure drug instead of drug solid dispersion were also investigated.In the present study,theoptimal formulations that constantly released the drug during 12 h were selected for in vivo analysis.
