title: Polyisoprene matrix for progesterone release: in vitro and in vivo studies.
abstract: Latex, a polyisoprene (PI) hydrophobic elastomer, was evaluated in vitro and in vivo as a matrix for intravaginal steroid hormone delivery. Matrices containing hormone were prepared by swelling latex in chloroform that contained soluble progesterone (P4). In vitro studies demonstrate that P4 release from PI follows a zero order model during at least 100 h and depends on initial load up to 10 mg cm(-2). The release of P4 from a PI matrix was found to be two times faster than from a polydimethylsiloxane (PDMS) matrix. FT-IR and X-ray powder diffraction analysis of P4 polymorphs show that when nucleated in PDMS, the hormone crystallizes only in alpha-form while in latex, crystallizes as a mixture of alpha- and beta-form. In vivo studies show that devices with a PI matrix containing 0.5 g of P4 are effective to reach plasma levels above 1 ng ml(-1) that are needed to synchronize estrous in cattle. Altogether, the results show that PI, a vulcanized polymer with a carbon-carbon backbone, can be used as a new matrix for the intravaginal administration of progesterone with improved release profile than silicone and that the matrix can influence the crystalline state of the hormone.
authors.affiliation: Centro de Excelencia en Productos y Procesos de Córdoba (CEPROCOR), Ministerio de Ciencia y Tecnología de Córdoba, Pabellón CEPROCOR, CP 5164, Santa María de Punilla, Córdoba, Argentina.
authors.forename: V
authors.initials: V
authors.lastname: Heredia
authors.forename: I D
authors.initials: ID
authors.lastname: Bianco
authors.forename: H
authors.initials: H
authors.lastname: Tríbulo
authors.forename: R
authors.initials: R
authors.lastname: Tríbulo
authors.forename: M Ferro
authors.initials: MF
authors.lastname: Seoane
authors.forename: S
authors.initials: S
authors.lastname: Faudone
authors.forename: S L
authors.initials: SL
authors.lastname: Cuffini
authors.forename: N A
authors.initials: NA
authors.lastname: Demichelis
authors.forename: H
authors.initials: H
authors.lastname: Schalliol
authors.forename: D M
authors.initials: DM
authors.lastname: Beltramo
mesh_terms: D000282:Administration, Intravaginal; D000818:Animals; D002417:Cattle; D002626:Chemistry, Pharmaceutical; D003460:Crystallization; D018360:Crystallography, X-Ray; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D004337:Drug Carriers; D004339:Drug Compounding; D004973:Estrus Synchronization / Q000187:drug effects; D005260:Female; D005300:Fertility Agents, Female / Q000008:administration & dosage* / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics; D007840:Latex / Q000737:chemistry*; D010052:Ovariectomy; D033362:Powder Diffraction; D011374:Progesterone / Q000008:administration & dosage* / Q000097:blood / Q000737:chemistry / Q000493:pharmacokinetics; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D013678:Technology, Pharmaceutical / Q000379:methods
chemical_list: D004129:Dimethylpolysiloxanes; D004337:Drug Carriers; D005300:Fertility Agents, Female; D007840:Latex; D011374:Progesterone