Ocular delivery

The present study attempted to evaluate acyclovir loaded PLGA nanoemulsions for ocular delivery. The acyclovir loaded PLGA nanoemulsions were prepared by spontaneous emulsification method. Five batches were prepared and labeled as NE-1, NE-2, NE-3, NE-4 and NE-5 by changing the concentration of PLGA polymer. The prepared nanoemulsions were subjected for its physico-chemical characterization, in-vitro diffusion, release kinetics and stability studies. FT-IR and DSC shown the drug and polymer were compatible with each other and no change in their chemical nature. The morphology of nanoemulsion shows spherical in shape with smooth surfaces. The particle size and zeta potential and Poly dispersity index were determined by malvern instrument and the results shown that the prepared nanoemulsion has significant ranges of particle size (164.67 - 244.43nm), zeta potential (-33.20 to -37.60) and poly dispersity index (0.256-0.499). Drug entrapment efficiency and % practical yield ranges between (54.97-79.67) and (46.83-58.01) respectively. The in-vitro % drug release of acyclovir indicates formulation NE-4 has significant sustained release compared with other formulations. The release kinetic data of all formulations are fitted with Higuchi’s model and non-fickian diffusion mechanism. The stability study indicates 5°C±3°C and 25°C±2°C/60%±5% RH is ideal storage condition for nanoemulsion for longer period. Thus it can be conclusively stated that the acyclovir loaded PLGA nanoemulsions may be considered as an improved ophthalmic drug delivery system for the treatment of ocular viral infections.

The objectives of this study were to maximize; a) the in vitro transcorneal release, b) the IOP-lowering effect and, c) the duration of action, of Latanoprost acid (LAT) ophthalmic gels. The in vitro transcorneal release of LAT from a 1st set of gel formulations that containing different concentrations of Azone™ (as enhancer) with fixed concentration of C-974® (as mucoadhesive) were studied. Formulation that showed greatest permeability parameters at lowest Azone™ concentration was selected for preparation of a 2nd set of ocular gels containing various C-974® concentrations. The in vitro transcorneal release was assessed, and the best C-974® concentration required for preparation of formulations that can be conceded as ideal ophthalmic LAT gels hve been pinpointed and scaled up for in vivo IOP-lowering efficacy study using TONO-PEN™ AVIA tonometer in rabbits for 4-consecutive days.  Various test formulations have showed significant but varied augmentations in both, in vitro and in vivo results. Formulations (GAZ-4) & GC-4 have shown the highest therapeutic IOP lowering effects; i.e., (7.8±1.8), (6.5±2.1), respectively. Particularly noteworthy with both formulations the IOP base-line didn’t re-established after 24 hours, and their durations of action in the single-dose study were 47±2.25, and 48±1.5, respectively. The in vitro release, onset, magnitude & duration of action of action of LAT gels have been enhanced and extended for up to 2-day with two gel formulations.  Nonetheless, the success in developing a novel ophthalmic formulation depended for great extent upon the crucial net outcomes of a very sensitive interplay/balance between the drug and additives.