Question
Posted on: March 6 2013How can I best perform the following recipe for an ear drop? Triamcinolonacetonide 10mg Salicylic Acid powder 100mg Benzalkonium chloride 5mg Antiseptic Solution 94 ° 5ml
Aqua purificata ad 10ml < br/> I thought that Benzalkonium chloride (BzCl) was incompatible with salicylates. By which preservative can I replace this and in what concentration? In Martindale It is also stated that Triamcinolone acetonide is insoluble in water and only slightly soluble in alcohol.
Answer
With Salicylates BzCl will be incompatible but if this is also the case with salicylic acid I do not know. This should be tested out. If we assume that this is the case then we can assume that with 50% antiseptic solution a preservative will be superfluous. The whole becomes so who a suspension, given the insolubility of Triamcinolone acetonide and the fact that you will have to use a trituration to weigh this small amount off. I also don't know if 100mg of salicylic acid dissolved in 5ml antiseptic solution will continue to dilute with water in solution. Use 0.25 à 0.5% hydroxypropylcellulose as a thickening agent.