<i>In vitro</i> , <i>ex vivo</i> , and <i>in vivo</i> evaluation of polysaccharide based thermo-sensitive <i>in situ</i> gel for the treatment of glaucoma

One of the disadvantages of traditional ophthalmic formulations is their short residence time in the eye. An <i>in situ</i> gel is recommended as a remedy, as it can be converted into a gel upon contact with the eye and adhere for an extended period. Tamarind seed polysaccharide (TSP) is non thermo-sensitive and possesses the necessary properties to be used as a vehicle for administering medication to the eye. However, the administration of medication into the eyes through TSP based <i>in situ</i> gel has not yet been studied. <i>N</i>-isopropyl acrylamide was grafted onto TSP to make it temperature sensitive. Then, a TSP-based thermo-sensitive <i>in situ</i> gel-forming solution loaded with dorzolamide hydrochloride (2% w/v) was developed and evaluated through <i>in vitro</i>, <i>ex vivo</i>, and <i>in vivo</i> tests. The <i>in situ gel</i> forming solution turns into a gel at 37°C. The safety and efficacy of the formulation were confirmed through an <i>in vivo</i> study on rabbit eyes with induced glaucoma. The findings indicate that the <i>in situ</i> gel significantly reduced intraocular pressure (IOP), with effects comparable to those of marketed eye drops.