Haddadi Azita, Aboofazeli Reza, Erfan Mohammad, Farboud Effat Sadat
Shaheed Beheshti University of Medical Sciences and Health Services, School of Pharmacy, Tehran, Iran.
J Microencapsul. 2008 Sep;25(6):379-86. doi: 10.1080/02652040802000714.
This study describes the formulation and characterization of O/W and W/O creams containing urea-loaded microparticles prepared with poly (D, L-lactic-co-glycolic acid) (PLGA) in order to encapsulate and stabilize urea. The solvent evaporation method was used for preparing PLGA microparticles containing urea. The microparticles size was evaluated by laser light diffractometry. The resulting microparticles were then incorporated in O/W and W/O creams and stability and the release pattern from the creams was evaluated by UV-spectrophotometry. The particle size of PLGA microparticles was in the range of 1-5 microm and most microparticles had a particle size smaller than 3 microm. The encapsulation efficiency was calculated as 40.5% +/- 3.4. This study also examined release pattern of urea which varied among different formulations. The results showed that the release from O/W creams followed Higuchi kinetics while the release from W/O creams showed the zero order kinetics and the creams containing microparticulated urea had slower release than free urea creams.
本研究描述了含载有尿素的聚（D，L-丙交酯-乙交酯）（PLGA）制备的微粒的水包油（O/W）和油包水（W/O）乳膏的配方及特性，以便包封和稳定尿素。采用溶剂蒸发法制备含尿素的PLGA微粒。通过激光衍射法评估微粒大小。然后将所得微粒加入O/W和W/O乳膏中，并通过紫外分光光度法评估乳膏的稳定性和释放模式。PLGA微粒的粒径范围为1-5微米，大多数微粒的粒径小于3微米。包封率计算为40.5%±3.4。本研究还考察了不同配方中尿素的释放模式。结果表明，O/W乳膏的释放遵循Higuchi动力学，而W/O乳膏的释放呈现零级动力学，且含微粒化尿素的乳膏比游离尿素乳膏的释放更慢。
