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.
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Okada, H., Heya, T., Ogawa, Y. et al. Sustained Pharmacological Activities in Rats Following Single and Repeated Administration of Once-a-Month Injectable Microspheres of Leuprolide Acetate. Pharm Res 8, 584–587 (1991). https://doi.org/10.1023/A:1015844421319
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DOI: https://doi.org/10.1023/A:1015844421319