Long-term delivery of testosterone by ALCAP ceramic implants in rats.

The capability of ALCAP ceramic drug-delivery implantable devices to release testosterone for 12 months was investigated. A total of 120 Sprague-Dawley male albino rats were distributed equally into three groups. Two ALCAP capsules, one nonimpregnated and the other impregnated with polylactic acid (PLA) were implanted into each rat in Groups I and II. Capsules implanted into Group I rats were loaded with 40 mg testosterone (T) each. Group II rats were implanted with two empty capsules (sham group), and Group III animals served as unimplanted controls. Eight rats from each group were euthanized at the end of 1, 3, 6, 9, and 12 months following the implantation of the ceramics. No significant changes in the weights of vital organs of rats were observed between any of the three different groups. Vas deferens and epididymal fluid were devoid of normal spermatozoa within 3 months of implanting the steroid-containing ceramics. Testes and epididymis weights decreased significantly in the rats implanted with ALCAP ceramics containing steroid, and the seminiferous tubules became oligospermic after 1 month and azoospermic after 3 months. Circulating levels of both LH and FSH hormones were suppressed in experimental rats. Serum T level was lower than the control but showed no significant difference in comparison to control rats. The data collected in this study suggest that: (a) ALCAP ceramic capsules are capable of delivering T in a sustained manner for 12 months; (b) T delivered by ALCAP capsules can be used effectively to regulate spermatogenesis in rats.