title: Characterization of pilocarpine-loaded chitosan/Carbopol nanoparticles.
abstract: Patients using ophthalmic drops are faced with frequent dosing schedules and difficult drop instillation. Therefore, a long-lasting pilocarpine-loaded chitosan (CS)/Carbopol nanoparticle ophthalmic formulation was developed. The physicochemical properties of the prepared nanoparticles were investigated using dynamic light scattering, zeta-potential, transmission electron microscopy, Fourier transform infrared ray spectroscopy (FT-IR) and differential scanning calorimetry (DSC). The sustained-release effects of pilocarpine-loaded nanoparticles were evaluated using in-vitro release and in-vivo miotic tests, and compared with pilocarpine in solution, gel and liposomes. We found that the prepared nanoparticles were about 294 nm in size. DSC and FT-IR studies suggested that an electrostatic interaction between CS and Carbopol contributes at least in part to the stabilization of pilocarpine/CS/Carbopol nanoparticles. When compared with pilocarpine in solution, gel or liposomes, the best slow-release profile of pilocarpine from the prepared nanoparticles occurred in a dissolution test. In the in-vivo miotic study, pilocarpine-loaded CS/Carbopol nanoparticles showed the most significant long-lasting decrease in the pupil diameter of rabbits. The advantages of CS and Carbopol are good biocompatibility, biodegradability and low toxicity. CS is also a mucoadhesive polymer. Thus, pilocarpine/CS/Carbopol nanoparticles may provide an excellent potential alternative ophthalmic sustained-release formulation of pilocarpine for clinical use. CS/Carbopol nanoparticles may also be useful for a variety of other therapeutic delivery systems.
authors.affiliation: Department of Pharmacy, Chia Nan University of Pharmacy and Science, Tainan, Taiwan.
authors.forename: Huei-Jen
authors.initials: HJ
authors.lastname: Kao
authors.forename: Hong-Ru
authors.initials: HR
authors.lastname: Lin
authors.forename: Yu-Li
authors.initials: YL
authors.lastname: Lo
authors.forename: Shi-Ping
authors.initials: SP
authors.lastname: Yu
mesh_terms: D000180:Acrylic Resins; D000818:Animals; D002152:Calorimetry, Differential Scanning; D048271:Chitosan / Q000737:chemistry*; D003692:Delayed-Action Preparations; D005782:Gels; D008081:Liposomes; D046529:Microscopy, Electron, Transmission; D008916:Miotics / Q000008:administration & dosage* / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry / Q000648:ultrastructure; D009883:Ophthalmic Solutions; D010316:Particle Size; D010862:Pilocarpine / Q000008:administration & dosage* / Q000737:chemistry; D011145:Polyvinyls / Q000737:chemistry*; D011680:Pupil / Q000187:drug effects / Q000502:physiology; D011817:Rabbits; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000180:Acrylic Resins; D003692:Delayed-Action Preparations; D005782:Gels; D008081:Liposomes; D008916:Miotics; D009883:Ophthalmic Solutions; D011145:Polyvinyls; D010862:Pilocarpine; C006912:carboxypolymethylene; D048271:Chitosan