The Use of Cellulose Membrane to Eliminate Burst Release from Intravaginal Rings.
Burst release was observed when ethylene vinyl acetate copolymer (EVA) intravaginal rings were tested for progesterone release in our previous work (Helbling et al. Pharm Res. 31(3):795-808, 2014). Burst release is undesirable in controlled delivery devices because release is uncontrollable and higher levels of active pharmaceutical ingredient could lead to the occurrence of adverse effect. The present contribution is about the use of membranes to coat EVA rings to eliminate burst release. Physicochemical state of progesterone in uncoated rings and the solubility and diffusion coefficient in membrane were studied. Hormone delivery from several rings of different sizes was compared. A mathematical model was used to analyze the effects of membrane properties on delivery rate. No chemical interactions were detected between hormone and polymer. Hormone was mainly forming amorphous aggregates inside rings, and migration to membrane was not observed during storage. Diffusion coefficient was smaller in membrane (∼10(-8) cm(2) s(-1)) than in matrix (∼10(-7) cm(2) s(-1)). Zero-order release kinetics were obtained for coated rings, and release rate decreases as the thickness of the coat increases. Cellulose membrane successfully eliminates burst release and controls the delivery from EVA rings. The equations developed can be used to determine the appropriate coat thickness to produce specific release rate.
Laboratorio de Química Fina, Instituto de Desarrollo Tecnológico para la Industria Química (INTEC), Universidad Nacional del Litoral and Consejo Nacional de Investigaciones Científicas y Técnicas (UNL-CONICET), CCT CONICET-SANTA FE, Ruta Nacional 168, Paraje El Pozo, 3000, Santa Fe, Argentina. ihelbling@santafe-conicet.gov.ar.
Ignacio M
IM
Helbling
Laboratorio de Química Fina, Instituto de Desarrollo Tecnológico para la Industria Química (INTEC), Universidad Nacional del Litoral and Consejo Nacional de Investigaciones Científicas y Técnicas (UNL-CONICET), CCT CONICET-SANTA FE, Ruta Nacional 168, Paraje El Pozo, 3000, Santa Fe, Argentina.
Juan C D
JC
Ibarra
Laboratorio de Química Fina, Instituto de Desarrollo Tecnológico para la Industria Química (INTEC), Universidad Nacional del Litoral and Consejo Nacional de Investigaciones Científicas y Técnicas (UNL-CONICET), CCT CONICET-SANTA FE, Ruta Nacional 168, Paraje El Pozo, 3000, Santa Fe, Argentina.
Julio A
JA
Luna
D002482:Cellulose; D003692:Delayed-Action Preparations; D007700:Kinetics; D011145:Polyvinyls / Q000737:chemistry*; D012995:Solubility
D003692:Delayed-Action Preparations; D011145:Polyvinyls; D002482:Cellulose
burst release; cellulose membrane; drug delivery; intravaginal rings; progesterone