Youche requested to supply 35g of a cream containing 20% w/w methyl aminolevulinate for use in a photodynamic therapy clinical trial. You have cetomacrogol cream, BP might hospital pharmacy department and can use this as the cream base. What is the formula for your methyl aminolevulinate cream?
[tex]$\frac{20}{100}=0.2$[/tex]
Answer (2)
To create a 35g cream containing 20% w/w methyl aminolevulinate, you need 7g of methyl aminolevulinate and 28g of cream base. The calculations involve determining the mass of the active ingredient based on the desired percentage and then finding the mass of the cream base by subtracting that from the total weight. Therefore, the formula for the cream is 7g of methyl aminolevulinate and 28g of cream base.
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Calculate the mass of methyl aminolevulinate: 35 g × 0.2 = 7 g .
Calculate the mass of cream base: 35 g − 7 g = 28 g .
The formula for the cream is 7g of methyl aminolevulinate and 28g of cream base.
The final formula for the methyl aminolevulinate cream is 7 g methyl aminolevulinate and 28 g cream base .
Explanation
Understanding the Problem We need to prepare 35g of a cream containing 20% w/w methyl aminolevulinate using cetomacrogol cream BP as the base. This means that 20% of the total weight of the cream should be methyl aminolevulinate, and the remaining 80% should be the cream base.
Calculating Mass of Methyl Aminolevulinate First, we calculate the required mass of methyl aminolevulinate. Since the cream should contain 20% w/w methyl aminolevulinate, we multiply the total mass of the cream (35g) by 20% (0.2).
Mass of Active Ingredient Mass of methyl aminolevulinate = 35 g × 0.2 = 7 g
Calculating Mass of Cream Base Next, we calculate the required mass of the cream base. This is the total mass of the cream minus the mass of methyl aminolevulinate.
Mass of Cream Base Mass of cream base = 35 g − 7 g = 28 g
Final Formula Therefore, to prepare 35g of 20% w/w methyl aminolevulinate cream, you will need 7g of methyl aminolevulinate and 28g of cetomacrogol cream BP as the base.
Examples
In pharmaceutical compounding, calculating the correct proportions of active ingredients and bases is crucial for creating effective medications. For example, a pharmacist might need to prepare a topical ointment with a specific concentration of an antibiotic. By accurately calculating the masses of the antibiotic and the ointment base, the pharmacist ensures that the medication delivers the correct dosage to treat the infection effectively. This precise formulation is essential for patient safety and treatment success.
