Question
Posted on: March 6 2013How to prepare best: Salicylic acid 5 G Clobetasoldipropionate 50 mg Carbopol 300 mg NaOH 2N 1.5 ml NaEDTA 150 mg isopropanol 28 g Aqua conservans up to 100 g
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Answer
Comment:
In This composition, which is analogous to a formula from the TMF, is a first problem the incompatibility between salicylic acid and Carbopol. After all, the acid groups of both products go into competition with each other for the base, which is added to bring the Carbopol into the salt shape so that it swells. When adding extra base, all salicylic acid will be converted into salicylate. This is certainly not the intention. The second problem is the adjustment of the amount of isopropanol so that salicylic acid and clobetasoldipropionate are dissolved. In this context, the very high concentration of salicylic acid is present. If we reduce it to 3% as in the TMF then an alcohol level of 70 ° can be used.
In This composition, which is analogous to a formula from the TMF, is a first problem the incompatibility between salicylic acid and Carbopol. After all, the acid groups of both products go into competition with each other for the base, which is added to bring the Carbopol into the salt shape so that it swells. When adding extra base, all salicylic acid will be converted into salicylate. This is certainly not the intention. The second problem is the adjustment of the amount of isopropanol so that salicylic acid and clobetasoldipropionate are dissolved. In this context, the very high concentration of salicylic acid is present. If we reduce it to 3% as in the TMF then an alcohol level of 70 ° can be used.
Solution:
Tarreer a glass recipi ë nt with wide neck (jam jar) of 150 ml together with a glass rudder and apply 5 G Hydroxypropylcellulose 400, 3 G salicylic acid and 50 mg clobetasoldipropionate. Mix these powders with the rudder rod and add 70 ml isopropanol. Mix and place the closed recipient in the refrigerator for 2 hours. Fill up to 100 g with freshly boiled and cooled purified water and homogenize. Complete the preparation in a tube.