Sustained release of sulfamethizole, 5-fluorouracil, and doxorubicin from ethylcellulose-polylactic acid microcapsules.

The preparation of ethylcellulose-polylactic acid microcapsules with long release half-lives of chemotherapeutic agents was investigated. The microcapsules were prepared by means of coacervation-phase separation of ethylcellulose from ethyl acetate solution by nonsolvent addition in the presence of polylactic acid. In the case of sulfamethizole microcapsules, longer release half-life was obtained with larger amounts of polylactic acid in the preparation. The release rate of sulfamethizole was not very dependent on the pH of the release media. 5-Fluorouracil and doxorubicin hydrochloride were similarly microencapsulated. 5-Fluorouracil microcapsules were sieved prior to release studies. A release half life of 2.6 hr was obtained with the 5-fluorouracil microcapsules. In the case of doxorubicin microcapsules, the drug was released with a half-life of 84 min, whereas uncoated doxorubicin dissolved completely within 15 min.