CONTRIBUTIONS ON FORMULATION AND PRELIMINARY EVALUATION OF OCULAR COLLOIDAL SYSTEMS OF CHITOSAN AND POLOXAMER 407 WITH BUPIVACAINE HYDROCHLORIDE
TEODORA IRIMIA, GABRIELA CORNELIA MUŞAT *, RĂZVAN MIHAI PRISADA, MIHAELA VIOLETA GHICA, CRISTINA ELENA DINU-PÎRVU, VALENTINA ANUŢA, BRUNO ŞTEFAN VELESCU, LĂCRĂMIOARA POPA
“Carol Davila” University of Medicine and Pharmacy Bucharest, 37, Dionisie Lupu Street, 020021, Bucharest, Romania
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The aim of this paper was the formulation and preliminary evaluation of colloidal systems with improved mechanical and
mucoadhesive properties in order to increase ocular retention time and drug bioavailability. Polymeric mixtures of chitosan
(0.3%), a pH-sensitive polymer, and poloxamer 407 (12%, 15%, 18%), thermoresponsive polymer, with bupivacaine
hydrochloride (0.25%) were prepared. Gelling temperature, wettability, rheological behaviour and in vitro drug release were
evaluated. The formulation containing 15% poloxamer 407 is converted to a colloidal dispersion at 35°C, the temperature of
the ocular surface. Contact angle values of colloidal systems at physiological temperature (35°C) were lower than those
corresponding to formulations at non-physiological temperature (25°C), indicating a higher spreadability over the ocular
surface. Rheological studies have shown pseudoplastic behaviour and the poloxamer concentration increased the viscosity of
the formulations. In vitro bupivacaine hydrochloride delivery from colloidal systems revealed that drug release mechanism
followed Higuchi model. The colloidal dispersions with chitosan and poloxamer 407 could be viable alternatives to increase
the bioavailability of bupivacaine hydrochloride in topical ocular anaesthesia.
