Abstract
Purpose:
Ciprofloxacin (CIP) is a synthetic fluoroquinolone anti-bacterial agent usually prescribed for the treatment of corneal keratitis, conjunctivitis and other bacterial infections of the eye. The goal of the present project is to fabricate CIP loaded nanostructured lipid carriers (NLCs), to investigate their potential and feasibility in terms of topical ocular delivery and disposition, and to compare them with PEGylated CIP-NLCs.
Methods:
CIP-NLCs were prepared by hot homogenization method comprising solid lipid (Glyceryl monostearate (GMS) and 1,2-distearoyl-sn-glycero phosphoethanolamine, sodium salt (DSPE) and liquid lipids (oleic acid). N-(Carbonyl-methoxypolyethylene glycol-2000)-DSPE was used, in combination with GMS, to prepare PEGylated CIP-NLCs. Total amount of lipid employed in the NLCs was 6% w/v of which solid lipid constituted 50% and oleic acid made up the remaining 50%. Drug load in the formulations was maintained at 0.3% w/v. Formulations prepared were then characterized and evaluated with respect to in vivo ocular tissue distribution 2 h post topical administration in a conscious rabbit model. All animal studies conformed to the tenets of the ARVO statement on the use of animals in ophthalmic vision and research and the University of Mississippi IACUC approved protocols.
Results:
CIP content in the formulations were within 95-98% of the theoretical value. Mean hydrodynamic radius, zeta potential, polydispersity index & entrapment efficiency of the CIP-NLCs and PEGylated CIP-NLCs were 154, 55.3 nm; 0.072, 0.5 mV; 0.21, 0.29; and 72.5, 83.66 %, respectively. CIP levels in the cornea attained with the CIP-NLCs and PEGylated CIP-NLCs were 1.91 ± 0.47, 3.73 ± 1.23 µg/g of tissue, respectively. Drug levels obtained in all ocular tissues was nearly 2-3 fold higher with the PEGylated CIP-NLCs.
Conclusions:
Results suggest that surface functionalization of NLCs with PEGylated chains could further improve intraocular penetration and retention of the drug molecules and thus enhancing the ocular bioavailability and distribution.