This study was aimed to produce a stable kenaf seed oil-nanostructured lipid carrier (KSO-NLC) sunscreen, which can help in the photoprotective effect. The nanostructured lipid carrier (NLC) formulation was optimized and selected based on the results of mean particle size, polydispersity index (PDI), and storage stability of formulas at both chilled (4 AE 2 C) and room (25 AE 2 C) temperatures. Uvinul A plus B was added to KSO-NLC with the optimized formula (80% w/w aqueous phase, 20% w/w lipid phase, and 7% w/w of surfactants with a ratio of 70:15:15 of Tween 20: poloxamer 188: lecithin). The mean particle size distribution (224.73 AE 1.56 nm) and PDI (0.41 AE 0.01) of KSO-NLC were determined and were found to be stable against storage without creaming or phase separation. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging and 2,2 0 -Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical-scavenging activities of KSO-NLC were 5.43 AE 1.00 mg Trolox equiv. g −1 of NLC and 6.70 AE 0.31 mg Trolox equiv. g −1 of NLC, respectively. The Sun Protection Factor (SPF) of KSO-NLC, 41.38 AE 6.03 with a UVA/UVB ratio 0.64 AE 0.01, suggested a good photoprotective effect. The sustained release of Univul A plus B from KSO-NLC accompanied by its entrapment efficiency up to 64.09 AE 0.98% and drug loading (DL) of 32.05 AE 0.49% (maximum 50% DL capacity) proved that the degradation of the ultraviolet (UV) filter could be reduced. Therefore, the KSO-NLC sunscreen was a feasible solution for the photoprotective approach by using unconventional plant seed oil with a significant enhancement (P < 0.05) in many aspects compared to the formula without KSO incorporation. Keywords Particle size Á Polydispersity index (PDI) Á Uvinul a plus B Á Entrapment efficiency (EE) Á Drug loading (DL) J Am Oil Chem Soc (2019) 96: 201-211.

Pumpkin seed oil (PSO) with carnauba wax and beeswax was used to develop nanostructured lipid carriers (NLC) loaded with a UV filter, Uvinul ® A Plus B. The aims of the study were to optimize the concentration of PSO to develop a stable NLC formulation, determine storage stability of the NLC with and without PSO, and the synergistic effect of PSO-NLC with UV filter for photoprotective properties. The physical properties of NLC were optimized based on the mean particle size, polydispersity index, and storage stability. The optimized NLC consisted 10% lipid phase (3.5% carnauba wax, 3.5% beeswax, and 3.0% PSO) and 90% aqueous phase. After optimization, Uvinul ® A Plus B was added in the optimized PSO-NLC to produce a photoprotective formulation. Uvinul ® A Plus B consisted of both UVA (Diethylamino Hydroxybenzoyl Hexyl Benzoate) and UVB (Ethylhexyl Methoxycinnamate) filters. The NLC produced with PSO and Uvinul ® A Plus B had mean particle size of 135 AE 2 nm and showed good physical stability under storage time. Besides that, the NLC produced also proven to have positive effect in enhancing the entrapment efficiency and drug loading, which were 82.86 AE 0.15% and 55.41 AE 0.04%, respectively, and showed sun protection factor value of 16.61 AE 3.45. The results indicated the presence of synergistic effect among the PSO-NLC with Uvinul ® A Plus B.

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The application of a nanostructured lipid carrier (NLC) to ultraviolet (UV) filter encapsulation was found to enhance its safe use. In this work, a kenaf seed oil‐NLC (KSO‐NLC) coloaded with 1% diethylamino hydroxybenzoyl hexyl benzoate and 1% ethylhexyl triazone was used as an active ingredient in α‐tocopherol cream to develop a photoprotective prototype. It was then subjected to further analysis to determine its physical properties, storage stability, and cytotoxicity. The ratio of KSO‐NLC to α‐tocopherol cream was optimized based on the sun protection factor (SPF) value using a UV transmittance analyzer. The physical properties of the samples were analyzed, and the amount of α‐tocopherol was quantified by ultra‐high‐performance liquid chromatography. The optimized sample was then evaluated for in vitro antioxidant activities using 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid assays. Meanwhile, in vitro cytotoxicity was studied on a normal human dermal fibroblast cell line using thiazolyl blue tetrazolium bromide and cell counting kit‐8 assays. The sample of KSO‐NLC to α‐tocopherol cream in a ratio of 1:2 (N3) showed SPF value >50. Besides, the samples showed microbial stability and sustainable α‐tocopherol content upon 12 weeks of storage. The cytotoxicity evaluation of N3 and α‐tocopherol cream (N5) showed >100% cell proliferation, which indicated that there is no side effect on the cell growth, while triggering the cell proliferation with the presence of bioactive compounds. Overall, the findings of the study are promising for the development of new sunscreen formulation with the utilization of KSO‐NLC and palm‐based α‐tocopherol cream.