RESUMEN
Eyesight is one of the most well-deserved blessings, amid all the five senses in the human body. It captures the raw signals from the outside world to create detailed visual images, granting the ability to witness and gain knowledge about the world. Eyes are exposed directly to the external environment; they are susceptible to the vicissitudes of diseases. The World Health Organization has predicted that the number of individuals affected by eye diseases will rise enormously in the next decades. However, the physical barriers of the eyes and the problems associated with conventional ocular formulations are significant challenges in ophthalmic drug development. This has generated the demand for a sustained ocular drug delivery system, which serves to deliver effective drug concentration at a reduced frequency for consistent therapeutic effect and better patient treatment adherence. Recent advancement in pharmaceutical dosage design has demonstrated that a stimuli-responsive in situ gel system exhibits the favorable characteristics for providing sustained ocular drug delivery and enhanced ocular bioavailability. Stimuli-responsive in situ gels undergo a phase transition (solution-gelation) in response to the ocular environmental temperature, pH, and ions. These stimuli transform the formulation into a gel at the cul de sac to overcome the shortcomings of conventional eye drops, such as rapid nasolacrimal drainage and short contact time with the ocular surface This review highlights the recent successful research outcomes of stimuli-responsive in situ gelling systems in treating in vivo models with glaucoma and various ocular infections. Additionally, it also presents the mechanism, recent development, and safety considerations of stimuli-sensitive in situ gel as the potential sustained ocular delivery system for treating common eye disorders.
RESUMEN
The eyes are the window to the world and the key to communication, but they are vulnerable to multitudes of ailments. More serious than is thought, corneal infection by herpes simplex viruses (HSVs) is a prevalent yet silent cause of blindness in both the paediatric and adult population, especially if immunodeficient. Globally, there are 1.5 million new cases and forty thousand visual impairment cases reported yearly. The Herpetic Eye Disease Study recommends topical antiviral as the front-line therapy for HSV keratitis. Ironically, topical eye solutions undergo rapid nasolacrimal clearance, which necessitates oral drugs but there is a catch of systemic toxicity. The hurdle of antiviral penetration to reach an effective concentration is further complicated by drugs' poor permeability and complex layers of ocular barriers. In this current review, novel delivery approaches for ocular herpetic infection, including nanocarriers, prodrugs, and peptides are widely investigated, with special focus on advantages, challenges, and recent updates on in situ gelling systems of ocular HSV infections. In general congruence, the novel drug delivery systems play a vital role in prolonging the ocular drug residence time to achieve controlled release of therapeutic agents at the application site, thus allowing superior ocular bioavailability yet fewer systemic side effects. Moreover, in situ gel functions synergistically with nanocarriers, prodrugs, and peptides. The findings support that novel drug delivery systems have potential in ophthalmic drug delivery of antiviral agents, and improve patient convenience when prolonged and chronic topical ocular deliveries are intended.
RESUMEN
OBJECTIVES: Parallel comparison with 0.15% ganciclovir (GCV) ophthalmic gel to evaluate the effectiveness and safety of 0.15% GCV in situ ophthalmic gel for the treatment of herpes simplex keratitis (HSK). METHODS: This was a multicenter, randomized, investigator-masked, parallel group study. HSK patients were randomly divided into two groups, with the corresponding treatment of 0.15% GCV ophthalmic gel or 0.15% GCV in situ ophthalmic gel. Symptoms and signs were observed before administration, and 3 (±1), 7 (±1), 14 (±2), and 21 (±3) days after the administration. The clinical effective rate was considered as the primary outcome. The safety profile was evaluated by AEs, visual acuity, and ocular tolerance. RESULTS: The clinical effective rate in the per-protocol (PP) dataset for the treatment group and the control group were 95.10% and 93.00%, respectively (P = 0.5282). The noninferiority test showed significant differences (P = 0.000305, P < 0.025), indicating that the tested drug was noninferior to the control. Patients in the PP dataset of both groups experienced decreases in the total scores of clinical indicators. Ocular AEs were few but similar between the two groups. There were no significant differences between patients' visions between the two groups before and after administration in the safety analysis set. In terms of drug tolerance, the rates of patients without transient blurred vision during all the visits in the treatment group were higher than those for the control group (P < 0.05). During the third and fourth visits, the rates of patients with eye itching were 4.08% and 1.22% in the treatment group, and 13.59% and 8.14% in the control group, respectively (P < 0.05). During the second visit, the rates of patients with eye irritation were 14.42% in the treatment group and 25.71% in the control group (P < 0.05). CONCLUSION: The 0.15% GCV in situ ophthalmic gel was effective and safe for the treatment of HSK, and was not inferior to 0.15% GCV ophthalmic gel. The 0.15% GCV in situ ophthalmic gel presented superior ocular tolerance.