Thesis (Ph.D.) - Cairo University - Faculty of Pharmacy - Department of Pharmaceutics

Cataract is an opacification of all or specific regions of the lens that results in obstruction of light and gradual loss of vision. It continues to be the leading cause of blindness worldwide, accounting for over 50% of the world{u2019}s blind population.The underlying causes of cataract are quite diverse with the majority of cataracts acquired after middle age. Congenital or juvenile cataracts, considered as early onset cataracts, are less common but nonetheless have significant visual consequences.L-Carnosine (b-alanyl-L-histidine) is generally found in milli-Mole (mM) concentrations in several mammalian tissues, potentially exhibiting different metabolic activities. The previously published data suggest that L-carnosine has excellent potential to act as a natural antioxidant with hydroxyl radical, singlet oxygen scavenging and lipid peroxidase activities. A striking effect of L-carnosine is its demonstrated ability to prevent, or partially reverse, lens cataract. The N-acetyl derivative of carnosine (NAC) of carnosine exists in the cardiac and skeletal mammalian muscles and the total concentration of these imidazoles may lie within the measured range of L-carnosine in skeletal muscle.The advantage of NAC to act as an in vivo universal antioxidant with physiological and therapeutic relevance deals with its ability to give efficient protection against oxidative stress in the lipid phase of biological membranes and in aqueous environment due to turnover into L-carnosine. Due to its relative hydrophobicity compared with L-carnosine, NAC might penetrate through the cornea gradually, thus maintaining longer the active therapeutic concentration of L-carnosine in aqueous humor of the treated eye

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