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Question

Posted on: March 6 2013

Why does the order of addition have an influence in the next regulation?

Ventolin Sir 150ml promethazine HCl 225mg pseudoephedrine 450mg distilled water 15ml folcodine 225 mg, ethanol 94 ° 2, 7g dt 150ml < br/> It would be important to first dissolve the promethazine and pseudoephedrine in water and then Ventolin before adding the folcodine in alcohol. If the ventolin were to be added last (i.e. after the pholcodine), a precipitate would occur. What can be the explanation for this? What can precipitate in this preparation, is that Promethazine base? Is it not necessary to add citric acid or ascorbic acid to this preparation as an anti oxidance to protect the promethazine?

Answer

Ventolin Syrup is a solution of salbutamol sulfate. The solubility of salbutamol base is minimally in water (3MG/L) and therefore the solution of salbutamol sulfate should be at least slightly acidic. For this purpose, the company uses a buffer citric acid/citrate with presumably a prevalence of citric acid. I suspect you have pseudoephedrine HCl (PE. HCl) have been used together with promethazineHCl (PR. HCl). Under the influence of the base Folcodine develops pseudoephedrine and promethazine. From the first I do not find values for solubility in water but if I pull the line through from ephedrine, then it is supposedly soluble in water. This is not the case for Promethazine base. If you are after solving PE. HCl and PR. HCL adds Ventolin syrup then you have a acidified solution that neutralizes the Folcodine base and thus you will not get any precipitation. It is indeed consulted to add an Antioxydans for PR. HCl. Citric acid already sticks in the solution. I would add 0.5 g Vit C and wait and see how the solution behaves during custody. This can be added to the solution of PE. HCl and PR. HCl in water.