Preparation and <i>in Vitro</i>Drug Release Evaluation of Once-Daily Metformin Hydrochloride Sustained-Release Tablets

The objective of this study was to develop once-daily metformin hydrochloride sustained-release tablets (MHSRT) and evaluate their in vitro release behavior. MHSRT were prepared by the film coating method. The in vitro drug release rate of MHSRT and the commercial tablets Fortamet? made in the United States of America in water was fitted with zero order kinetic equation, and Ritger-Peppas kinetic equation in 0.1 M HCl and pH 6.8-phosphate buffer, respectively. The similarity factor f2 values of MHSRT in three different dissolution medium were 82, 80 and 74, respectively in comparison with imported Fortamet?, which were all greater than 50. The results of storage-stability showed that MHSRT were stable for at least 6 months under stress condition (40℃ ± 2℃, RH 75% ± 5%). Therefore, in this study, MHSRT were successfully prepared using optimized formulation technologies that meet mass produce. The in vitro release behavior of MHSRT was almost similar to that of imported Fortamet?.

Preparation and evaluation of sustained-release azithromycin tablets in vitro and in vivo

The objective of this study was to prepare azithromycin(AZI)sustained-release products in order to allow for a high dose to be administered,reduce gastrointestinal side-effects and increase the compliance of patients.AZI sustained-release tablets with different release performance(F-I:T_(100%)=3 h and F-II:T_(100%)=8 h in pH 6.0 phosphate buffer)were successfully prepared by wet granulation.The in vitro release rate and drug release mechanism were studied.The release rate of F-Iwas affected by dissolutionmedia with different pH,but not for F-II.HixsoneCrowellmodel was the best regression fitting model for F-I and F-II.Additionally,F-I and F-II both belonged to non-Fick diffusion.Oral pharmacokinetics of the two tablets and one AZI dispersible tablet as reference were studied in six healthy beagle dogs after oral administration.Compared with the reference,the C_(max) of F-I and F-II were decreased,and the T_(max) were prolonged,in that case which meet the requirement of sustained-release tablets.The relative bioavailability of F-I and F-II were 79.12%and 64.09%.T-test ofAUC_(0-144),and AUC_(0-∞) for F-I and F-II indicated there was no significant difference between F-I and F-II.These mean that the extended release rate did not induce different pharmacokinetics in vivo.

Clinical observation of Baitou Weng Decoction combined with mesalazine sustained-release tablets in treating heat-toxic and smoldering ulcerative colitis

Objective:To observe the clinical efficacy of Baitou Weng Decoction combined with mesalazine sustained-release tablets in the treatment of ulcerative colitis with febrile heat and its effect on immune function and serum inflammatory factors.Methods: A total of 84 patients with ulcerative colitis were randomly divided into control group and treatment group, with 42 cases in each group. The control group was given mesalazine sustained-release tablets orally, while the treatment group was given Baitou Weng Decoction and mesalazine sustained-release tablets orally. The treatment period was 30 days and the patients were followed up for 3 months. After treatment, the clinical efficacy, quality of life, immune function and serum inflammatory factors of the two groups were observed.Results: The effective rate of treatment group (90.47%) was higher than that of control group (73.81%) (P<0.05);compared with before treatment, the scores of inflammatory bowel disease quality of life questionnaire scale in both groups were significantly improved (P<0.05), and the difference between the two groups was significant (P<0.05);after treatment, the plasma CD4+/CD8+ ratio and NK+ levels in both groups were significantly higher than those before treatment (P<0.05), and the treatment group was changed. The serum levels of tumor necrosis factor-α, interleukin-17 and interleukin-23 were significantly decreased in both groups after treatment (P<0.05), and the improvement was more significant in the treatment group (P<0.05). No significant adverse reactions were observed in the treatment group.Conclusions: Modified Baitou Weng Decoction combined with mesalazine in the treatment of heat-toxic and incandescent ulcerative colitis can significantly improve the clinical efficacy, improve the quality of life of patients, effectively regulate the expression level of serum inflammatory factors in ulcerative colitis patients, promote the recovery of patients' immune function, and have high drug safety.

