INVESTIGADORES
RINTOUL Ignacio
congresos y reuniones científicas
Título:
Size-variable mesoporous micro-biobeads for controlled hormone delivery in programmed animal reproduction
Autor/es:
IGNACIO RINTOUL; JUAN MANUEL BADANO; RICARDO GRAU; MARIO WEIBEL
Lugar:
Montpellier
Reunión:
Congreso; EUROMAT 2011. European Congress and Exhibition on Advanced Materials and Processes; 2011
Institución organizadora:
Federation of European Materials Societies, Associazione Italiana di Metallurgia, Société Francaise de Métallurgie et de Matériaux
Resumen:
Selected for oral presentation The control of the estrous cycle and ovulation in bovine breeders significantly improves the livestock cattle business. Controlled hormones release through loaded polymer matrices may control the estrous cycle and artificially induces ovulation. Hormones release from biocompatible, biodegradable and injectable microbeads is an interesting alternative to the existing intravaginal devices. Some advantages of this technology are the possibility to perform massive artificial insemination at very low product and labor costs, to improve the cattle genetics in a fast and economic way and to optimize the delivery periods and the feeding and vaccination programs. In addition, storage, transportation, application and dosage of microbeads are easier than using intravaginal devices. Moreover, aseptic conditions and the actions for introduction, retire and final deposition of intravaginal devices can be avoided.Polyvinyl alcohol, dropping/gelling technique and progesterone were selected as polymer matrix, microencapsulation technology and case hormone, respectively. The effects of chemical composition and dropping/gelling conditions on the geometry and size distribution of microbeads and the dissolution diffusion processes of progesterone through the matrix were studied. A procedure for microbeads production that maximizes the spherical shape, minimizes the polydispersity of results and regulates the pore size for hormone release was developed. Statistical methods were applied for experimental design. The dissolution of progesterone crystals and subsequent diffusion though the polymer matrix was regulated by reversible and irreversible crosslinking at the bulk and surface of the microbeads. The kinetics of progesterone release could be controlled reaching zero order patterns. Those polymeric crosslinking strategies allowed to produce microbeads loaded at 5, 20, 33 and 50 wt% of progesterone. The swelling and the dissolution of the polymer matrix could be varied between 50 to 90% and from 2 hours to 15 days, respectively. Microbeads loaded at 5wt% released progesterone (47mg/L h) at almost double rate than microbeads loaded at 50wt% (20 mg/L h). Invitro and invivo results for hormone release are presented.