Investigating the ocular toxicity potential and therapeutic efficiency of in situ gel nanoemulsion formulations of brinzolamide.

Abstract

Glaucoma is an ocular disease i.e. more common in older adults with elevated intraocular pressure and a serious threat to vision if it is not controlled. Due to the limitations regarding the conventional form of brinzolamide (Azopt®), two optimum formulations of in situ gel nanoemulsion were developed. To ensure the safety and efficacy of developed formulations for ocular drug delivery, the current study was designed. MTT assay was carried out on the human retinal pigmentation epithelial cells. To investigate the irritation potential of the chosen formulations, hen's egg test-chorioallantoic membrane as a borderline test between in vivo and in vitro methods has been done. The modified Draize method was utilized to evaluate eye tolerance against the selected formulations. Intraocular pressure was measured by applying the prepared formulations to the eyes of normotensive albino rabbits in order to assess the therapeutic efficacy. Based on MTT test, cell viability for NE-2 at 0.1% and NE-1 at 0.1 and 0.5% concentrations was acceptable. The results of the hen's egg test-chorioallantoic membrane test indicated no sign of vessel injury on the chorioallantoic membrane surface for both formulations. Also, during 24h, both formulations were well-tolerated by rabbit eyes. The pharmacodynamics effects of formulations had no difference or were even higher than that of suspension in case of adding lower concentration (0.5%) of brinzolamide to the formulations. With regard to the results of the mentioned methods, our advanced formulations were effective, safe, and well-tolerated, thus can be introduced as an appropriate vehicle for ocular delivery of brinzolamide.