Hydroxyapatite-oil composites for delivering AZT in simulated body fluid.

Hydroxyapatite (HA) has been used to deliver therapeutic drugs both in vitro and in vivo at a constant rate showing zero order kinetics. This study was designed specifically to analyze the effects of wheat germ (WG) incorporation with HA on the rate of delivery of AZT from an insert system over a one month period in vitro. Insert systems which were saturated with wheat germ oil delivered AZT at a slower rate over the one month period than did half-saturated or unsaturated insert systems. All systems containing 50 mg of AZT in the outer shell delivered 80% of the 100 mg AZT dosage over the first eight days. The systems which had a 100 mg AZT insert surrounded by an oily HA shell lacking AZT delivered AZT in a linear manner over the course of one month. The amounts and rates of AZT release from composites was indirectly proportional to the amount of wheat germ oil used. The results of this study show that the lipids incorporated in the ceramic composites can be tailored to deliver a 100 mg AZT dosage for a period of one month in vitro.