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.

The objective of this review is to compile updated scientific information on the conventional and novel approaches to the ocular delivery of medication. Owing to the special features and requirements of a specific site delivery system, there is a need for the refinement of novel drug delivery systems. The conventional ocular dosage forms often possess problems like quick pre-corneal drug excretion because of its nasolacrimal drainage which may lead to tearing turnover and finally result in low ocular bioavailability. The design of novel delivery systems helps in delivering the therapeutic agent very efficiently into the desired areas of the eyes by their unique particle size and also because of their biocompatibility with ocular tissues. In addition, they also offer good contact time, improved drug loading, and releasing properties with less drug loss and low toxicity. All these advantages of a novel delivery system directly cause an improvement in the patient’s satisfaction and the bioavailability of the therapeutic agent. In this review article, information about the different ocular novel drug delivery systems such as nanoparticles, liposomes, niosomes, microneedles, and dendrimers is summarized and discussed. Noteworthy contributions by various researchers in the field of these delivery systems have been also been mentioned. Therefore, this article will be beneficial for future researchers and formulation developers working on the design and development of ocular therapeutic delivery systems.