Abstract
Blindness and impaired vision are considered as the most troublesome health conditions leading
to significant socioeconomic strains. The current study focuses on development of
nanoparticulate systems (i.e., niosomes) as drug vehicles to enhance the ocular availability of
betaxolol hydrochloride for management of glaucoma. Betaxolol-loaded niosomes were further
laden into pH-responsive in situ forming gels to further extend precorneal retention of the drug.
The niosomes were evaluated in terms of vesicle size, morphology, size distribution, surface
charge and encapsulation efficiency. The optimized niosomes, comprised of Span® 40 and
cholesterol at a molar ratio of 4:1, displayed particle size of 332 ± 7 nm, zeta potential of -46 ± 1
mV, and encapsulation efficiency of 69 ± 5%. The optimal nanodispersion was then incorporated
into a pH-triggered in situ forming gel comprised of Carbopol® 934P and hydroxyethyl cellulose.
The formed gels were translucent, pseudoplastic, mucoadhesive, and displayed a sustained in
vitro drug release pattern. Upon instillation of the betaxolol‐loaded niosomal gel into rabbits’
eyes, a prolonged intraocular pressure reduction and significant enhancement in the relative
bioavailability of betaxolol (280 and 254.7%) in normal and glaucomatous rabbits, were attained
compared to the marketed eye drops, respectively. Hence, the developed pH-triggered
nanoparticulate gelling system might provide a promising carrier for ophthalmic drug delivery
and for improved augmentation of glaucoma.