ABSTRACT
The rationale for the development of various particulate systems for sustained drug delivery is based on possible entrapment of the particles in the ocular mucus layer covering the eye surface, and the interaction of bioadhesive polymer chains with mucins. Drug-release kinetics are regulated by the composition and preparation procedure of the particles, the molecular weight and degradation of the polymers, and the physicochemical properties of the entrapped drug molecule. The ultimate particle size of the particles and the degree of drug loading are dependent on several preparation parameters such as the pH of the preparation medium and the type of stabilizer or surfactant used. Poly(epsilon-caprolacton) (PECL) nanoparticles and nanocapsules for ophthalmic use can be prepared by solvent extraction or solvent evaporation method. Numerous in vivo studies demonstrated that enhanced corneal absorption and prolonged therapeutic effects of drugs are possible when the drugs are incorporated in PECL nanoparticles.
