Most of the newly developed drug candidates are lipophilic and poorly water-soluble. Enhancing the dissolution and bioavailability of these drugs is a major challenge for the pharmaceutical industry. Liquisolid techni...Most of the newly developed drug candidates are lipophilic and poorly water-soluble. Enhancing the dissolution and bioavailability of these drugs is a major challenge for the pharmaceutical industry. Liquisolid technique, which is based on the conversion of the drug in liquid state into an apparently dry, non-adherent, free flowing and compressible powder,is a novel and advanced approach to tackle the issue. The objective of this article is to present an overview of liquisolid technique and summarize the progress of its applications in pharmaceutics. Low cost, simple processing and great potentials in industrial production are main advantages of this approach. In addition to the enhancement of dissolution rate of poorly water-soluble drugs, this technique is also a fairly new technique to effectively retard drug release. Furthermore, liquisolid technique has been investigated as a tool to minimize the effect of pH variation on drug release and as a promising alternative to conventional coating for the improvement of drug photostability in solid dosage forms. Overall, liquisolid technique is a newly developed and promising tool for enhancing drug dissolution and sustaining drug release, and its potential applications in pharmaceutics are still being broadened.展开更多
The aim of this study was to improve the dissolution rate of the poorly soluble drug valsartan by delivering the drug as a liquisolid compact.Liquisolid compacts were prepared using propylene glycol as solvent,Avicel ...The aim of this study was to improve the dissolution rate of the poorly soluble drug valsartan by delivering the drug as a liquisolid compact.Liquisolid compacts were prepared using propylene glycol as solvent,Avicel PH102 as carrier,and Aerosil 200 as the coating material.The crystallinity of the newly formulated drug and the interaction between excipients was examined by X-ray powder diffraction and Fourier-transform infrared spectroscopy,respectively.The dissolution studies for the liquisolid formula-tion and the marketed product were carried out at different pH values.The results showed no change in the crystallinity of the drug and no interaction between excipients.The dissolution efficiency of valsartan at 15 min was increased from 4.02% for plain drug and 13.58% for marketed product to 29.47% for the liquisolid formulation.The increase in the dissolution rate was also found to be significant compared to the marketed product at lower pH values,simulating the gastric environment where valsartan is largely absorbed.The liquisolid technique appears to be a promising approach for improving the dissolution of poorly soluble drugs like valsartan.展开更多
Elasto-plastic consolidation is one of the classic coupling questions in geomechanics. To solve this problem, an elasto-plastic constitutive model is derived based on the numerical modeling method. The model is applie...Elasto-plastic consolidation is one of the classic coupling questions in geomechanics. To solve this problem, an elasto-plastic constitutive model is derived based on the numerical modeling method. The model is applied to Blot＇s consolidation theory. Incremental governing partial differential equations are established using this method. According to the stress path, the decoupling condition of these equations is discussed. Based on these conditions, an incremental diffusion equation and uncoupling governing equations are presented. The method is then applied to numerical analyses of three examples. The results show that （1） the effect of the stress path should be taken into account in the simulation of the soil consolidation question; （2） this decoupling method can predict the evolvement of pore water pressure; （3） the settlement using cam-clay model is less than that using numerical model because of dilatancy.展开更多
The present research aimed to improve the dissolution rate and bioavailability of curcumin using the potential of liquisolid technology. Twelve drug-loaded liquisolid systems(LS-1 to LS-12) were prepared using differe...The present research aimed to improve the dissolution rate and bioavailability of curcumin using the potential of liquisolid technology. Twelve drug-loaded liquisolid systems(LS-1 to LS-12) were prepared using different vehicles(PEG 200, PEG 400 and Tween 80) and curcumin concentrations in vehicle(40%, 50%, 60% and 70%, w/w). The carrier [microcrystalline cellulose(MCC) PH102] to coat(Aerosils) ratio was 20 in all formulations. The systems were screened for pre-compression properties before being compressed to liquisolid tablets(LT-1 to LT-12). Post compression tests and in vitro dissolution of LTs were conducted and the results compared with those obtained for a directly compressed tablet(DCT) made of curcumin, MCC PH102 and Aerosils. LTs exhibited higher cumulative drug release(CDR) than the DCT and the optimum formulation, LT-9(made using Tween 80), was studied by powder XRD, DSC, SEM and FTIR. Ex-vivo permeation of curcumin from LT-9 through goat gastrointestinal mucosa was significantly(Po0.05) enhanced and its oral bioavailability was increased18.6-fold in New Zealand rabbits. In vitro cytotoxicity(IC50) of LT-9 towards NCL 87 cancer cells was40.2 mmol/L substantiating its anticancer efficacy. Accelerated stability studies revealed insignificant effects of temperature and humidity on LT-9. In summary, solubility enhancement of curcumin in LTs produced significant improvements in its permeation and bioavailability.展开更多
