Dawnrays Pharmaceutical Holdings Ltd.

Lovastatin and niacin sustained-release tablets containing niacin 500, 750 and 1 000mg, resp., were prepared to investigate the tablets' release characteristics.The release of niacin was determined by the UV method.Effects of HPMC with different viscosity grades on niacin release was also investigated.Orthogonal design of two factors and three levels were used to calculate the theor. amounts of HPMC in different doses of tablets using ANOVA and the stepwise regression anal.To determine the niacin release of three dose tablets, the release actions of tested tablets were compared with the samples abroad through the similar factor method.HPMC K15 MCR was chosen to prepare the tablet core from experimentsThe theor. amounts of HPMC in different doses of tablets were found to be close to the actual amounts, and the niacin release pattern was in accordance with the zero-order equation, and release characteristics of tested tablets were similar to those of the samples abroad.In conclusion the tested tablets has remarkable sustained release property and is easy to prepare

The effects of drug transporters, including P-glycoprotein (P-gp) and multidrug resistance-associated protein (MRP2), on intestinal absorption of breviscapine were studied.Breviscapine concentration in rat intestinal perfusion solution was determined by HPLC.Rat single pass intestinal perfusion (SPIP) was used to study breviscapine intestinal absorption to evaluate the intestinal apparent permeation coefficients (P_app) of breviscapine group and inhibitor group.Based on the statistical anal. of P_App, P-gp inhibitor had no remarkable effects on the intestinal absorption of breviscapine.While for MRP2 inhibitor, P_app was significantly higher than that of the breviscapine group.P-gp transporter has no effect on intestinal absorption of breviscapine, and MRP2 transporter is involved in the intestinal absorption of breviscapine possibly via transporting breviscapine from intestinal epithelium to intestinal cavity.

A HPLC method for determination of clindamycin phosphate and its related substances was established on Lichrospher C₁₈ column (250 mm x 4.6 mm, 5μm) with 0.1 mol L^-1 KH₂PO₄ buffer (adjust pH to 5.6 using 40% KOH solution) acetonitrile, the flow rate of 1.2 mL min^-1 and the detective wavelength at 210 nm.Epiclindamycin phosphate and a unknown impurity could be separated from clindamycin phosphate, but these two impurities were overlapped with clindamycin phosphate according to BP (British Pharmacopoeia) and EP (European Pharmacopoeia) method.The linear range of clindamycin-2-phosphate was 0.1-5.0 mg mL^-1 with r = 0.9996; the linear range of clindamycin B-2-phosphate was 0.0013-0.13 mgmL^-1 with r = 0.9981; the linear range of epiclindamycin-2-phosphate was 0.0014-0.14 mgmL^-1 with r = 0.9972; the linear range of clindamycin was 0.0011-0.11 mgmL^-1 with r = 0.9983.The limit detection was 0.1 μg and the limit quantification is 0.33 μg.The method was more accurate to determination than BP and EP method.