]. Soc. Cosmetic Chemists 18 663-679 (1967) •) 1967 Society of Cosmetic Chemists of Great Britain The potential irritancy to the rabbit eye mucosa of commercially available cream shampoos R. E. DAVIES and K. H. HARPER* Presented at the Symposium on "Product Testing", organised by the Society of Cosmetic Chemists of Great Britain in Eastbourne, Sussex, on 15th November 1966. $¾n0p$l$--A study has been made of the irritancy to the rabbit eye mucosa of five commer- cially available cream shampoos, employing four different screening procedures. It is con- cluded that all five shampoos are "irritants" to the rabbit eye mucosa. Three show severely irritant properties and one other clearly falls under suspicion in this respect. Results obtained by the different methods are discussed. INTRODUCTION In 19133 two of us from this laboratory were privileged to address this Society on the question of the reactions elicited in the rabbit eye on application to the cornea and coniunctivae of a selection of commercially available shampoos (1). Although the primary purpose of that talk was to present comparative data produced by several methods of assessment, we also drew attention to the fact that the two cream shampoos tested were considerably more irritant than any of the liquid formulations. We observed, however, that prior dilution of the cream shampoos with water- to a concentration of 10% - minimised the irritancy in one instance, and exaggerated it in the other. As a general rule, other tests with cream formulations (not reported at that particular meeting) confirmed that a diluted form of the cream shampoo exhibited greatly reduced irritancy under the conditions of the test, and the question of whether or not prior *Huntingdon Research Centre, Huntingdon. 663

664 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS dilution of the shampoo might provide a more practical assessment of the user hazard came up for discussion in the Toxicology Subcommittee of this Society. However, at that time it was acknowledged that the paucity of the data on experimental animals precluded the drawing of any real conclusion and the question was left in abeyance until such information should be made available. The purpose of this communication is therefore twofold. In the first instance we wish to report on the reaction of the rabbit eye mucosa to a selection of cream shampoos currently available in this country. In the second, we wish to continue our comparison of the different test methods for appraising irritancy. EXPERIMENTAL DETAILS Five cream shampoos were purchased from shops in Huntingdon, coded as shampoos A to E and all identifying marks removed. The code was not broken until completion of the investigation. A total of 18 rabbits of a New Zealand White strain was used to test each sample. The procedure followed was identical with that used in the earlier studies (1). Rabbits 1- 6: Sample instilled, no further treatment. Rabbits 7-12: 10% dilution of sample instilled, no further treatment. Rabbits 3-15: Sample instilled, eye irrigated with 20ml water at 2 sec. Rabbits 16-18: Sample instilled, eye irrigated with 20ml water at 4 sec. (a) Rabbits 1 - 6 provided the design for the "FDA test". (b) Rabbits 1, 2 and 4, plus rabbits 13-15 and rabbits 16-18, provided the design of the "Draize test". (c) Rabbits 7-12 provided an assessment of the effect of dilution of the sample (dilution test). (d) Rabbits 3 and 5, together with rabbits 16 and 18 represented the abbreviated Draize test used on occasions by us as a preliminary screen (HRC screen). In all cases the eyes were scored by the system devised byDraize (2). In interpreting the results obtained we used the following arbitrary classi- fication in addition to the irritancy definitions given by the official test procedures. 1. Non-irritant - no reaction at any time. 2. Slightly irritant - reaction confined to the conj unctivae and persisting for up to 5 days only.