Calculation of Vitamin D3 on HPLC
Posted: Wed Oct 31, 2012 4:29 pm
Hello all,
I now would like to see if my calculation is correct for the USP Vitamin D3 assay by HPLC:
I transfer the equivalent of 5 capsules to a glass bottle and record the weight in ug. I perform the method extraction and inject my samples. I average the areas of my vitamin D3 samples and get the rsd for my intra-assay precision. I calculate the concentration of my standard and make the correction for purity. The nominal concentration of Vit D3 that should be in the sample is then calculated by:
(Weight of sample transferred/Net fill calculated per cap) X (the nominal label claim)
100 ml
I divide by 100 ml since my sample is filled to 100 ml volume. Is this the correct way to calculate the nominal concentration of Vit. D3 that should be in my sample? I use the USP formula to calculate the formula % of Vitamin D3. This % is then multplied by the conc. of my vit D3 standard (since this is considered 100% right ??) to give me the Vit D3 conc in ug/ml of my sample. The ug/ml is then converted into IU/ml. The calculated IU/ml is then divided by the weight of sample which was transferred to the glass bottle to get the IU/ug. To get IU/cap, I multiply (IU/ug) x (ug/cap) (which was calculated by obtaining the net weight of the capsule). Please let me know if you see anything that is incorrect. Thanks so much !!!!
I now would like to see if my calculation is correct for the USP Vitamin D3 assay by HPLC:
I transfer the equivalent of 5 capsules to a glass bottle and record the weight in ug. I perform the method extraction and inject my samples. I average the areas of my vitamin D3 samples and get the rsd for my intra-assay precision. I calculate the concentration of my standard and make the correction for purity. The nominal concentration of Vit D3 that should be in the sample is then calculated by:
(Weight of sample transferred/Net fill calculated per cap) X (the nominal label claim)
100 ml
I divide by 100 ml since my sample is filled to 100 ml volume. Is this the correct way to calculate the nominal concentration of Vit. D3 that should be in my sample? I use the USP formula to calculate the formula % of Vitamin D3. This % is then multplied by the conc. of my vit D3 standard (since this is considered 100% right ??) to give me the Vit D3 conc in ug/ml of my sample. The ug/ml is then converted into IU/ml. The calculated IU/ml is then divided by the weight of sample which was transferred to the glass bottle to get the IU/ug. To get IU/cap, I multiply (IU/ug) x (ug/cap) (which was calculated by obtaining the net weight of the capsule). Please let me know if you see anything that is incorrect. Thanks so much !!!!