Pharmacologic response of a controlled-release PLGA formulation for the alpha-melanocyte stimulating hormone analog, melanotan-I

Citation
R. Bhardwaj et al., Pharmacologic response of a controlled-release PLGA formulation for the alpha-melanocyte stimulating hormone analog, melanotan-I, PHARM RES, 17(5), 2000, pp. 593-599
Citations number
23
Categorie Soggetti
Pharmacology & Toxicology
Journal title
PHARMACEUTICAL RESEARCH
ISSN journal
07248741 → ACNP
Volume
17
Issue
5
Year of publication
2000
Pages
593 - 599
Database
ISI
SICI code
0724-8741(200005)17:5<593:PROACP>2.0.ZU;2-5
Abstract
Purpose. The objective of this study was to evaluate in vitro and in vivo t he melanogenic activity of one-month duration Melanotan-I (MTI) implants pr epared using poly (D,L lactide-co-glycolide) polymer. Methods, The biological activity of the samples of MT-I released in vitro f rom the non-irradiated or gamma irradiated implants was measured using a fr og skin bioassay. The effect of MT-I on skin pigmentation was measured usin g a Chroma meter (reflectometer) after subcutaneous administration of impla nts containing 4 mg MT-I to guinea pigs. Eumelanin, the black/brown melanin pigment, was quantified in skin biopsies as pyrrole-2, 3, 5-tricarboxylic acid using HPLC. Results. The MT-I released in vitro from implants after 24 hours exhibited 100% melanotropic activity in frog skins compared to an identical concentra tion of a freshly prepared MT-1 standard. The reflectance readings demonstr ated a prolonged skin darkening for up to three months as evidenced by the decrease in the luminance values from 0 to -4.82, A 2.5-fold increase in eu melanin levels was observed after one month and the increased pigmentation lasted for 3 months. Conclusions, The melanogenic response to MT-I implants persisted for three months and the increase in pigmentation, especially the increased eumelanin levels, could provide protection from ultraviolet radiation.