Anti-angiogenic biomolecules in neovascular age-related macular degeneration; therapeutics and drug delivery systems.

Blindness in the elderly is often caused by age-related macular degeneration (AMD). The advanced type of AMD known as neovascular AMD (nAMD) has been linked to being the predominant cause of visual impairment in these people. Multiple neovascular structures including choroidal neovascular (CNV) membranes, fluid exudation, hemorrhages, and subretinal fibrosis, are diagnostic of nAMD. These pathological alterations ultimately lead to anatomical and visual loss. It is known that vascular endothelial growth factor (VEGF), a type of proangiogenic factor, mediates the pathological process underlying nAMD. Therefore, various therapies have evolved to directly target the disease. In this review article, an attempt has been made to discuss general explanations about this disease, all common treatment methods based on anti-VEGF drugs, and the use of drug delivery systems in the treatment of AMD. Initially, the pathophysiology, angiogenesis, and different types of AMD were described. Then we described current treatments and future treatment prospects for AMD and outlined the advantages and disadvantages of each. In this context, we first examined the types of therapeutic biomolecules and anti-VEGF drugs that are used in the treatment of AMD. These biomolecules include aptamers, monoclonal antibodies, small interfering RNAs, microRNAs, peptides, fusion proteins, nanobodies, and other therapeutic biomolecules. Finally, we described drug delivery systems based on liposomes, nanomicelles, nanoemulsions, nanoparticles, cyclodextrin, dendrimers, and composite vehicles that are used in AMD therapy.

Thiolated chitosan-lauric acid as a new chitosan derivative: Synthesis, characterization and cytotoxicity.

Chitosan as a biopolymer is an attractive vehicle for biomedical applications due to its unique characteristics. In order to improve chitosan's physicochemical features, chemical modification has been carried out to make it more suitable for such approaches. The aim of this study was to prepare and evaluate thiolated chitosan-lauric acid as a new chitosan derivative for biomedical use. Lauric acid was introduced to chitosan via stable amide bond between carboxylic acid group of fatty acid and the amine in the chitosan and thiolation was carried out using thioglycolic acid. Resulted polymers were characterized by FTIR, 1H NMR and TGA. Moreover, cell viability assessment of new derivative was performed using MTT method. FTIR and 1H NMR results showed that both substitution reactions were successfully completed. Furthermore, new synthesized polymer had no significant cytotoxicity against normal gingiva human cells (HGF1-PI 1).These findings confirm that this new derivative can be introduced as a suitable polymer for biomedical purposes such as mucosal drug delivery.