Chitosan-Based In Situ Gels for Ocular Delivery of Therapeutics: A State-of-the-Art Review

• Published in: Marine drugs Vol. 16; no. 10; p. 373
• Main Authors: Irimia, Teodora, Dinu-Pîrvu, Cristina-Elena, Ghica, Mihaela Violeta, Lupuleasa, Dumitru, Muntean, Daniela-Lucia, Udeanu, Denisa Ioana, Popa, Lăcrămioara
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 09.10.2018; MDPI
• Subjects: Acids; Animals; Biocompatibility; Biodegradability; Biodegradation; Chemistry, Pharmaceutical - methods; Chitosan; Chitosan - administration & dosage; Chitosan - chemistry; Cornea; Cornea - drug effects; Drug delivery systems; Drug Delivery Systems - methods; Drugs; Evaluation; Formulations; Fungicides; Gelation; Gels; Gels - administration & dosage; Gels - chemistry; Humans; Hydrogels; Hydrogen bonds; in situ gels; Mechanical properties; Medicine; mucoadhesion; ocular delivery; Ointments; Ophthalmic Solutions - administration & dosage; Ophthalmic Solutions - chemistry; Ophthalmology; pH effects; Pharmaceutical sciences; Pharmacy; Phase transitions; Physiology; Polymers; Polymers - chemistry; Reproducibility; Reproducibility of Results; Review; Solutions; sol–gel transition; State-of-the-art reviews; Stimuli; Wound healing; Romania; chitosan; sol–gel transition; ocular delivery; mucoadhesion; in situ gels
• ISSN: 1660-3397; 1660-3397
• DOI: 10.3390/md16100373

Ocular in situ gels are a promising alternative to overcome drawbacks of conventional eye drops because they associate the advantages of solutions such as accuracy and reproducibility of dosing, or ease of administration with prolonged contact time of ointments. Chitosan is a natural polymer suitable for use in ophthalmic formulations due to its biocompatibility, biodegradability, mucoadhesive character, antibacterial and antifungal properties, permeation enhancement and corneal wound healing effects. The combination of chitosan, pH-sensitive polymer, with other stimuli-responsive polymers leads to increased mechanical strength of formulations and an improved therapeutic effect due to prolonged ocular contact time. This review describes in situ gelling systems resulting from the association of chitosan with various stimuli-responsive polymers with emphasis on the mechanism of gel formation and application in ophthalmology. It also comprises the main techniques for evaluation of chitosan in situ gels, along with requirements of safety and ocular tolerability.