ABSTRACT
Objective To optimize the formula of konjac glucomannan-paeonol matrix tablets. Methods The formula of paeonol matrix tablets was optimized by the orthogonal design with the accumulative release rate in vitro as index, with the viscosity of konjac glucomannan ( KGM) , the amount of KGM and lactose as influence factors. Results The optimized formula was as follows:the viscosity of konjac glucomannan was 20 000 mPa·s, KGM 30%, lactose 20% and the release in vitro fit into the Higuchi equation. Conclusion The formula of the paeonol matrix tablets is reasonable and the tablets have well release effect in vitro.
ABSTRACT
Pure and drug hydrophilic matrix tablets were prepared by direct compression method with theophylline as a model drug. The characteristics of four hydrophilic matrix polymers, hydroxypropylmethylcellulose (HPMC), polyethylene oxide (PEO), sodium alginate (NaAlg) and xanthan gum (XG), were compared by investigating the water absorption, swelling, erosion and gel layer strength. The sequence of water absorption rate was XG >> NaAlg (H) > PEO > NaAlg (L) >> HPMC; The sequence of swelling index was XG >> PEO >> HPMC >> NaAlg; The sequence of erosion rate was NaAlg (L) > NaAlg (H) >> PEO80 > PEO200 > PEO300 > XG approximately PEO400 approximately K4M > K15M > PEO600 approximately K100M; The sequence of the gel layer strength was PEO > HPMC > XG >> NaAlg. For the PEO and HPMC matrix tablets, with the polymer molecular weight increased, the drug release mechanism was gradually transferred from mainly depending on the erosion to the diffusion; for SAL matrix tablets, the drug release mainly depends on erosion mechanism; and for XG matrix tablets, the drug release mainly depends on non-Fick diffusion mechanism. Comparison of the performance difference between the polymer materials will contribute to rational design and prediction of drug release behaviors from matrix tables and ultimately to achieve clinical needs.
ABSTRACT
OBJECTIVE: To prepare Polylactic-co-glycolic acid)(PLGA) microspheres loaded with Chinese herbal extract cucurbitacin B.METHODS: Cucurbitacin B loaded by PLGA microspheres were prepared by modified emulsification-solvent evaporation method.Central composite design-response surface method was applied to optimize the formulation with PVA concentration and ratio of drug to polymer as independent variables,and with yield of microspheres(Y1),drug loading amount(Y2),encapsulation efficiency(Y3),mean particle diameter(Y4),and the cumulative percentage of the drug release in 24 hr(Y5) as indexes to conduct multiple linear regression and second-order polynomial equation fitting.In vitro release test was performed by modified immediate release method.RESULTS: The results showed that all response variables were greatly fitted by a second-order polynomial equation.The optimal formulation was proved to be as follows: PVA concentration was 0.014 and ratio of drug to polymer was 0.066 5.The microspheres prepared in the optimal formulation were spherical and had smooth surface.Y1,Y2,Y3,Y4,and Y5 were 79.9%,7.83%,80.5%,56.18 ?m and 6.98%,respectively.The cumulative release from microspheres within 35 days reached 86.73%.CONCLUSION: Cucurbitacin B-PLGA microspheres are characterized by prolonged action and sustained-release.Furthermore,the established model has satisfactory predictability.