Anyone plz tell me calculations for drug content of tablet?

Anyone plz tell me calculations for drug content o f tablet ?
Estimation of Drug Content
Accurately weighed ten indomethacin tablets, powdered them and mixed properly. A portion of powdered tablets (weighed equivalent to 20mg of indomethacin) was added to volumetric flask (100ml) and 0.1 N methanolic HCl (60ml) was added. The mixture was sonicated for 10 to 15 min and volume was made up by 0.1N methanolic HCl. 2ml of this solution was added to volumetric flask(100ml) and volume was made up to 100ml by 0.1N methanolic HCl. The resulting solution was analyzed at 318nm and drug concentration was determined.

How can you call yourself an ‘analytical chemist’ if you don’t know this answer? It is;

Indomethacin Concentration (mg/mL) = (RU/RS) × (CS/CU) × 100 mL x 100 mL/2 mL
RU = Peak response of Indomethacin from the Sample solution
RS = Peak response of Indomethacin from the Standard solution
CS = Concentration of the primary Indomethacin RS in the Standard solution (mg/mL)
CU = Concentration of Indomethacin in the Sample solution (mg/mL)

Indomethacin Potency (mg/tablet) = [Indomethacin Concentration (mg/mL) x 100 mL] x 20 mg/10 tablets

% Label Claim = 100% x Indomethacin Potency (mg/tablet)/Target Potency

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I think I understand your background and this question. This method is adapted from the USP monograph for Indomethacin Capsules (a different dosage form!). Thus, grinding tablets. Therefore;

  1. You NEED a reference standard that has been similarly treated as the sample.

  2. It is based on the linear equation known as the Beer-Lambert law, where A = abc or
    Absorbance = absorptivity x pass length (1 cm) x concentration (mass/volume)

  3. This method has not been validated as per ICH Q2(r1), though I am sure it will pass for Indomethacin.
    My greatest concern is grinding (you can lose dust) and specificity (interferences in the tablets). Thus, I
    prefer a whole tablet assay.

  4. It does not comply with various monographs on ‘content uniformity’ of the tablet.

  5. This method does not comply with ICH Q3 on related substances. Only chromatography (probably
    HPLC) can quantitate down to 0.05% of the tablet’s ‘maximum daily dosage’.

As you can see your giving a regulatory reviewer a ‘lot’ of bullets to shoot you! NOT a good idea!

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