Development and in vitro/in vivo evaluation of thermo-sensitive in situ gelling systems for ocular allergy

Abstract

Ocular allergy is one of the most common disorders of the eye surface. Following diagnosis this condition is typically treated with preparations containing antihistamines. However, anatomy of the eye and its natural protective mechanisms create challenges for ocular drug delivery. Rapid elimination of antihistamine substances due to short residency times following application can lead to insufficient treatment of ocular allergies. With this in mind, the aim of this study was to prepare a controlled ocular delivery system to extend the retention time of olopatadine hydrochloride (OLO) and in doing so to reduce the need for frequent application. We developed extended-release ocular in situ gelling systems for which in vivo retention times were determined in sheep following in vitro characterization and cytotoxicity studies. In vivo results were then compared to commercially available Patanol eye drops. the transparent gels formulated using appropriate amounts of polymers and having longer ocular retention times appear to be a viable alternative to commercially available eye drops.

In vitro–in vivo evaluation of tetrahydrozoline‐loaded ocular in situ gels on rabbits for allergic conjunctivitis management

“…From this fact, it can also be assumed that the in situ gels will not present irritancy and immediate production of tear fluid (Üstündaǧ‐Okur et al, 2014). Similarly, Güven et al demonstrated that ocular in situ gels based on poloxamers and loaded with olopatadine showed that the pH of the formulations was between 6.5 and 7 (Güven et al, 2019). In our previous study, which the in situ gels incorporated voriconazole, the pH results were also in the same limits (Üstündağ Okur et al, 2019).…”

“…Besides, there are also other methods as the hot process which, however, leads to undesirable physiochemical effects as the formation of polymeric lumps (Swain, Patel, Gandhi, & Shah, 2019). There are various polymers which are used for the preparation of the in situ gels, either natural or synthetic (Güven, Berkman, Şenel, & Yazan, 2019; Üstündağ Okur et al, 2019). Poloxamers are triblock thermoresponsive copolymers frequently applied in pharmaceutical technology and ocular delivery.…”

Natural Ergot Alkaloids in Ocular Pharmacotherapy: Known Molecules for Novel Nanoparticle-Based Delivery Systems

“…When considering ocular drug delivery, there is a substantial number of issues related to the precorneal area of the eye that can have major impact on the drug’s bioavailability in the expected target issues. Since both lacrimation and blinking profoundly influence the residence time of liquid ocular drug delivery systems, their comfort on the eye seems essential [ 46 , 47 ]. Placing the drug delivery system as deeply as possible into the lower cul-de-sac will assist in patient comfort, as well as increase the residence time.…”

“…Polymeric nanoparticles dispersed in a thermosensitive gel were reported to be superior to commercial eye drops [ 46 ]. Olopatadine hydrochloride, a histamine H 1 receptor antagonist with an effect on human conjunctival mast cells used in eye allergies, was loaded into in situ gel polymeric formulations to reduce the need for frequent application.…”

Preparation and detailed characterization of fusidic acid loaded in situ gel formulations for ophthalmic application

“…Similarly, Patel et al [26] prepared in situ ocular gel formulations containing hydroxyl propyl methyl cellulose and PLX 407 and found pH values between 6.8 and 7.4. Guven et al [27]prepared ocular extendedrelease in situ gels against ocular allergy and the pH value of these formulations was found between 6.50 and 7.00, which was suitable for ocular use.…”