Of dermatologist during consultation: Shampoo simplex with 5% salicylic acid and 5% L.C.D. How is it that this shampoo foams in some pharmacists and not in other pharmacists?

Give an answer based on theoretical considerations is not easy. I can give some possibilities for a difference in foam power.

There are three possibilities to process the unresolved part of the salicylic acid in this preparation.

1. The simplest method is salicylic acid simply suspending. If the sedimentation of the salicylic acid gives problems then one may consider adding a viscosities enhancement substance. One could opt for methyl cellulose, which has itself Tensio-active properties. But the viscosity of the shampoo can already be quite high.
2. the second possibility is this of solving the salicylic acid. Of course, a fair amount of alcohol should be added. The added alcohol will certainly result in a reduction in foaming.
3. solubilizing of the salicylic acid is the last possibility. For this, Cetomacrogol is added in a quantity of 2 to 4 X the amount of salicylic acid. Cetomacrogol means an additional surface active and a reduction in the foam power is not expected.

The question also needs to be asked how colleagues interpret the term "shampoo simplex". The original is the formula Herdewijn. But would all those still compose? Is there any shampoo simplex of Certa (fabrication Conforma)? In any case, this shampoo simplex has nothing to do with the formula herdies, which does not mean that it does not frother. I also don't know how that shampoo reacts to the addition of salicylic acid and LCD.