The Sun Protection Factor And Protection Factor Of Ultraviolet A Detection Of The Sunscreen And Its Application Method Research

Objective:1. Research the relationship between the SPF values/PFA values and the amount/time of sunscreen applied.2. To discuss the proper method to using the sunscreen. Method:1.The preparation of standard reference sunscreens. It was prepared according to the international sun protection factor (SPF) test method,2006 and the Hygienic Standard for Cosmetics,2007 Guide to the preparation of SPF 15 and PFA4 standard reference sunscreens.2. ultraviolet irradiation. a. On the basis of different amounts but identical time:①SPF 15 standard reference sunscreens were used as standard control, and two commercial sunscreens(SPF30,SPF60) were applied 15 minutes before irradiation which can arise the minimal erythema dose in different amounts as below:0.5,1.0,1.5,2.0 and 3.0mg/cm2 seperately. Calculated the SPF values of different amount of sunscreen applied. Get the best fit dose.②PFA4 standard reference sunscreens were used as standard control, and commercial sunscreen (PFA8) was applied 15 minutes before irradiation which can arise the minimal persistent pigment darkening dose in different amounts as below seperately:0.5,1.0,1.5,2.0 and 3.0mg/cm2 seperately. Calculated the PFA values of different amount of sunscreen applied. Get the best fit dose. b. On the basis of the different time but identical amounts:chose the best fit dose as standard.①SPF15 standard reference sunscreens were used as standard control, Two commercial sunscreens(SPF30,SPF60) were applied in Optimal dose after interval different time as follows:20.40.70. 100 and 130 minutes seperately, then gave the iradiation which can arise the minimal erythema. Calculated SPF values of different time.②PFA4 standard reference sunscreens were used as standard control, the commercial sunscreen (PFA8) was applied in Optimal dose after interval different time as follows:20.40.80.110 and 150 minutes. then gave the irradiation which can arise the minimal persistent pigment darkening. Calculated PFA values of different time of sunscreen applied. Results:1. when applied with different amounts of sunscreen and irradiated by irradiation which can arise minimal erythema, The relationship between sunscreen amount and the SPF is significantly linear. While increased the amounts, SPF values was become higher. The SPF values were increased obviously when sunscreen amount was between 1.5mg/cm2 and 2mg/cm2. While continue increasing sunscreen amount, SPF values were slightly increased. When the amout was 2mg/cm2, the Measured SPF values was close to the SPF values given on the sunscreen container. The statistical analysis showed no significant difference. Therefore, the optimal dose was 2mg/cm2. Furthermore, the higher the SPF values, the more obviously decreased with the decreased amounts.2. The relationship between sunscreen amount and the PFA is also significantly linear. With the increased of amounts applied, PFA values were become higher apparently. The PFA values were significantly increased when sunscreen amount was between 1mg/cm2 and 2mg/cm2. Continue increasing sunscreen amount, PFA values were obviously increased. Similarly, applied amount was 2mg/cm2, the measured PFA values slightly lower than the PFA given on the sunscreen container. From the curve which display the relationship between PFA values and the amount of sunscreen applied, we can be clearly obtained that the optimal dose was 2mg/cm2.3. the relationship between SPF values and the time of sunscreen applied is significantly linear. When the interval time were 20.40 and 70 minutes, the Measured SPF values were close to the SPF given on the sunscreen container. The statistical analysis showed no significant difference. When interval time was 100 minutes, the Measured SPF values significantly lower than the SPF given on the sunscreen container. When interval time was 130 minutes, the measured SPF values were more lower. With the past of time, the SPF values decreased gradually. The SPF values were significantly decreased when the interval time was between 70 minutes and 100 minutes. Furthermore, With the past of time, the higher the SPF values was, the more obvious it decreased.4. the relationship between PFA values and the time of sunscreen applied was significantly linear. With the past of time, the PFA values was decreased gradually. The PFA values were significantly decreased when the time of sunscreen applied was between 80 minutes to 110 minutes. Conclusion:1. The amount of sunscreen applied on the skin should be 2.0mg/cm2 to establish protection corresponding to the SPF given on the sunscreen container.2. Commercial sunscreens should be used once per 70～80 minutes in daily life to ensure its effectiveness.