Liquid crystalline microspheres for 5-fluorouracil specific release

The aim of this study was the synthesis and characterization of swellable microspheres based on fenoprofen and poloxamer. Morphology, average diameter and thermal behaviour of obtained microparticles were studied by scanning electron microscopy, dynamic light scattering, and differential scanning calorimetry. The swelling degree was evaluated at different time intervals and at two pH values. The results revealed that the microspheres swelled better at a pH 6.2, typical of tumour pathologies, than at 7.4, physiological one. Then, microspheres were impregnated with 5-fluorouracil with the aim to increase its bioavailability and reduce its toxicity. The percentage of cumulative amount of 5-fluorouracil released from microparticles was calculated at pH 6.2. Surprisingly, calorimetry and optical microscopy showed the preservation of fenoprofen liquid crystallinity in the obtained microparticles with a transition temperature close to those of typical tumour-sites. The liquid crystallinity of microparticles could be exploited to modulate the release of 5-fluorouracil to tumour site.

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