Controlled release of hydrophilic compounds by resorbable and biodegradable ceramic drug delivery devices

Hydroxyapatite (HA), aluminum-calcium-phosphorous oxide (ALCAP), bone meal (BM), and tricalcium phosphate (TCP) ceramic implants are biodegradable and nontoxic to the host. The purpose of this study was to investigate the capability of these ceramics to deliver the catecholamine, epinephrine (EPI) in a sustained and controlled manner. The ceramic powder (less than 38 um particle size) was prepared in our laboratory using standard procedures. Sixteen cylinders were prepared (1 g each) from each of the four ceramic materials. All cylinders were pressed at a compression load of 615 Kg and sintered for 36 hours. ALCAP (group I) and BM (group II) cylinders were sintered at 1400 degrees C and HA (group III) and TCP (group IV) ceramic capsules were sintered at 1150 degrees C. Three capsules from each group were loaded with 30 mg EPI. Capsules containing EPI and control (empty) capsules were each suspended in a serum bottle containing 100 ml of phosphate buffered saline (pH 7.4). The amount of EPI released from each capsule was determined by spectrophotometric methods. Data collected from this study showed that the rate of release of EPI from ALCAP, HA, BM and TCP was 6.14 +/- 0.3 3.55 +/- 0.29, 2.07 +/- 0.26 and 1.17 +/- 0.04 mg/day, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)