No abstract

Conveying the therapeutic agent to the human eye has been a struggling task for formulators and scientists because of the complicated arrangement of the eye. The therapeutic agents needed to deliver the drugs to specific sites of the eye require the crossing of various ocular barriers, which act as hitches for drug delivery. Conventional preparations present in the market do not achieve the desired therapeutic results due to their lower bioavailability, less retention time, or difficulty in reaching the site of action. In a need to overcome the challenges with these preparations, various modern technologies are being applied to address the same with outstanding results. The purpose of the present review is to focus on several innovative approaches, viz., the development of novel ocular drug delivery systems including liposomes, niosomes, nano-wafers, cubosomes, microneedles, dendrimers, and many others, adopted to combat various ocular diseases. In the present review, various novel formulations and drug delivery approaches have been taken into consideration, as developed, and reported by various scientists and researchers working in the field of ocular drug delivery systems.

Development of ceftriaxone loaded nanostructured lipid carriers to increase permeability of ceftriaxone across uninflamed meninges after parenteral administration. Lipids were selected by theoretical and experimental techniques and optimization of NLCs done by response surface methodology using Box-Behnken design. The Δδt for glyceryl monostearate and Capryol90 were 4.39 and 2.92 respectively. The drug had maximum solubility of 0.175% (w/w) in glycerol monostearate and 2.56g of Capryol90 dissolved 10mg of drug. The binary mixture consisted of glyceryl monostearate and Capryol90 in a ratio of 70:30. The optimized NLCs particle size was 130.54nm, polydispersity index 0.28, % entrapment efficiency 44.32%, zeta potential -29.05mV, and % drug loading 8.10%. In vitro permeability of ceftriaxone loaded NLCs was 5.06x10 -6 cm/s; evidently, the NLCs pervaded through uninflamed meninges, which, was further confirmed from in vivo biodistribution studies. The ratio of drug concentration between brain and plasma for ceftriaxone loaded NLCs was 0.29 and that for ceftriaxone solution was 0.02. With 44.32% entrapment of the drug in NLCs the biodistribution of ceftriaxone was enhanced 7.9 times compared with that of ceftriaxone solution. DSC and XRD studies revealed formation of imperfect crystalline NLCs. NLCs improved permeability of ceftriaxone through uninflamed meninges resulting in better management of CNS infections.