title: In vitro controlled release of bupivacaine from albumin microspheres and a co-matrix formed by microspheres in a poly(lactide-co-glycolide) film.
abstract: Albumin microspheres cross-linked with glutaraldehyde and loaded with bupivacaine, a local anaesthetic, were synthesized (138 +/- 59 microm diameter). A matrix formed by bupivacaine-loaded microspheres in a poly(lactide-co-glycolide) film was prepared in order to improve the controlled release of the drug. In vitro release of the drug was determined in phosphate buffer at 37 degrees C in the absence and in the presence of protease type VIII to mimic a biological system. The effect of temperature and protease on bupivacaine as a function of time was examined; both of them cause a degradative effect on the drug. A rapid release (60 +/- 8% of the drug) takes place at 1 h, and maximum release is found at 50 +/- 6 h from microspheres with swelling. In the presence of protease, maximum release of bupivacaine from microspheres is found at 28 +/- 2 h; the microspheres disappear at 8 days. Inclusion of bupivacaine-loaded microspheres in a poly(lactide-co-glycolide) film causes a slower release of the drug, up to 18 days, with swelling. In the presence of protease, the polymer protects bupivacaine-loaded microspheres from degradation, which takes place at 20 days.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad Complutense de Madrid, Spain.
authors.forename: M V
authors.initials: MV
authors.lastname: Bernardo
authors.forename: M D
authors.initials: MD
authors.lastname: Blanco
authors.forename: C
authors.initials: C
authors.lastname: Gómez
authors.forename: R
authors.initials: R
authors.lastname: Olmo
authors.forename: J M
authors.initials: JM
authors.lastname: Teijón
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D002045:Bupivacaine / Q000008:administration & dosage* / Q000493:pharmacokinetics; D002214:Capsules; D002417:Cattle; D003692:Delayed-Action Preparations; D004339:Drug Compounding; D004355:Drug Stability; D010450:Endopeptidases; D006801:Humans; D066298:In Vitro Techniques; D019344:Lactic Acid; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers; D012710:Serum Albumin, Bovine
chemical_list: D001672:Biocompatible Materials; D002214:Capsules; D003692:Delayed-Action Preparations; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D012710:Serum Albumin, Bovine; D019344:Lactic Acid; D010450:Endopeptidases; D002045:Bupivacaine