Determination of the Sun Protection Factor of Red Ochre, various Namibian Seed Oils, and the Subsequent Development of a Lip Balm

Abstract

The research aim was to formulate a novel lip balm, using natural products from Namibia. Samples were formulated containing red ochre at different concentrations in either a petroleum jelly base or a zinc oxide (15%) ointment base and assessed for Sun Protection Factor (SPF) activity. The SPF absorbance values of various Namibian seed oils such as ximenia, marula, Kalahari melon, and baobab oil were also determined by UV spectrophotometry. The absorbance values were recorded and substituted into the Mansur equation to calculate the SPF of each sample. The SPF of the standards, zinc oxide ointment British Pharmacopoeia (BP) base and petroleum jelly were 24.0 and 0.6 respectively. The sample with 5% red ochre in petroleum jelly had an SPF of 1.6 and the sample with 10% red ochre in petroleum jelly had an SPF of 3.4. The sample with 20% red ochre in petroleum jelly had an SPF of 12.7, while the sample with 50% red ochre in petroleum jelly had an SPF of 13.2. The 10% red ochre in zinc ointment BP base had an SPF of 11.4, while the 20% red ochre in zinc ointment BP base had an SPF of 28.7. Ximenia oil had the highest SPF of 11.5. Marula oil had an SPF of 0.5, Kalahari melon oil 2.9, and baobab oil 2.7. Therefore, the optimal formulation to use was 20% red ochre and 20% ximenia oil in a zinc ointment BP base.