Effects of Microemulsion Conditions on Drug Encapsulation Efficiency of Salicylic Acid in Poly(lactide-co-glycolide) Microparticles

摘要

Various microemulsion generation conditions in emulsion solvent evaporation technique can affect the encapsulation efficiency of a drug. In this study, homogenization speed, homogenization temperature and organic-to-aqueous phase ratio were varied and the resulting encapsulation efficiency of a model hydrophobic drug i.e., salicylic acid, in poly(lactide-co-glycolide) (PLGA) microparticles was determined using UV spectrophotometry. Results showed that the encapsulation efficiency of salicylic acid ranged from 8.5 to 17 % depending on the microemulsion conditions. Under the same temperature (15 °C) and homogenization speed (19000 rpm) conditions studied, a relatively high organic-to-aqueous phase ratio (1:5) provided salicylic acid loaded PLGA microparticles with significantly higher drug encapsulation efficiency. In addition, under all microemulsion conditions, PLGA microparticles obtained were spherical and aggregation between the particles was not observed. This indicates that PLGA microparticles with desirable amount of drug and with anticipated size and shape could be realized by controlling emulsification process conditions.