Formulation and evaluation of red fruit (Pandanus conoideus) oil-based nanoemulsion loaded thermosensitive gel combined with solid microneedle for topical delivery

Red fruit (Pandanus conoideus) is a fruit that has been well-known for its ability to treat various diseases because of its abundant active ingredients. One of them is β-carotene, an antioxidant compound that could maintain the skin's health with many benefits. In this study, we developed a thermosensitive nanoemulgel formulation from red fruit extract that delivers β-carotene topically in combination with solid microneedles (SMN) to increase the bioavailability of β-carotene in the skin. The preparation of thermosensitive nanoemulgel was carried out using red fruit oil nanoemulsion and thermosensitive gel based on Pluronic® F127 and F68. The best nanoemulsion formulation droplet size was 103.43 ± 9.74 nm, with a PDI value of 0.204 ± 0.02. The characterization results showed that this thermosensitive nanoemulgel prepared has a bright reddish-orange color. Moreover, it is a liquid at room temperature and turns into a gel at body temperature to allow longer contact time with the skin. The dermatokinetic profile of the combination of red fruit oil-based thermosensitive nanoemulgel with 1 mm SMN showed a significant increase in the concentration of β-carotene up to 5-fold in skin layers for ex vivo (129.98 ± 13.39 μg/cm2) and up to 3-fold in skin layers for in vivo (51.24 ± 5.53 μg/cm2). Importantly, no hemolytic activity or irritation in vivo was found in the skin tissue, proving the primary safety of this preparation. For the first time, developing red fruit extract into a thermosensitive nanoemulgel form has provided promising approaches with safety for improving the bioavailability of β-carotene in the skin.