Question
Posted on: March 6 2013Can Carbomeergel be used together with salicylic acid? Salicylic Acid 3% hydrophilic gel AD 100g
When rubbing carbopolgel with salicylic acid, the gel became very liquid. After addition of the 3g Trometamol this was back more vaster. But is the salicylic acid still present in its acidic form? And if not: Is it still efficient?
Answer
You have it at the right end. By adding trometamol, in order to restore the viscosity, both carbomer and salicylic acid react with this base.
Consequently, Carbomeergel is not the good Excipi ë ns. Use a hydroxypropylcellulose (HPC) gel.
Consequently, Carbomeergel is not the good Excipi ë ns. Use a hydroxypropylcellulose (HPC) gel.
R/Hydroxypropylcellulose (Klucel) 3.0 g glycerol 10.0 g sorbic acid 200 mg water 30.0 g alcohol up to 100.0 G
Modus Operandi
- tarreer a beaker with rudder rod and note the tare weight (T)
- rub HPC and sorbic acid with glycerol in this tarred beaker and add alcohol in small fractions and mix. Since it is not certain that we obtain a clear gel, I suggest starting with 60 g to add alcohol. Once this gel is finished, place beaker + stirring rod on a balance and add very gradually under good stirring water to (T + 100 g). Check that the gel becomes cloudy.
- The gel becomes cloudy add 10mL extra alcohol, followed by re-adding water. Check if the gel remains clear if not again a small amount (5 ml) of alcohol should be added. Does not exceed the weight = (T + 100 g)!