RESUMEN
BACKGROUND: Transdermal administration of estradiol offers advantages over oral estrogens for hormone replacement therapy regarding side effects by bypassing the hepatic presystemic metabolism. AIM: The objective of this study was to develop nanoparticles of Chondrosia reniformis sponge collagen as penetration enhancers for the transdermal drug delivery of 17beta-estradiol-hemihydrate in hormone replacement therapy. METHOD: Collagen nanoparticles were prepared by controlled alkaline hydrolysis and characterized using atomic force microscopy and photon correlation spectroscopy. Estradiol-hemihydrate was loaded to the nanoparticles by adsorption to their surface, whereupon a drug loading up to 13.1% of sponge collagen particle mass was found. After incorporation of drug-loaded nanoparticles in a hydrogel, the estradiol transdermal delivery from the gel was compared with that from a commercial gel that did not contain nanoparticles. RESULTS: Saliva samples in postmenopausal patients showed significantly higher estradiol levels after application of the gel with nanoparticles. The area under the curve (AUC) for estradiol time-concentration curves over 24 hours was 2.3- to 3.4-fold higher and estradiol levels 24 hours after administration of estradiol were at least twofold higher with the nanoparticle gel. CONCLUSIONS: The hydrogel with estradiol-loaded collagen nanoparticles enabled a prolonged estradiol release compared to a commercial gel and yielded a considerably enhanced estradiol absorption. Consequently, sponge collagen nanoparticles represent promising carriers for transdermal drug delivery.
Asunto(s)
Colágeno/química , Estradiol/administración & dosificación , Estradiol/farmacocinética , Poríferos/química , Absorciometría de Fotón , Administración Cutánea , Anciano , Animales , Disponibilidad Biológica , Diálisis , Portadores de Fármacos , Electroquímica , Excipientes , Femenino , Humanos , Hidrogeles , Microscopía de Fuerza Atómica , Persona de Mediana Edad , Nanopartículas , Tamaño de la Partícula , Saliva/metabolismo , TermodinámicaRESUMEN
BACKGROUND: Enteric coating prevents oral dose forms from being digested in the stomach, which is required for drugs that are acid unstable, have an irritant effect on the stomach, or are designed to act in the small intestine. AIM: The objective of this study was to develop a novel gastroresistant delayed-release tablet coating based on the marine sponge Chondrosia reniformis Nardo and to investigate the technical feasibility of the coating process. METHOD: An aqueous gastroresistant coating dispersion on the base of freeze-dried sponge collagen 15% (w/w) as the film-forming agent was developed. The disintegration test for gastroresistant tablets (Ph. Eur.) was carried out at increasing coating levels to reveal the required collagen layer thickness. Reproducibility of the method, physical properties, and stability of the coated tablets were investigated. RESULTS: Tablets coated with 13 mg/cm(2) of sponge collagen resisted more than 2 hours to 0.1 M hydrochloric acid, and disintegration of all tablets occurred within 10 minutes in phosphate buffer solution (pH 6.8). The method was reproducible, the mechanical properties of the coated tablets were satisfactory, and the obtained tablets could be stored for at least 6 months without loosing enteric properties. CONCLUSIONS: The novel coating based on the marine sponge collagen (using 12.9 mg/cm(2) coating material) complied with the requirements of Ph. Eur. for gastroresistant tablets. This coating material also meets the regulatory requirements for dietary supplements.