This is single-centre, evaluator-blinded study in healthy adult human subjects. Single 24-hour application of sponsor(s) provided test products along with positive and negative controls will be kept in contact with the skin of subjects under occlusion for at least 24 hours (+ 2 hours). Study can be conducted in multiple groups. Safety will be assessed throughout the study by monitoring of adverse events. 

Subject’s back i.e. between the scapula and waist will be utilised as application sites. Application sites will be evaluated for scoring the reaction, namely, erythema, dryness, and wrinkles on a 0-4 point scale separately for each parameter and oedema on another 0-4 points scale as per the Draize Scale after 30+5 minutes of patch removal, 24±2 hours and 168±2 hours after patch removal. 

26 subjects in the age group of 18 to 65 years with varied skin types (Oily, Dry, Normal and Combination, preferably equal ratio) will be selected according to inclusion and exclusion criteria in the study to complete the required numbers i.e. 24 subjects at the end of the study. Preferably with an equal number of males and non-pregnant/non-lactating females 

Score the reaction, namely, erythema, dryness, wrinkles on a 0-4 point scale separately for each parameter and oedema on another 0-4 points scale as per the Draize Scale.

Four parameters namely erythema, dryness, wrinkles and oedema will be scored separately on irritation scoring sheet, however, the highest score of erythema, dryness and wrinkles will be taken for calculation of Mean Irritation Score (MIS). 

Mean Score for Irritation = Total score (highest score from Erythema, dryness, wrinkles + Oedema) for each sample / Total no. of Subjects.

The Evaluator/Scorer will be blinded to test product assignments and any previous scores. All reasonable attempts will be made to ensure that the same individual will do scoring of all reactions to the test products during the course of the study. If the patch is reinforced with tape, any observed skin irritation that is associated with the tape should be reported separately from that of the patch application area.

The combined mean scores and standard deviation of the 24 subjects will be calculated. 

a)     Positive controls i.e. 1% w/v SLS must give a combined means score of >2.0, 3% w/v SLS must give a combined mean score of greater than 3.0 and Negative control must give a combined mean score of <2. If positive control 1% w/v SLS and 3% w/v SLS give a combined means score less than 2.0 and 3.0 respectively and/ or negative control give a combined mean score more than 2.0, then the test need to be repeated on another newly recruited volunteer’s.

b)     A combined mean score of up to 2.0/8.0 will mean that product is ‘Non-Irritant’.

c)     Usage of cosmetic product with a score up to 4.0/8.0 which is ‘Mildly Irritating’ may be reviewed by manufacturer for safety of the formulation.

d)     No cosmetic product should be marketed which has an irritation score above 4.0/8.0. This product should be considered as an ‘Irritant’.