Interrelationship between buffer systems and particle sizes of TCPL drug delivery system

The specific objective of this investigation is to study the effect of tricalcium phosphate delivery system (TCPL) particle sizes on the final density as well as the delivery profiles of various organic compounds in three different buffer environments. Each TCPL matrices were fabricated using three different particle sizes ranges between 1-38, 45-63 and 63-75 microns. The sintered microcrystal material was impregnated with either progesterone (P, 100 mg each) or bovine serum albumin (BSA, 100 mg each). In phase I of the study, each device was suspended in a serum bottle containing 100 mls of ethanol solution (50% wt/vol.) for P release or 100 mls of PBS (pH 7.4) for BSA release. In phase II, similar capsules were suspended in human plasma instead of standard buffers. The vials were agitated at 100 cycle per minute in a water bath set at 37 degrees C. The amount of P or BSA released from the devices into the buffered medium was measured spectrophotometrically. The results of this investigation revealed that a significant difference in the densities of the devices made from the range of individual particle sizes. The rate of steroid hormone and protein released from the devices made from 1-38 micron particle sizes was slower (p < 0.05) than the rate of delivery of P and BSA released from devices fabricated from either 45-63 or 63-75 micron particles. Regardless of the particle sizes effect the results show that the delivery profiles of BSA was higher than the rate of P. This observation could be attributed to the molecular structure as well as the physiochemical characteristics of the drug. In conclusion the data obtained from this study suggest that: (1) Particle sizes variations influence the density of the TCPL delivery system, (2) the rate of release of organic compounds from the ceramic devices is considerably affected by the physiochemical characteristics of medium or buffer system, and (3) the delivery rate of drugs from TCPL devices is directly proportional to the size of the device initial particles and macropores, and inversely proportional to the number of micropores within each device.