Rheological evaluation of poloxamer as an in situ gel for ophthalmic use

✍ Scribed by Katarina Edsman; Johan Carlfors; Roger Petersson

• Book ID: 114302713
• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 168 KB
• Volume: 6
• Category: Article
• ISSN: 0928-0987
• DOI: 10.1016/s0928-0987(97)00075-4

✦ Synopsis

The contact time of a vehicle on the cornea is of utmost importance for ocular drug delivery. In the present study rheological measurements were performed to study the gel and the sol-gel transition of an in situ gel, Poloxamer 407. The rheological measurements and a small in vivo study of ocular residence times in humans were used to evaluate poloxamer as an ocular vehicle. An increasing concentration of poloxamer resulted in a slightly increasing elasticity of the gels and a decreasing sol-gel transition temperature. The contact time increased with increasing concentration of poloxamer which could be explained and correlated with the rheology of poloxamer solutions / gels mixed with simulated tear fluid. The maximum contact time for the preparations studied was about 1 h. The poloxamer system did not seem to be promising as an ophthalmic in situ gel due to the strong concentration dependence of the sol-gel transition temperature combined with the dilution that occurs in the eye.