Evaluation of depilatories (IS: 9636-1988)

Evaluation of depilatories (IS: 9636-1988)

This standard prescribes requirement & methods of sampling & test for chemical depilatories having alkaline thioglycollic composition. This standard does not cover depilatories having metallic sulphides & stannites composition.

Requirements are: The depilatories should be in the form of cream or lotion. It should be colorless & shall not emit foul smell & acceptable chemical depilatories formulation should follow the following attributes:

a.) It should convert human hair completely in about 10 minute to a soft plastic mass which may be easily removed from skin by wiping or rinsing.

b.)It should be non-toxic on skin even on long contact.

c.) It should be easily applied, cosmetically elegant & pleasantly perfumed.

d.)It should be stain free on clothing.

e.) All the raw material used shall confirmed respective Indian standard specification.

f.) Depilatories are in the form cream & lotion having thioglycollic acid composition shall compiles with following requirements

i.)        pH range should be 11-12.7

ii.)       Presence of calcium thioglycollate, calculated as thioglycollic acid present by mass (2.5-5%)

iii.)      thermal stability: it should be passed test for thermal stability

g.) material should be packed well closed container & lacquers (aluminum collapsible tube)

On the label

The following instructions shall be on container or leaflet supplied with the pack

a.) Never use the material inflame or broken or near eyes

b.) Should this occur, wash with lukewarm water (cold water)

c.)  If used for first time, carry out the following test: used a little hair remover over 5 cm² of skin on inner elbow. If 24 hours later if skin is normal, material may be safely used.

Determination of pH

A pH meter is required which is equipped with glass electrode. pH shall be determined directly in case of cream or lotion using pH meter with a glass electrode.

Determination of calcium thioglycollate

Reagents required: Conc. HCl, standard I₂ solution (0.1 N), and starch as indicator 0.5% w/v.

Procedure: accurately weighed about 5 gram of sample in a 250 ml conical flask. Add about 75 ml of water & 15 ml of conc. HCl. Heat on water bath for 10 minutes. Cool & titrate with iodine solution using starch solution as indicator.

Calculation: calculate on the basis each ml of 0.1 N solution of iodine equivalent to 0.00921 gm of thioglycollic acid.

Thermal stability

Fill a clear glass round bottle of about 45 ml overflow capacity with the material & closed tightly. Heat the bottle at 37± 1^oC for 16 hours. Material shall be considered pass the test no separation is observed.