Development of galangal essential oil-based microemulsion gel for transdermal delivery of flurbiprofen: simultaneous permeability evaluation of flurbiprofen and 1,8-cineole Jie Dong Xue-min Zhu Feng-ye Wu Bing-qing Yang Han Feng Yun-fei Dong Wei Gu Jun Chen 10.6084/m9.figshare.11466957.v2 https://tandf.figshare.com/articles/journal_contribution/Development_of_galangal_essential_oil-based_microemulsion_gel_for_transdermal_delivery_of_flurbiprofen_Simultaneous_permeability_evaluation_of_flurbiprofen_and_1_8-cineole/11466957 <p>Flurbiprofen (FP) is one of the most potent nonsteroidal anti-inflammatory drugs with very low bioavailability of approximately 12% following transdermal administration, compared to that after oral administration. This study aimed to deliver FP as a microemulsion (ME) gel by transdermal administration. Galangal essential oil (GEO) was extracted from <i>Rhizoma Alpiniae Officinarum</i> and identified by GC-MS. The most abundant constituent was determined to be 1,8-cineole (52.06%). Compared to azone, GEO was proved to exert significantly higher (<i>p</i> < .01) penetration enhancement effect and significantly (<i>p</i> < .001) lower skin cell toxicity. The formulation (FP-GEO-ME gel) was prepared using GEO as an oil phase and a penetration enhancer. Compared to that of FP solution, the enhancement ratio (ER) of FP-GEO-ME gel was 4.06. In addition, more than 25% 1,8-cineole permeated through the rat skin. <i>In vivo</i> pharmacokinetic studies revealed that the AUC<sub>0–t</sub> of FP after transdermal administration of FP-GEO-ME gel was higher by approximately 4.56-fold than that of marketed FP cataplasms. The relative bioavailability of FP and 1,8-cineole after transdermal administration compared to oral administration of FP-GEO-ME were determined to be 96.58% and 85.49%, respectively. FP-GEO-ME gel significantly inhibited carrageenan-induced hind-paw edema and decreased PGE2 levels in rat serum. GEO-ME gel also exhibited significant anti-inflammatory effects at 2 h after the therapy (<i>p</i> < .05). The synergistic effects of FP and GEO were expected for the application of FP-GEO-ME gel. In conclusion, GEO-ME gel may be a promising formulation for transdermal administration of anti-inflammatory hydrophobic drugs, such as FP.</p> 2020-01-08 21:37:00 flurbiprofen microemulsion gel pharmacokinetics anti-inflammatory effect transdermal 1,8-cineole galangal essential oil