A novel three-dimensional large-pore mesoporous carbon matrix as a potential nanovehicle for the fast release of the poorly water-soluble drug, celecoxib.

PURPOSE: A novel mesocellular carbon foam (MSU-FC) with a large pore size and a three-dimensional porous structure for the oral delivery of poorly water-soluble drugs was prepared. The goal of this study was to improve in vitro dissolution and in vivo absorption of celecoxib (CEB), a model drug, by means of novel carbon-based nanoparticles prepared from the MSU-FC matrix. METHODS: The MSU-FC matrix was synthesized by an inverse replica templating method using mesocellular silica template. A solvent immersion/evaporation method was used to load the drug molecules. The drug-loaded nanoparticles were characterized for morphology, surface area, particle size, mesoporous structure, crystallinity, solubility and dissolution. The effect of MSU-FC on cell viability was measured using the MTT conversion assay. Furthermore, the oral bioavailability of CEB-loaded MSU-FC in fasted rats was compared with that of the marketed product. RESULTS: Our results demonstrate that CEB incorporation into the prepared MSU-FC resulted in an approximately 9-fold increase in aqueous solubility in comparison with crystalline CEB. MSU-FC produced accelerated immediate release of CEB in comparison with crystalline CEB (pure CEB powder or marketed formulation) and the drug-loaded conventional mesoporous carbon particles. The relative bioavailability of CEB for CEB-loaded MSU-FC was 172%. In addition, MSU-FC nanoparticles exhibited very low toxicity. CONCLUSIONS: The MSU-FC nanomatrix has been shown to be a promising drug delivery vehicle for improving the dissolution and biopharmaceutical characteristics of poorly water-soluble drugs.

[Study on the stability of resveratrol in rhizoma polygoni cuspidati].

OBJECTIVE: The stability of resveratrol in Rhizoma Polygoni Cuspidati is evaluated all-roundly. METHODS: We not only increase influence intensity by physical, chemical and biological methods but also parallel analyzing the influence results to elicit the opinions. RESULTS: The content of resveratrol is declied greatly by lighting, heating, wet-heating or oxidizing. The content is increased in Rhizoma Polygoni Cuspidati treated with acid or alkali only using sodium hydroxide until pH=11. The content is not increased when its own activated microbe is destroyed. CONCLUSION: Resveratrol is unstable against light, heat, wet-heating and oxidizer. Its own activated microbe has not influenced to it. It has not benefit with acidification. Its solubility and stability increase formed sodium salt with basification.

Increasing the dissolution rate and oral bioavailability of the poorly water-soluble drug valsartan using novel hierarchical porous carbon monoliths.

In the present study, a novel hierarchical porous carbon monolith (HPCM) with three-dimensionally (3D) ordered macropores (∼ 400 nm) and uniform accessible mesopores (∼ 5.2 nm) was synthesized via a facile dual-templating technique using colloidal silica nanospheres and Poloxamer 407 as templates. The feasibility of the prepared HPCM for oral drug delivery was studied. Valsartan (VAL) was chosen as a poorly water-soluble model drug and loaded into the HPCM matrix using the solvent evaporation method. Scanning electron microscopy (SEM) and specific surface area analysis were employed to characterize the drug-loaded HPCM-based formulation, confirming the successful inclusion of VAL into the nanopores of HPCM. Powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) demonstrated that the incorporated drug in the HPCM matrix was in an amorphous state and the VAL formulation exhibited good physical stability for up to 6 months. In vitro tests showed that the dissolution rate of HPCM-based formulation was increased significantly compared with that of crystalline VAL or VAL-loaded 3D ordered macroporous carbon monoliths (OMCMs). Furthermore, a pharmacokinetic study in rats demonstrated about 2.4-fold increase in oral bioavailability of VAL in the case of HPCM-based formulation compared with the commercially available VAL preparation (Valzaar(®)). These results therefore suggest that HPCM is a promising carrier able to improve the dissolution rate and oral bioavailability of the poorly water-soluble drug VAL.