Sustained Pharmacological Activities in Rats Following Single and Repeated Administration of Once-a-Month Injectable Microspheres of Leuprolide Acetate
- 1 January 1991
- journal article
- Published by Springer Nature in Pharmaceutical Research
- Vol. 08 (5) , 584-587
- https://doi.org/10.1023/a:1015844421319
Abstract
Once-a-month injectable microspheres of leuprolide acetate prepared with copoly(DL-lactic/glycolic acid) using an in-water drying method were assessed for duration of the analogue release and pharmacological effects in rats after a single or repeated injection. The periodic challenge test revealed that a single injection of the microspheres caused a dramatic and persistent suppression of the ability of the pituitary–gonadal system to secrete gonadotropin and testosterone for over 5 weeks. The complete recovery of these functions was observed 10 weeks after the injection. The repeated injection of the microspheres at intervals of 2 or 4 weeks achieved persistent suppression of steroidogenesis after an initial transient flare-up and beneficially avoided the “acute-on-chronic response.” This depot formulation is expected to assure patient compliance and produce stronger therapeutic effects than the daily solution.Keywords
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