title: Preparation and evaluation of liposomal formulations of tropicamide for ocular delivery.
abstract: Tropicamide, a mydriatic, cycloplegic drug was entrapped in liposomes. Liposomes were investigated by laser counting studies, transmission electron microscopy and differential scanning calorimetry for characterization. The precorneal clearance of liposomes was compared with solution by gamma-scintigraphy in the rabbit. The neutral liposomes failed to demonstrate significant enhancement in precorneal retention in comparison with aqueous solution. The potential of liposomes as an ophthalmic drug delivery system was investigated by comparing pupil dilatory effect of tropicamide by topical instillation, in the rabbit eye, of the solution and various drug-loaded liposomal forms, i.e. neutral liposomes, positively charged liposomes and neutral liposomes dispersed in 0.25% (w/v) polycarbophil gel. The positively charged liposomal formulation and liposomes dispersed in polycarbophil gel were found to be more effective than neutral liposomal dispersion when data were statistically treated at the 5% level of significance.
authors.affiliation: Department of Pharmaceutics, Bombay College of Pharmacy, Kalina, Mumbai, India.
authors.forename: M S
authors.initials: MS
authors.lastname: Nagarsenker
authors.forename: V Y
authors.initials: VY
authors.lastname: Londhe
authors.forename: G D
authors.initials: GD
authors.lastname: Nadkarni
mesh_terms: D000818:Animals; D019540:Area Under Curve; D001682:Biological Availability; D002626:Chemistry, Pharmaceutical; D004339:Drug Compounding; D016503:Drug Delivery Systems; D005069:Evaluation Studies as Topic; D005123:Eye / Q000378:metabolism*; D008081:Liposomes / Q000008:administration & dosage* / Q000737:chemistry; D008297:Male; D008657:Metabolic Clearance Rate; D010316:Particle Size; D011680:Pupil / Q000187:drug effects; D011817:Rabbits; D013696:Temperature; D013997:Time Factors; D014331:Tropicamide / Q000737:chemistry / Q000493:pharmacokinetics*
chemical_list: D008081:Liposomes; D014331:Tropicamide