I want to calculate drug content to calculate entrapment efficacy from nanoparticles could anyone let me know how to calculate it from supernatant layer after centrifugation?
1. Prepare a calibration curve with molecule of choice in the same solvent as the supernatant. The molecule should have a peak somewhere from 200 to 800nm for a usual uv spectrophotometer. The relation should follow beer-lambert relationship. A=ecl where A rep absorbance, e rep molar extinction coeff, c rep the conc of the solution, l rep the path lenght of the cuvette which is typically 1cm.
2. Measure the absorbance at the chosen peak. Back calculate the concentration.
3. The rest is simple subtraction.
First amount of drug not encapsulated should be calculated as Xian explained above. Then amount of drug encapsulated will come to know. The dry powder can be soaked in a suitable media over the night after crushing the particles. The content is filtered and amount present can be estimated by suitable method. Hope it will help you to workout. Please don't forget to upvote the answer.
Follow the suggestions by Drs. Patil and Xian. Hope that solves your problem, if not post with details exact procedure you followed and the result you got! This one is quite simple and straight-forward. The calibration curve method is the standard way with UV-Vis spectrophotometer and had always provided the correct, in terms of nearest possible and LOD verified answer!
Firstly, you must have a standard solution (have the same active ingredient with the drug) that you know the concentration. And then you must prepare sample solution (same concentration). Theoretically, there is formulation information such as 1g gel contains 250 mg drug. You must calculate how much mg you must weight.
You must calculate a calibration value. Standard solution concentration/ theoretical sample concentration x standard active ingredient activity x (if there is a transforming factor) x theoretical drug amount value. This is your calibration value.
And there is scale factor too. The real sample amount/ theoretical sample amount.
So you choose your wavelength, you do zero with the blank solution and then you read standard sol. and sample sol.
Active ingredient in the drug = Sample absorbance/ standard absorbance x calibration value x scale factor
Note: You must regulate both sample and standard sol. concentration as the max absorbance peak is max 1.
How can I calculate the amount of drug present in a proniosomal gel using UV spectroscopy? - ResearchGate. Available from: https://www.researchgate.net/post/How_to_calculate_the_amount_of_drug_present_in_a_proniosomal_gel_using_a_uv_spectroscopy [accessed Jun 12, 2016].
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