Formulation and stability studies of metformin hydrochloride in a controlled porosity osmotic pump system

This study was designed to formulate, for the first time, metformin hydrochloride (MH, 850 mg/tablet) as a controlledporosity osmotic pump (CPOP) system to achieve zero-order release pattern. MH core tablet was coated with celluloseacetate membrane containing PEG 400. The effect of different percentages and molecular weights of polyethyleneoxide (PEO, 900K and 4M) in tablet core was studied. The United States Pharmacopeia (USP) apparatus II andphosphate buffer pH 6.8 were used for the release studies; meanwhile, a promising formula was tested in biorelevantmedia. The stability of some selected formulations was carried out for 6 months, at bench and accelerated conditions.Evaluation included: MH content, Differential scanning calorimetry (DSC), Scanning electron microscopy (SEM),drug release, and kinetics. Results revealed that increasing PEO percentage within the core decreased MH release.SEM verified formation of pores in the membrane that accounts for MH release. Almost all stored tablets werestable for all studied parameters. MH endothermic peak maintained its position and energy of enthalpy on storageas confirmed by DSC. MH release rate from a promising formula, following zero-order release model, increased by28% in biorelevant media compared to phosphate buffer. Subsequently, in vitro release in biorelevant media could beemployed as a tool to anticipate in vivo tone of CPOP formulations

Preparation and in vitro evaluation of pregabalin controlled porosity osmotic pump tablets / 中国药科大学学报

@#In this study, pregabalin controlled porosity osmotic pump tablets which are taken once a day were prepared. Single-factor tests were carried out to investigate the influence of excipients and manufacturing process. The formulation was optimized through orthogonal experiment on three levels of three significant factors including the amount of sodium citrate, and polyethylene glycol 400 and coating weight gain. On the basis of the results of the single-factor tests and the orthogonal experiment, optimal formulation and manufacturing process were obtained. The final tablet formulation contained pregabalin(82. 5 mg), microcrystalline cellulose(40%), sodium citrate(27. 5%), magnesium stearate(0. 5%)and 5% povidone K30 solution as the tablet binder; the coating formulation consisted of cellulose acetrate and 60% of polyethylene glycol 400 as a porogen; the coating weight gain was 3%. In vitro drug release kinetic study suggested that the drug release from controlled porosity osmotic pump tablets was mainly driven by osmotic pressure, which was barely affected by the pH of the release medium. The drug release behavior of the tablets within 12 hours complied with zero-order release rule and the linear correlation coefficient was 0. 991 6. The obtained porosity osmotic pump tablets could effectively slow the drug release rate, reduce concentration fluctuation and improve the safety and convenience for the patients, hence with broad prospects.

Formulation optimization of Kyllinga brevifolia total flavonols solid dispersion controlled porosity osmotic pump tablets / 中草药

Objective: To prepare Kyllinga brevifolia total flavonols (KBTF) solid dispersion controlled porosity osmotic pump tablets, and investigate the effects of core tablets and coating on its in vitro drug release behavior, so as to optimize the formulation. Methods: Using KBTF solid dispersion prepared by solvent method as drug core to increase the dissolution of KBTF in vitro, the optimal forrmulation of KBTF solid dispersion controlled porosity osmotic pump tablets was selected via the single factor investigation and orthogonal design. Results: The optimal formula was as follows: osmotic promoter was sodium chloride 100 mg, content of PEG 400 was 150%, content of DBP was 20%, and rate of weight growth of coating membrane was 2%. Conclusion: KBTF solid dispersion controlled porosity osmotic pump tablets with optimal forrmulation can stably release drugs in 12 h and the accumulative drug release rate was more than 90%, whilst its in vitro drug release behavior was up to the character of zero-order drug release.

Preparation and dissolution test in vitro of matrine controlled porosity osmotic pump tablet / 中成药

AIM: To study prescription and process of matrine controlled porosity osmotic pump tablet (matrine CPOPT) and to inspect release property in vitro. METHODS: The orthogonal experiment was designed to screen prescription and process which were definited with the evaluation of release of tablet. RESULTS: The optimization of prescription was definited: osmotic agent consisted of mannitol and lactose with a ratio of 1 ∶ 1(g/g); weight of osmotic agent was 2 fold increase of matrine; the cellulose acetate in coating liquid accounted for 15% (g/g) of PEG 400; The release behavior of matrine CPOPT was coincident with zero-order rate equation well and characteristic of controlled-release. CONCLUSION: Matrine CPOPT has good controlled-release in vitro effect and experiments for further in vivo test are available.

Preparation and Drug Release Mechanism of Tetramethylpyrazine Phosphate Porosity Osmotic Tablet / 中国药房

OBJECTIVE:To prepare Tetramethylpyrazine phosphate porosity osmotic tablet (TMPP) and to optimize its formulation and investigate its mechanism of drug release. METHODS: The formulation was optimized by the orthogonal experiment design through investigation of one factor; the accumulative drug release rates of preparations of different formulation were measured, and the mechanism of drug release of the tablets was discussed. RESULTS: The dosage of PEG 400 in coating solution, the content of hydroxy-propyl methyl cellulose (HPMC) in tablet core, the dosage of dibutylphthalate as plasticizer, and the weight gain of coating membrane were four important factors influencing drug release. The optimal formulation was to use 10% of PEG400, 5% of HPMC, 10% of dibutylphthalate and 12 mg coating membrane. The release behavior in vitro of the porosity osmotic tablets prepared in the above condition within 10 h complied with zero order release rule(r=0.999 81), with accumulative release rate of 94.2%. The tablets had good reproducibility in interassay and which was independent of the influence of gastrointestinal condition. The mechanism of drug release included osmotic pump mechanism and diffusion mechanism, but osmotic pump one was the main type. CONCLUSION: The formulation and preparation technology of the porosity osmotic tablets were simple but effective, showing an obvious zero order release within 12 h and good reproducibility, thus suitable for the industrial production of porosity osmotic tablets.