Question
Posted on: March 6 2013I got following prescription: Metronidazole 800 mg La Roche-Posay Hydranorme Cream 40 ml
The composition of the Hydra standard CR è me according to the Pharmacompendium 2004 is: w/O emulsion based on: Aqua, Squalane, paraffin liquidum, Cera Alba, Sorbitan oleate, and acid, glycerin, magnesium sulfate, dehydroepiandrosterone acetic acid, Phenoxyethanol and perfume.
I inrubbed the metronidazole in this CR è me and brought it through the three Walsmolen. The CR è me seemed to be in order and she was delivered. But after the weekend, the Pati ë NT came back with a tube in which a broken emulsion was.
I inrubbed the metronidazole in this CR è me and brought it through the three Walsmolen. The CR è me seemed to be in order and she was delivered. But after the weekend, the Pati ë NT came back with a tube in which a broken emulsion was.
Answer
I suspect there is a certain degree of reaction between the base metronidazole and the stearic acid, in which a certain amount of metronidazolstearate is formed. This reaction product will have O/W emulgatorical properties. And this leads to breaking of the emulsion. I can hardly judge the effect of the three-walsmolen, but I certainly do not see it as the primary cause.
there are several solutions. If one adheres to the prescribed basis then adding additional W/O emulsifier like Arlacel C MAY cause the case to straighten again; This should of course be tried out; Maybe on the failed copy.
a second possibility exists in the use of a W/O product without stearic acid like e.g. petroleum jelly with Sorbitansesquioleate + water from the TMF. Probably not as elegant as the brand product.