THE CLINICAL EVALUATION OF ANTIDANDRUFF SHAMPOOS 451 REFERENCES (1) Van Abbg, N.J. J. Soo. Cosmetio Chemists 15 609 (1964). (2) Spoor, H. J. Proc. Sai. Seat. Toilet Goods Assoc. No. 31 33 (1959). (3) Thorne, N. Brit. J. Clin. Praat. 17 357 (1963). (4) Vander Wyk, R. W. and Roia, F. C. J. Soc. Cosmetic Chemists, 1õ 761 (1964). Introduction by Mr. Van A bbd Unlike our previous paper on the subject of dandruff, we are now dealing with the clinical evaluation of treatments. It would naturally be preferable to carry out a simple laboratory test but this cannot be done with certainty and so we find ourselves in the field of human subjects and biological variation. The real difficulties arise from the fluctuating character of dandruff itself and a relatively sophisticated technique is necessary for validation of the efficiency of a medicated shampoo. In this paper, we have dealt with the 25-area method of inspection that appeared in the last paper and with a more rapid technique where the scalp is divided into only four imaginary areas. Contrary to expectation, the quadrant method appears to be rather more sensitive. There is a general parallellism or, in fact, linearity between the two techniques, over most of the range of moderate to severe dandruff but at the level of high dandruff there is a greater spread out on the rapid method and the displacement from zero at the lower end suggests that the rapid method is also more sensitive at low levels of dandruff. We have distinguished between weekly or fortnightly examinations over a fairly long time and a programme of only three examinations, comprising before treatment, after one month's treatment and after two months' treatment. One way of representing the data obtained from the abbreviated programme of inspection is in the form of a ternary diagram which shows not only improvement of the group but changes in the direction of "worse" or "no change". DISCUSSION MR. C. PucH: When one looks at the ternary diagram, one can see very clearly the proportion of people getting benefit. To my mind this is a most important quantity to examine in trying to make a better shampoo. In Fig. $ one can see that the placebo shows virtually no movement, but the test shampoo is moving firmly towards 100% getting better. If the trial had been continued for another month, the treated panel might have reached the apex, although this is unlikely. I xvould like to stress that this seems to be an excellent method of presentation giving far more valuable information than percentage improvement on an "average head". MR. VA• ABBr.: Although curves such as those represented in Fig. •t appear to show clearly what is happening week by week, they represent panel averages and they do not show the proportion getting worse or the numbers unchanged. For our ternary diagram, we have arbitrarily chosen a level of 50% improvement or 100% worsening as the level for illustration. However, we could have chosen other levels and shown the appropriate proportions. The actual points on the diagram would differ but the conclusions regarding superiority of treatment-v-placebo would not materially change. MRs. D. L. WEDDERBUR•: You could, perhaps, have omitted a control group in this trial owing to your employment of control and then test and then back on control again. Does your use of a placebo mean that you have found seasonal variations in

452 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS dandruff and that you regard it as necessary to have a control group in parallel because the incidence of dandruff fluctuates at different times of the year? MR. VAN ABBg: The dandruff level of untreated subjects does not seem to be dependent on the season but we did see a sign in our earlier work that under active treatment there was a seasonal influence. Other factors might be involved too, such as holidays, examinations and various psycho-somatic influences that could make it difficult to draw conclusions without a placebo. M•ss DEAN: I should like to add that although we carry out concordance tests between examiners, this does not safeguard against all the examiners drifting in the same direction over a period of time. If we run a control panel, the observers do not know which product is control and which is treatment, so it does help to safeguard against any drift of this nature. Of course, using a placebo does put some people off they realise they are not getting better, and sometimes a proportion of our subjects get discouraged and tend to default if we keep them too long on no-treatment. MR. I(. M. GODFREY: IS the time required to re-establish dandruff affected by residual absorption of the active ingredients? MR. VAN ABsg: Possibly. Zinc omadine (the active ingredient referred to in the paper) is only soluble in water to the extent of about 6 ppm. Nonetheless it is soluble to this extent and may be absorbed or adsorbed this may contribute towards its efficacy, for some of it may be taken up during treatment and not be eluted for some time afterwards. MRs. S. M. LUDFORD: DO yOU use people again for assessment once they have recovered to their pre-treatment level if so, do they respond differently from new subjects? Do you observe any other effects of antidandruff products or do you only look for effect on dandruff? Mms DEAN: Occasionally we do use subjects again. We allow a considerable recovery period and, when using them again, we take great care to stratify them between the groups. We have supplemented the clinical examinations by looking for effects on Pityrosporurn and bacterial counts on the scalp. We pass an applicator through the subject's hair and take plate counts of micro-organisms. Sometimes we find a reduction but so far we have not really demonstrated any definite correlation with dandruff scaling. MR. VAN Assi: We also record itching and erythema, again without showing any distinct correlations. MR. K. V. CURRY: IS the response of the moderate/severe group of subjects similar to the response of the "very slight" group? I have a feeling that the majority of people with dandruff have the second type which is really a social nuisance rather than a scalp disorder. M•ss DEAN: On the whole it is easier to show a significant reduction on people who have severe dandruff and for the bulk of our panels we prefer to use such subjects. I think the proportion showing a reduction who start with slight dandruff is nearly as great as for those who start with a severe level but, of course, it is not such a great reduction. MR. R. CLAm•: Is your objection to the use of vacuum cleaner technique purely theoretical or is it based on practical experiments?