Development of a ceramic matrix system for continuous delivery of azidothymidine

A beta-tricalcium phosphate (TCP) ceramic system was designed to deliver azidothymidine (AZT) in an aqueous medium (phosphate buffered saline pH 7.4) at 37 degrees C. Since AZT is an analog of thymidine, initial studies were conducted with thymidine. Ceramic capsules were made by pressing one gram of < 38 microns beta-TCP particles with or without the desired amount of thymidine or azidothymidine in a 10 mm die at a load of 4000 lbs in an electric hydraulic press. The amount thymidine released from TCP ceramic capsules was directly dependent on the amount of the drug loaded in the ceramic. Treatment of TCP ceramic particles with either sesame seed oil or wheat germ oil (vitamin E) delayed the release of thymidine and azidothymidine from TCP ceramic capsules. Incorporation of thymidine or azidothymidine in the form of a compressed pellet (5/16" diameter at a load of 4000 lbs) further inhibited the release of thymidine and azidothymidine from TCP ceramic capsules fabricated with oil-treated ceramic particles. Thus, ceramic drug delivery systems can be designed to deliver continuously desired therapeutic levels of AZT in AIDS patients.