Bicontinuous sucrose ester microemulsion: a new vehicle for topical delivery of niflumic acid

The bicontinuous sucrose ester based microemulsion microstructure was characterised by a freeze fracture electron micrograph (FFEM) technique. The relationship between the microstructure and the efficacy of the microemulsion (ME) as a drug carrier system was investigated. The bioavailability of niflumic acid, a potent anti-inflammatory drug, incorporated at different concentrations in the microemulsion vehicle was investigated in vivo and compared with Nifluril® ointment (3%), a commercially available form. The methyl nicotinate model was used to induce inflammation. Following topical application of methyl nicotinate, various niflumic acid forms were immediately applied to the skin. The vascular response to methyl nicotinate on the treated areas was monitored by a Laser Doppler Flowmetry technique. The results exhibit the performance of the microemulsion vehicle as a niflumic acid carrier compared to the marketed form. The 1% niflumic acid microemulsion is as efficient as the 3% niflumic acid ointment.