Question
Posted on: March 6 2013One asks me to put together a (preferably thicker) CR è me with the following ingredients (narcotic Cr è me for minor beauty interventions). This CR è me was previously ordered somewhere else
And this is the composition that has been given:
benzocaine 20%< BR/> Given the high concentration of active substances, I ask questions concerning the CR è mebasis (should not be a real ointment, but thicker cream) and shelf life. I started with the PEG ointment from the dermatics and got 10% water attached (dissolve lidoc and Tetrac); Then the benzocaine with the base mixed and through the ointment grinder. At first it went well, but In the end the ointment became too liquid. I have been able to partially remedy this by adding 5% cetyl alcohol, but after a few days there has been a certain degree of demixing. Currently I have reduced the water and increased the cetyl alcohol, which seems to give a more stable creme. Like your advice.
lidocaine 6%
tetracaine 4%
emulsifier
cr è mebasis
Answer
The fact that the ointment is more fluid is probably the result of solving the active ingredients, which are present in high concentration and are likely to be soluble in PEG. Therefore, I would not add water. If the ointment is too liquid, you can still adjust the amount of PEG 4000 or 6000.