samples were dispersed in 100 ml of distilled water and were homogenized by ultrasonication for 5 min. The obtained dispersion was filtered with a filter paper and the first 10 ml was rejected. Then 2 ml of filtered solution was adjusted to 50 ml using distilled water. The absorbance of each sample was determined by spectrophotometry in the range of 290–320 nm (UVB), with 5 nm intervals, using distilled water as blank. A fresh sunscreen sample (not submitted to temperature effect) was used as control, in order to establish initial SPF. Three replicates of each group were performed. The SPF of each sample was determined with the data obtained by spectrophotometric analysis, using the Mansur equation: