492 JOURNAL OF COSMETIC SCIENCE study (25). The products were applied every day to the same sites for ten days straight. The actual amount of product applied to the test site each day was 2 g/cm2 . At the end of the study each panelist filled out a permission consent form and a questionnaire. The questionnaire asked the test subjects their opinions about the side effects caused by the formulations when used for chemical peeling. The irritation sensation was evaluated each minute for the first 20 minutes after topical application, using a scale from 0--4. The duration of the irritation sensation in minutes was also recorded. As can be seen from Figure 1, formulations G and GD showed the highest redness, itching, pain, and edema, respectively, when compared to GS and GDS, which contained strontium nitrate, while the peeling effects were a little higher in the cases of GS and GDS. GS in comparison with G alone, markedly (p 0.01) shortened the duration of the irritation sensation from 20.6 ± 3.8 min. to 7 .2 ± 2.6 min., and significantly (p 0.05) reduced the magnitude of the pain sensation at all time points. The study demonstrated that GS and GDS formulations suppressed the sensation of pain, edema, redness, and itching. CONCLUSIONS The current investigations have shown that the choice of preparation conditions for formulations, such as oil phase volume, temperature, mixing rate and time, the addition of electrolytes, the type of mixing shaft, and the densities of internal and external phases, play an important role in the stability of multiple emulsions, which is of prime impor­ tance. After long investigations, optimal conditions were chosen and stable multiple emulsions could be produced with all the ingredients involved in this study. In the second part of the study, after obtaining the stable multiple emulsions, panel tests were 10· 9 8 7 6 5- 4- 3 2- 1 a Effects of glycolic acid on skin Figure 1. Data of multiple emulsion formulations obtained from panel test. G (bar l) GD (bar 2) GS (bar3) GDS (bar 4).

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