Multicomposite ultrathin capsules for sustained ocular delivery of ciprofloxacin hydrochloride

The present work is intended to develop a sustained bioadhesive drug delivery system for delivery of Ciprofloxacin Hydrochloride in Cul-de-Sac for sustained and effective antimicrobial chemotherapy. For this, ultrathin multicomposite capsular systems were selected.

Multicomposite ultrathin capsules are molecular assemblies of tailored architecture having layer-by-layer adsorption of oppositely charged macromolecules onto colloidal particles. In the present study colloidal calcium phosphate core and gluateraldehyde fixed RBCs were used as core on which alginate (-vely charged) and polyallylamine hydrochloride (+vely charged) polyelectrolyte coating was deposited alternatively upto 10th layer. The coating in each subsequent layer was determined by changes in zeta potential. Ciprofloxacin hydrochloride was loaded in the capsules by incubation with the capsules suspended in phosphate buffer saline pH 7.4. The cores of the capsules were then removed by treatment with 0.1N HCl for calcium phosphate core and by sodium hypochlorite for RBC cored capsules. The hollow ciprofloxacin HCl loaded capsules were the evaluated in-vitro for pattern of layer-by-layer drug loading, drug release, stability at various temperatures and ionic concentrations and corneal retention.

The core removal process was found to have minimal effects on drug loading in capsules. The drug loading was found to be higher for RBC cored hollow capsules and hence release rate was lower as compared to calcium cored hollow capsules. Draize test for corneal irritancy proved that the capsules were not irritating. The capsules were found to deliver the ciprofloxacin in cul-de-sac of rabbit's eyes for prolonged period.

Based on corneal retention studies and tear drug concentration, the capsules can be considered for suitable and safe use for sustained ocular delivery of drugs.