文摘Most of the newly developed drug candidates are lipophilic and poorly water-soluble. Enhancing the dissolution and bioavailability of these drugs is a major challenge for the pharmaceutical industry. Liquisolid technique, which is based on the conversion of the drug in liquid state into an apparently dry, non-adherent, free flowing and compressible powder,is a novel and advanced approach to tackle the issue. The objective of this article is to present an overview of liquisolid technique and summarize the progress of its applications in pharmaceutics. Low cost, simple processing and great potentials in industrial production are main advantages of this approach. In addition to the enhancement of dissolution rate of poorly water-soluble drugs, this technique is also a fairly new technique to effectively retard drug release. Furthermore, liquisolid technique has been investigated as a tool to minimize the effect of pH variation on drug release and as a promising alternative to conventional coating for the improvement of drug photostability in solid dosage forms. Overall, liquisolid technique is a newly developed and promising tool for enhancing drug dissolution and sustaining drug release, and its potential applications in pharmaceutics are still being broadened.
文摘The aim of this study was to improve the dissolution rate of the poorly soluble drug valsartan by delivering the drug as a liquisolid compact.Liquisolid compacts were prepared using propylene glycol as solvent,Avicel PH102 as carrier,and Aerosil 200 as the coating material.The crystallinity of the newly formulated drug and the interaction between excipients was examined by X-ray powder diffraction and Fourier-transform infrared spectroscopy,respectively.The dissolution studies for the liquisolid formula-tion and the marketed product were carried out at different pH values.The results showed no change in the crystallinity of the drug and no interaction between excipients.The dissolution efficiency of valsartan at 15 min was increased from 4.02% for plain drug and 13.58% for marketed product to 29.47% for the liquisolid formulation.The increase in the dissolution rate was also found to be significant compared to the marketed product at lower pH values,simulating the gastric environment where valsartan is largely absorbed.The liquisolid technique appears to be a promising approach for improving the dissolution of poorly soluble drugs like valsartan.
文摘Elasto-plastic consolidation is one of the classic coupling questions in geomechanics. To solve this problem, an elasto-plastic constitutive model is derived based on the numerical modeling method. The model is applied to Blot＇s consolidation theory. Incremental governing partial differential equations are established using this method. According to the stress path, the decoupling condition of these equations is discussed. Based on these conditions, an incremental diffusion equation and uncoupling governing equations are presented. The method is then applied to numerical analyses of three examples. The results show that （1） the effect of the stress path should be taken into account in the simulation of the soil consolidation question; （2） this decoupling method can predict the evolvement of pore water pressure; （3） the settlement using cam-clay model is less than that using numerical model because of dilatancy.
文摘The present research aimed to improve the dissolution rate and bioavailability of curcumin using the potential of liquisolid technology. Twelve drug-loaded liquisolid systems(LS-1 to LS-12) were prepared using different vehicles(PEG 200, PEG 400 and Tween 80) and curcumin concentrations in vehicle(40%, 50%, 60% and 70%, w/w). The carrier [microcrystalline cellulose(MCC) PH102] to coat(Aerosils) ratio was 20 in all formulations. The systems were screened for pre-compression properties before being compressed to liquisolid tablets(LT-1 to LT-12). Post compression tests and in vitro dissolution of LTs were conducted and the results compared with those obtained for a directly compressed tablet(DCT) made of curcumin, MCC PH102 and Aerosils. LTs exhibited higher cumulative drug release(CDR) than the DCT and the optimum formulation, LT-9(made using Tween 80), was studied by powder XRD, DSC, SEM and FTIR. Ex-vivo permeation of curcumin from LT-9 through goat gastrointestinal mucosa was significantly(Po0.05) enhanced and its oral bioavailability was increased18.6-fold in New Zealand rabbits. In vitro cytotoxicity(IC50) of LT-9 towards NCL 87 cancer cells was40.2 mmol/L substantiating its anticancer efficacy. Accelerated stability studies revealed insignificant effects of temperature and humidity on LT-9. In summary, solubility enhancement of curcumin in LTs produced significant improvements in its permeation and bioavailability.
