Poor bioavailability and therapeutic response of conventional therapy due to many pre-corneal constraints necessitate
the development of novel controlled and sustained ocular drug delivery to become a standard one in modern
pharmaceutical era. This investigation aimed to study the drug release kinetics of betaxolol hydrochloride from a hydrophobic
matrix system of PMMA cast with incorporating different proportions of polyethylene oxide (PEO) and evaluate
its ability to improve ocular bioavailability and duration of action for the drug. Matrix type ocular inserts were prepared
by the film casting technique and characterized in vitro by drug release studies using a flow through apparatus that simulated
the eye conditions. All the formulations were subjected to physicochemical evaluation. Rabbit model with steroid
induced glaucoma was used to establish in vivo efficacy of inserts. Polymer composition and concentration significantly
affected the drug release based on change in diffusional path length and formation of gelaneous pores by polymer erosion.
Formulations released the drug by non-fickian diffusion including anomalous transport (0.5<n<1) and super case II transport
(n>1). It was also observed that increasing the proportion of PEO in to PMMA does not affect the blend miscibility.
IVIVC suggested no significant difference (P< 0.001) between in vitro and in vivo release of drug from inserts. In vivo
IOP lowering activity was better for optimized insert F8 (for 24 h) as compared to eye drops (10 h). This ocular insert
could be a promising once-a-day sustained release formulation for treating glaucoma.
Keywords: Betaxolol hydrochloride, ocular delivery, once-a-day ocuserts, polymer composite, release kinetics, sustained
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