TFC045 Osmolality determination of poloxamer 407 thermosetting gels for ocular delivery

Abstract

Poloxamer 407 is a poly(oxy ethylene)–poly(oxy propylene) block nonionic copolymer frequently used in pharmaceutical preparations due to its characteristic of thermoreversible gellification; therefore, it increases the product residence time. It is used in ophthalmic formulations and because the isotonicity is desirable for an ocular delivery system, the poloxamer’s influence in the osmolality of the formulation must be evaluated. However, considering that concentrated solutions of the polymer are not easily frozen, it is difficult to analyze by freezing-point depression. Furthermore, one might suggest that as poloxamer is a large molecular weight nonionic molecule, the influence in the osmolality would be negligible. Therefore, poloxamer’s influence in this colligative property was studied by direct measurement in osmometer and by the dilution method.