ABSTRACT
Objective To optimize the preparation technology for Centella asiatica total glucosides (CTG) liposome and to investigate its percutaneous permeability in vitro. Methods Liposomes were prepared by reverse-phase evaporation technique. Taking the entrapment efficiency of madecassoside and asiaticoside as indexes, the preparation of liposome was optimized by using single factor and Box-Behnken response surface method. The properties of liposomes including morphology, entrapment efficiency, mean diameter, Zeta potential, and accumulative release were studied. Results The optimal formulation was lecithin-cholesterol (4:1), lecithin-CTG (23.22:1), and organic- aqueous (7:1). The liposome was smooth and spherieal in appearance, mean diameter, and Zeta potential were 201.7 nm and -15.7 mV, respectively. The entrapment efficiency of madecassoside and asiaticoside were 75.85% and 84.94%. The in vitro 12 h accumulative release was 52.10% and 45.97%. The equations for the permeation rate of madecassoside and asiaticoside in liposomes were Q = 67.93 t1/2-50.34, R2 = 0.988, Q = 139.74 t1/2-241.2, R2 = 0.987, respectively. The retention amount in the skin was 76 μg/cm2 and 48.7 μg/cm2, which were 1.56 and 1.18 times higher than those of solution. Conclusion The optimized process is rational, feasible, and good stability. The CTG liposome prepared in this study have the smaller size, the higher encapsulation efficiency, higher retain in skin and obvious sustained-release effects.
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Objective To prepare the ephedrine chitosan-modified liposomes gels, detect the particle diameter and the entrapment efficiency, and investigate the transdermal diffusion characteristics in vitro. Methods Ephedrine liposomes suspensions were prepared using thin film evaporation and slowly dropped by 0.35% chitosan solution with pH values 5-6 in order to prepare the chitosan-modified liposomes gels. The particle diameter of the modified liposomes was detected by Laser Scattering Particle Size Distribution Analyzer. The entrapment efficiency was determined by reverse dialysis method with HPLC. Using Franz Diffusion Cell to investigate transdermal diffusion characteristics of the modified liposomes gels in vitro. Results The mean particle diameter of the modified liposome prepared was from 1 400 to 1 900 nm. The average entrapment efficiency of the modified liposomes was up to (41 ± 0.94)%. Ephedrine in the modified liposomes could penetrate rat skin. The results of the transdermal diffusion test showed the cumulative penetration amount of the ephedrine chitosan-modified liposomes gels was lower than that in the ephedrine solutions with time variation. Conclusion This preparatiom is prepared with simple technology and stable character. The entrapment efficiency of the ephedrine is higher and the assay method is simple and accurate. The penetrating rate of ephedrine is slow and the drug releasing is stable.
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0.05).While compared with the control,the permeation enhancement effects of 5% concentration of Lecithin,Oleic acid,Menthol,Limonene,and Azone were 1.37,2.25,3.71,6.75,and 10.15 times,respectively.CONCLUSION: Compared with Simomenine Hydrochloride,Simomenine free base had excellent transdermal characteristics,and was more suitable for the development of new transdermal preparation.