Glaucoma is extensively treated with topical eye drops containing drugs. However, the retention time of the loaded drugs and the in vivo bioavailability of the drugs are highly influenced before reaching the targeted area sufficiently, due to physiological and anatomical barriers of the eye, such as rapid nasolacrimal drainage. Poor intraocular penetration and frequent administration may also cause ocular cytotoxicity. A novel approach to overcome these drawbacks is the use of injectable hydrogels administered intravitreously for sustained drug delivery to the target site. These injectable hydrogels are used as nanocarriers to intimately interact with specific diseased ocular tissues to increase the therapeutic efficacy and drug bioavailability of the anti-glaucomic drugs. The human eye is very delicate, and is sensitive to contact with any foreign body material. However, natural biopolymers are non-reactive, biocompatible, biodegradable, and lack immunogenic and inflammatory responses to the host whenever they are incorporated in drug delivery systems. These favorable biomaterial properties have made them widely applicable in biomedical applications, with minimal adversity. This review highlights the importance of using natural biopolymer-based intravitreal hydrogel drug delivery systems for glaucoma treatment over conventional methods.

Background Hydrogel is a structure with three-dimension that have the potential to absorb and retain water inside of it. Currently hydrogels made from natural biopolymers are preferred in the discipline of biomedicine due to their nature of blood compatibility, adhesion of platelets and protein binding, ease of administration and delivery of ingredients to the place of action. The purpose of this study is preparing blood compatible injectable hydrogels from naturally obtained polymers of biomaterials in a combination of different proportion, characterizing and analyzing its physiochemical blood compatibility and morphological structures. Methods Three different compositions of gelatin, dialyzed SF, curcumin and N, N methylene bisacrylamide (MBA) in different groups coded by IVA, IVB and IVC were used. The combinations were evenly mixed on a magnetic stirrer. After an hour of the gelation process it has been kept under refrigerator at 4°C. For characterization and biocompatibility studies of hydrogel swelling test and biodegradation analysis, SEM, FTIR, In-vitro coagulation tests, total serum albumin and cholesterol level analysis were applied, Results Injectable hydrogel successfully made from the combinations of SF/GE/CU/ in the presence of a cross linker MBA and the result from physiochemical biocompatibility and morphological characteristics study were confirmed that natural biopolymers used in this study are a candidate for biomedical applications. Conclusion The result confirmed that the composition coded by IVC was identified the most stable composition and suitable in its morphological structure with excellent blood compatible nature recommended for further biomedical applications.