ABSTRACT
Objective: To prepare the rhynchophylline nanosuspensions and lyophilized powder, and study its sustained-release tablets. Methods: Rhynchophylline nanosuspensions were prepared by microprecipitation combined with high pressure homogenization method, and the particle size and zeta potential were determined. Scanning electron microscopy (SEM) was employed to observe the appearances of nanosuspensions. Nanosuspensions were prepared into lyophilized powder using lactose as freeze-dried protectors. HPMC (hydroxypropyl methyl cellulose) was used as hydrophilic matrix to prepare the sustained-release tablets. Single factor investigation and orthogonal experiments were employed to optimize the formulation of rhynchophylline nanosuspensions sustained-release tablets, and the model fitting was also been studied. Results: The particle size and zeta potential of rhynchophylline nanosuspensions were (153.7 ± 4.9) nm and (-18.54 ± 1.32) mV, respectively. The appearances of rhynchophylline nanosuspensions were spherical or nearly spherical. After orthogonal optimization, the cumulative release rate of rhynchophylline nanosuspensions sustained-release tablets was 92.53% in 12 h. The optimized formulation of hydrogel matrix sustained-release tablets was better accorded with Higuchi model: ln(1-Mt/M∞)=0.286 0 t1/2-0.069 0 (r=0.992 4). The drug release from hydrogel matrix sustained-release tablets were controlled by diffusion and degradation. Conclusion: The obtained rhynchophylline nanosuspensions has small particle size. The prepared hydrogel matrix sustained-release tablets can control the release of rhynchophylline nanosuspensions in a slow characteristic.
ABSTRACT
OBJECTIVE： To optimize the formulation of Diosmin gel and to investigate its in vitro release property. METHODS： Diosmin gel were prepared by using Carbomer 940 as matrix. Using accumulative release rate as index， with the amount of Carbomer 940， ethanol， acetone and pH as factors， L9（34） orthogonal test was conducted. The formulation of Diosmin gel was optimized and validated. Using Diosmin ointment as reference， dialysis bag diffusion method was used to investigate in vitro release property of Diosmin gel prepared by optimal formulation. RESULTS： The optimal formulation of Diosmin gel included Carbomer 940 1.5 g， ethanol 15 mL， glycerol 8 g， pH 6. The gel prepared with optimal formulation was sticky brown-yellow semi solid， and had good coating and spreading properties. The average accumulative release rate （2 h） was （12.67±0.12）％. Results of drug release test showed that Diosmin gel released rapidly within 12 h， then gradually slowed down. The accumulative release rates were （71.93±0.42）％ （12 h） and （80.47±0.54）％ （24 h）， drug release of which were in line with Higuchi equation. Diosmin ointment was released slowly. The accumulative release rates were （41.74±0.18）％ （12 h） and （62.63±0.59）％ （24 h）. Drug release of it were in line with first-order equation. CONCLUSIONS： The formulation of Diosmin gel is optimized successfully. Prepared Diosmin gel has good drug release property.
ABSTRACT
OBJECTIVE:To optimize the formulation of Mirabegron sustained-release tablets. METHODS:Using polyethylene oxide(PEO)and hydroxypropylmethyl cellulose(HPMC K4M)as the sustained release matrix,Mirabegron sustained-release tab-lets were prepared by powder direct compression technology. Using 1,3,5,7 h accumulative release rate as indexes,the amounts of PEO,HPMC K4M and OPADRY? were optimized by composite design-response surface method,and then validated. Accumula-tive release rates of sustained-release tablet and original tablet (MyrbetriqTM) were compared in different pH mediums (water,pH 1.0 simulated gastric fluid,pH 4.5 acetate buffer solution,pH 6.8 phosphate buffer solution) at different rotation rates (100,50 r/min),and similiar factor f2 was calculated to fit drug release model of sustained-release tablet. RESULTS:In the optimized firmu-lation each Mirabegron sustained-release tablet contained mirabegron 25 mg,PEO 108.02 mg,HPMC K4M 21.69 mg,OPADRY? 2.27%. Relative error of accumulative release rates at 1,3,5,7 h to predicted value were 4.78%,3.48%,0.69% and -1.41%, respectively. f2 of release curves of sustained-release tablet and original tablet were higher than 65 in different pH medium at differ-ent rotation rates. The drug release of sustained-release tablet was fitted to zero-order release equation. CONCLUSIONS:Mirabe-gron sustained-release tablet by optimized technology is similar to original tablet in drug release behavior.
ABSTRACT
OBJECTIVE:To investigate release characteristics of sirolimus liposome in vitro.METHODS:The concentration of sirolimus was determined by RP-HPLC.In vitro release rate of sirolimus liposome within 24 h was investigated by the reverse dialysis method with 20% ethanol 500 mL as medium.Release curve of sirolimus was fitted with drug release model equation.RESULTS:The linear range of sirolimus were 0.5～20 ?g.mL-1(r=0.999 8)with an average recovery of 99.42%(RSD=1.23%).At the first 4 hours of release,sirolimus liposome released rapidly with accumulative release rate of 50%.After that release rate of liposome was slowed down with accumulative rate of 80% in 24 h.The in vitro release curve conformed to the first order equation.CONCLUSION:Sirolimus liposome has delayed release capability,and in vitro drug release of sirolimus liposome is in concentration dependant manner.