title: Hydrophilic gel containing nanocapsules of diclofenac: development, stability study and physico-chemical characterization.
abstract: The purpose of this work was to develop and to characterize hydrophilic gels containing nanocapsules (NC) of diclofenac (DIC). Nanocapsules suspension of poly-epsilon-caprolactone containing free acid diclofenac were prepared by nanoprecipitation. The pH value of the nanocapsules suspension was 5.70 +/- 0.03 and the mean sizes of the NC were in the sub 300 nm range. Drug incorporated into the nanocapsules was close to 100% and the encapsulation efficiency was 104.1% +/- 3.5%. Diclofenac nanocapsules suspension (1 mg/mL) was incorporated in a Carbopol gel matrix fournishing a formulation with 0.5 mg of DIC/g. The gel stability was evaluated in terms of the macroscopic and microscopic aspect, rheological properties, pH and drug recoveries. As a result, we obtained a suitable formulation for topical use presenting a non-Newtonian behaviour with plastic properties and with intact nanostructures in the gel matrix after 3 months storage atroom temperature (freeze-fracture electron microscopy).
authors.affiliation: Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: D
authors.initials: D
authors.lastname: Milão
authors.forename: M T
authors.initials: MT
authors.lastname: Knorst
authors.forename: W
authors.initials: W
authors.lastname: Richter
authors.forename: S S
authors.initials: SS
authors.lastname: Guterres
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage* / Q000737:chemistry*; D002214:Capsules; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003102:Colloids; D004008:Diclofenac / Q000008:administration & dosage* / Q000737:chemistry*; D004355:Drug Stability; D005079:Excipients; D005614:Freeze Fracturing; D005782:Gels; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D012212:Rheology; D013535:Suspensions; D014783:Viscosity
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D002214:Capsules; D003102:Colloids; D005079:Excipients; D005782:Gels; D013535:Suspensions; D004008:Diclofenac