Pharmacokinetic Study on Lovastatin Sustained-release Tablet and Sustained-release Capsule in Begal Dogs

This study pharmacokinetically examined the lovastatin sustained-release tablet and sustained-release capsule in Beagle dogs. An reversed-phase HPLC method was established for the determination of lovastatin in Beagle dog plasma. Pharmacokinetic findings were compared among three preparation(lovastatin sustained-release tablet,T p; sustained-release capsule,T J and conventional capsule). Our results showed that the pharmacokinetic parameters in 6 dogs after single-dose oral administration of three perparations were calculated. T max, C max and MRT revealed significant difference (P<0.05). Relative bioavailability was 111.5±16.9 % (T P) and 110.4%±9.6 % (T J). The pharmacokinetic parameters in the 6 dogs after multiple-dose oral administration of three perparations, T max, C max MRT and DF had significant difference (P<0.05); C av , C min and AUC 0-24 h displayed no significant difference (P>0.05). It is concluded that the lovastatin sustained-release tablet and sustained-release capsule are able to maintain a sustained-release for 24 h.

Simultaneous Analysis of Indapamide and Related Impurities in Sustained-Release Tablets by a Single-Run HPLC-PDA Method

The contents of indapamide and related impurities in generic indapamide sustained-release tablets were simultaneously detected by a single-run high performance liquid chromatography equipped with photodiode array detector(HPLC-PDA)method for the quality control in this paper.The results showed the method had a good selectivity and was validated through linearity,limits of detection and quantification,recovery,and precision.The linear ranges of indapamide,2-methyl-1-nitroso-2,3-dihydro-1H-indole(impurity A,ImA),4-chloro-N-(2-methyl-1H-indol-1-yl)-3-sulphamoyl-benzamide(impurity B,ImB)and 4-chloro-3-sulfamoylbenzoic acid(impurity 1,Im1)were 0.028-1.80μg/mL(R=0.99995),0.060-1.20μg/mL(R=0.9996),0.0324-1.20μg/mL(R=0.99985)and 0.060-1.20μg/mL(R=0.9997)with detection limits of 0.0093,0.012,0.012 and 0.006μg/mL,respectively.ImA and Im1 were not detectable in the generic drug.The content of indapamide was 96.7%of the labeled amount with a relative standard deviation(RSD)of 1.30%,and the percentage of ImB relative to the labeled amounts of indapamide was 0.106%with an RSD of 1.82%.The content of other unspecified impurities all met the reference quality standards.The results provided references for the quality control and the quality standard study of generic indapamide sustained-release tablets.

喘平缓释片释药机制的研究

目的阐明喘平缓释片的释药机制。方法采用转篮法结合HPLC测定喘平缓释片的累计释放率,用零级、一级、Higuchi方程、Peppas方程等释药模型对喘平缓释片的释放曲线进行拟合,从溶出过程中各规定时间点取样测定其溶胀率、溶蚀度,体视显微镜观察缓释片的形态变化。结果喘平缓释片指标成分盐酸麻黄碱和盐酸伪麻黄碱在8 h的累计释放率均达到了80%,基本实现了均衡释放,用Peppas方程进行拟合后的方程分别为lg(Mt/M肄)=0.5108 lgt-0.5562,R2=0.9991,n=0.5108和lg(Mt/M肄)=0.5150 lgt-0.5386,R2=0.9989,n=0.5150。喘平缓释片的溶胀率在药物约释放60%时达到了最大值,其后逐渐下降,而溶蚀度则随着药物累计释放率的增加而增加。从体视显微镜观察到遇水膨胀后的缓释片凝胶层和浸润层在一定时间内是逐渐增厚的。结论喘平缓释片的体外释放机制为药物扩散及骨架溶蚀两种作用。在喘平缓释片的体外溶出实验中,有众多颗粒从片剂表面脱落,提示喘平缓释片释药可能存在着新的释放模式-溶蚀-溶散-扩散机制。

喘平缓释片体外释放与人体内吸收的相关性研究

目的:研究喘平缓释片体外释放与人体内吸收的相关性。方法:以麻黄碱、伪麻黄碱为指标成分,体外采用转篮法结合HPLC测定喘平缓释片在不同pH介质中的累积溶出率;体内采用尿药法结合HPLC测定尿液中的药物浓度;应用Wagner-Nelson法评价喘平缓释片体内外相关性。结果:喘平缓释片人体内不同时间点的吸收百分数F与体外累积溶出率f的线性回归方程分别为F麻黄碱=1.572 5f-20.729(R2=0.974 5),F伪麻黄碱=1.237f-0.147 6(R2=0.959 5)。结论:喘平缓释片体内-体外相关性良好,体外释放度测定方法可用于控制喘平缓释片内在质量和预测其生物利用度。