Viscosity-increasing agents carbomers

Semi-solid gel type preparations have also been developed for ophthalmic delivery as an alternative to traditional ointments, based on the effect of increasing the viscosity to prolong the retention of drug in the eye (for example, Pilopine HS gel, Alcon Laboratories, Inc.). Several types of gelling agents have been used, such as polyacrylic acid derivatives, carbomer and hypromellose. 

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