Minimally invasive dissolving microneedles for ocular brinzolamide delivery / 药学学报

ABSTRACT

The permeation and pharmacodynamics of ocular drugs are influenced by the corneal barrier. Here, a hard-soluble drug, brinzolamide, was selected as the model drug and used for preparation of minimally invasive dissolving microneedles. Brinzolamide was dissolved in ethanol and polyvinylpyrrolidone (PVP) K90 was added and dissolved. The mixture solution was casted into the dissolving microneedles mold and dried and brinzolamide dissolving microneedles (BMN) were obtained after demolding. The stereoscopic and scanning electron microscopic images showed that BMN were conical needles with the height of 750 μm, the bottom diameter of 300 μm, and the inter-tip distance of 500 μm. The dissolving microneedles patch was composed of 10×10 arrays with the area of 1 cm2 and the high drug load of 7.3 mg·cm-2. BMN showed a rapid in vitro drug release with 93% accumulative release at 2 h and the high drug corneal permeation amount of 877 ± 105 μg. BMN exhibited the high mechanical strength of 0.32 N/needle, leading to easy rat corneal insertion with the depth of 200 μm. Moreover, BMN were rapidly dissolved in the cornea, and more importantly, the damaged cornea were quickly self-healed within 24 h. Animal experiments were approved by the Ethics Committee of Beijing Institute of Radiation Medicine, Academy of Military Medical and the experiments were conducted in accordance with relevant guidelines and regulations. Ocular minimally invasive dissolving microneedles have the advantages of corneal minimal wounds and rapid healing, high drug loading, and high permeability, favoring the treatment of ocular diseases.