Abstract
Acetazolamide (ACZ) is a diuretic used in glaucoma treatment; it has many side effects. Carvedilol (CAR) is a non-cardioselective beta-blocker used in the treatment of elevated intraocular pressure; it is subjected to the first-pass metabolism and causes fluids accumulation leading to edema. This study focuses on overcoming previous side effects by using a topical formula of a combination of the two previous drugs. Sixty formulations of niosomes containing Span 20, Span 60, Tween 20, and Tween 60 with two different ratios were prepared and characterized. Formulation with the lowest particle size (416.30 ± 0.23), the highest zeta potential (72.04 ± 0.43 mv), and the highest apparent coefficient of corneal permeability (0.02 ± 0.29 cm/h) were selected. The selected formula was incorporated into the gel using factorial design 23. Niosomes (acetazolamide/carvedilol) consisting of Span 60 and cholesterol in the molar ratio (7:6), HMPC, and carbopol with two different ratios were used. The selected formula was subjected to an in vivo study of intraocular pressure in ocular hypertensive rabbits for 60 h. The sustained gel formula of the combination decreased (IOP) to normal after 1 h and sustained efficacy for 4 days. Histological analysis of rabbit eyeballs treated with the selected formula showed improvement in glaucomatous eye retinal atrophy.
Highlights
Glaucoma is a category of eye disease that may lead to vision loss caused by damage to the optic nerve and permanent blindness
All formulation prepared by using cholesterol was used with surfactants as an enhancer of niosomal membrane rigidity, as enhancer ability to cement the leaking space in the bilayer membranes to increase potency and efficacy of combination drug niosomes and their gel
Compared to shorter alkyl chain surfactants, higher trapping efficiency is obtained with longer alkyl chain surfactants, niosomes obtained with Span 60 (C16) have a greater EE percentage than those obtained with Span 20 (C12) since Span 60 has the longest alkyl chain among them [35]
Summary
Glaucoma is a category of eye disease that may lead to vision loss caused by damage to the optic nerve and permanent blindness. Several distinct benefits are provided by transdermal delivery systems They avoid factors such as pH, enzymatic activity, and drug–food interactions that affect drug gastrointestinal absorption and pass the first-pass effect, providing continuous-release delivery for several days (useful for short-lived drugs with an elimination half-life) [15]. Targeted drug delivery is directly to the eye where the therapeutic effect is needed and there is ease of administration, since it can be administered in liquid form, much like eye drops and topical eye gel solutions The advantage of this technique drug used with low concentration due to having high permeability can penetrate ocular by transcellular or paracellular or a combination of them [17]. The current research focuses on investigating the topical efficacy of ACZ alone, CAR alone, and a mixture of ACZ and CAR for the treatment of glaucoma
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