Development of brimonidine niosomes laden contact lenses for extended release and promising delivery system in glaucoma treatment

Background

Increased intraocular pressure is a common symptom of glaucoma. In severe circumstances, it may result in loss of eyesight. Glaucoma treatment is difficult due to ocular physiological barriers that prevent medications from reaching the afflicted area. Traditional formulations (eye drops) have a short residence period and are rapidly drained away via the nasolacrimal duct, resulting in increased adverse drug responses and lower efficacy. The usage of nanoparticles such as niosomes could be one potential answer to these problems. While niosomes improve drug penetration, they have little effect on ocular retention of the medication. Contact lenses containing niosomes can assist to overcome this disadvantage.

Objective

This study aims to prepare and evaluate Brimonidine niosomes laden contact lenses for the treatment of Glaucoma.

Methods

Brimonidine niosomes were prepared using thin film hydration method and evaluated. The contact lenses were soaked in the niosomal formulation at varying intervals (3–10 days). Thereafter, the contact lenses were evaluated for %transmittance, %swelling index, drug quantification and in vitro drug release. The pharmacodynamic studies were conducted to assess the reduction in intraocular pressure (IOP) in albino rabbits. The research compared the results of the reduction in intraocular pressure caused by Brimonidine niosomes laden contact lenses with a marketed preparation of niosomes.

Results

Higher concentration of the drug was loaded in contact lenses loaded with Brimonidine niosomes compared to the marketed formulation, by soaking method. The contact lenses exhibited an optimal %transmittance of 98.02 ± 0.36 and %swelling index of 50.35 ± 0.57. Increase in the soaking time up to 7 days led to an increase in the drug concentration in the contact lenses. However, no further increase was observed after the 7th day due to saturation of the contact lenses. Brimonidine niosomes laden contact lenses provided a reduction in intraocular pressure that was similar to the marketed preparation. Further, the contact lenses provided extended release up to 20 h.

Conclusion

Brimonidine niosomes laden contact lenses exhibited superior drug loading through the soaking method, displaying optimal %transmittance and %swelling index. Soaking for 7 days increased drug concentration in contact lenses with no further increase due to saturation. These lenses reduced intraocular pressure like the marketed formulation, offering extended release for 20 h.

Graphical abstract