Buserelin

Mechanism (as reported)

A study described buserelin as a GnRH agonist whose stimulation of pituitary gonadotrophin release is followed by reversible pituitary desensitisation with blockade of gonadotrophin support to the gonads. PMID(s): 2109679. Another source reported that prolonged buserelin administration produces a selective and durable inhibition of pituitary gonadotropin secretion, leading to medical castration. PMID(s): 2506941.

Key findings (each cites a source)

• Research investigated buserelin degradation under dry heat/solid-state heat stress using a stability-indicating UPLC-PDA method, with kinetic model fitting (Ginstling-Brounshtein reported as best fit) and mass spectrometric identification of buserelin-related degradants. PMID(s): 24657556 [PMID 24657556]
• A study reported that dry heat exposure of solid buserelin generated degradants, and proposed multiple degradation hypotheses including: β-elimination and fragmentation; internal esterification followed by β-elimination or hydrolysis; direct backbone hydrolysis; and isomerisation of peptide fragments and buserelin itself. PMID(s): 24657556 [PMID 24657556]
• A review reported that buserelin is a GnRH agonist/analog and described that a single dose stimulates pituitary gonadotrophins, while multiple doses produce reversible pituitary desensitisation and blockade of gonadotrophin support to the gonads as a basis for use in sex-hormone dependent conditions. PMID(s): 2109679 [PMID 2109679]
• A review article reported that buserelin shows use across gynaecology/andrology/paediatrics/oncology and includes mentions of conditions such as endometriosis, uterine leiomyoma, precocious puberty, and sex-hormone dependent cancers, along with general statements about adverse effect patterns (e.g., hypoestrogenic effects described). PMID(s): 2109679 [PMID 2109679]
• A study in pigs reported that buccal administration of buserelin produced rapidly reached steady-state plasma levels, and that co-administration of glycodeoxycholate increased absolute bioavailability compared with buccal delivery without the enhancer (values reported in the source). PMID(s): 8865318 [PMID 8865318]
• A source described buserelin as a synthetic GnRH analog more potent than natural GnRH and reported that prolonged administration leads to selective/durable inhibition of pituitary gonadotropin secretion following an initial short stimulation phase. PMID(s): 2506941 [PMID 2506941]
• A review discussed buserelin in prostatic cancer, reporting that studies (pilot and controlled) showed response rates similar to diethylstilbestrol or orchiectomy in palliative treatment of advanced prostatic cancer, while noting the need for larger/better designed studies. PMID(s): 2506941 [PMID 2506941]
• A source described commonly reported adverse effects in the context of prostatic cancer treatment with buserelin (e.g., loss of libido/impotence, hot flushes, and possible flare-up of carcinoma symptoms early in therapy). PMID(s): 2506941 [PMID 2506941]
• A review on fibroid management described the literature on use of GnRH agonists and related interventions as alternatives to hysterectomy (buserelin included as part of the GnRH agonist class discussed). PMID(s): 1535799 [PMID 1535799]