Benghuzzi H, Possley R, England B
University of Mississippi Medical Center, Jackson 39216.
Biomed Sci Instrum. 1994;30:187-95.
Tricalcium-phosphate-lysine delivery systems (TCPL) have been developed to release pharmaceuticals into the circulation, at a predictable rate, for prolonged periods of time. The objective of this study was to design an implantable TCPL system capable of delivering progesterone (P) for about two weeks and Estradiol (E) in a short burst that mimics the ovulatory surge in adult ewes. TCPL implants were fabricated in four different sizes (1.5, 2.3, 3.5, or 5.6 cm) using four different ceramic compositions and impregnated with P (20-45%) and E (4-16%). Each single device was inserted subcutaneously into the axillary space of adult ewes. Serum P levels were elevated within 2 days postimplantation reaching peak levels of 2.8 ng/ml, 2.3 ng/ml, 1.8 ng/ml and 3.5 ng/ml which then declined to basal levels after 7, 9, 12 and 21+ days in each of the four animals, respectively. Peak serum E levels of 32 pg/ml, 13 pg/ml, 12 pg/ml and 55 pg/ml were obtained in each of the four animals, respectively. Serum E levels initially increased at 7, 9, 7, and 5 days after placement of the implants, and declined to basal levels after 9, 19, 14 and 21+ days in each of the four animals, respectively. Maintenance of low levels of luteinizing hormone (LH) during the time of release of P in the animals shows that the steroid released from the ceramic implants has a negative feedback effect on LH.(ABSTRACT TRUNCATED AT 250 WORDS)
磷酸三钙-赖氨酸递送系统（TCPL）已被开发出来，可将药物以可预测的速率长时间释放到循环系统中。本研究的目的是设计一种可植入的TCPL系统，该系统能够在成年母羊中以模拟排卵高峰的短脉冲方式释放孕酮（P）约两周，并释放雌二醇（E）。使用四种不同的陶瓷成分制造了四种不同尺寸（1.5、2.3、3.5或5.6厘米）的TCPL植入物，并分别浸渍了P（20 - 45%）和E（4 - 16%）。将每个单个装置皮下植入成年母羊的腋窝空间。植入后2天内血清P水平升高，达到峰值水平2.8 ng/ml、2.3 ng/ml、1.8 ng/ml和3.5 ng/ml，然后在四只动物中分别于7、9、12和21 +天后降至基础水平。四只动物的血清E峰值水平分别为32 pg/ml、13 pg/ml、12 pg/ml和55 pg/ml。植入后，血清E水平在7、9、7和5天开始升高，并在四只动物中分别于9、19、14和21 +天后降至基础水平。在动物释放P期间促黄体生成素（LH）维持在低水平，这表明从陶瓷植入物释放的类固醇对LH有负反馈作用。（摘要截断于250字）
