The effect of various testosterone concentrations released from ceramic delivery systems on the circulating hormone levels of adult castrated rams.
Ceramic delivery systems (CDS) have been found to be useful carriers for chemical and biological materials allowing a constant release of these materials over prolonged periods of time. We reasoned that testosterone (TE) filled CDS could be utilized in the long-term treatment of androgen deficient patients. The specific objective of this study was to investigate the ability of CDS to deliver TE at a sustained level for 90 days using castrated adult rams as a model. Ceramic capsules were fabricated to a final density of 1.72 +/- 0.02 gm/cm3. The sintered capsules were loaded with either 440 mg or 700 mg TE and then sealed at both ends and subsequently sterilized by exposure to ethylene oxide for 24 hours. The TE-filled CDS were then implanted subcutaneously, under the forelimb of yearling rams (body weight; 30-42 Kg). Radiographs of implanted ceramics one week after implantation indicated that the capsules were intact and unaltered. The passage of TE through CDS capsules started within 4 days after implantation. An initial high release of the steroid was noted in all experimental animals which was maintained for up to 12 days post-implantation. After the initial high rate of release the serum concentration of TE remained constant at about 0.35 nM/ml in rams implanted with CDS containing a high TE dose and serum concentrations of approximately 0.21 nM/ml were observed in rams treated with the low dose capsules. There was no significant change in body weight gain between the experimental and castrated control rams.(ABSTRACT TRUNCATED AT 250 WORDS)
England
B G
BG
Department of Pathology, University of Michigan Medical School, Ann Arbor 48109.
Benghuzzi
H A
HA
Possley
R M
RM
Bajpai
P K
PK
D000818:Animals; D002130:Calcium Phosphates; D002369:Castration; D002516:Ceramics; D004334:Drug Administration Schedule; D004343:Drug Implants; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D012756:Sheep; D013739:Testosterone / Q000008:administration & dosage* / Q000097:blood*
D002130:Calcium Phosphates; D004343:Drug Implants; C485817:beta-tricalcium phosphate; D013739:Testosterone; D007986:Luteinizing Hormone; C018392:tricalcium phosphate