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VG ☆ India, 2012-07-30 09:02 (4661 d 00:44 ago) Posting: # 8993 Views: 8,170 |
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Dear all Could any one explain the following: How to calculate Cmin manually. What are the input data required for Cmin calculation. What is the current thinking of Cmin with regards to 90 % CI as per current EMA requirements. Is it to be calculated or not? Regards VG Edit: Category changed. [Helmut] |
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RVR ☆ India, 2012-07-30 13:51 (4660 d 19:55 ago) @ VG Posting: # 8994 Views: 7,171 |
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Dear VG, ❝ How to calculate Cmin manually. Cmin is a steady state parameter – It is the minimum or “trough” concentration (Cmin) of a drug observed after its administration and just prior to the administration of a subsequent dose. (Units -Amount/Volume). Cmin can be calculated manually from the obtained Bio-anlaytical concentration data - The first measured concentration of drug after the drug administration is the Cmin concentration for first dose and last measured concentration of the first dose will be the Cmin for the second dose of drug and the last measured concentration of the second dose will be the Cmin for the third dose … (steady state). Formulae for calculating Cmin = Accum x Intercept x (e-lzT - e-kaT) ❝ What are the input data required for Cmin calculation. Input data for PK analysis will be the Bio-analytical data for Cmin calculation by using PK software. Manual procedure is already stated above. ❝ What is the current thinking of Cmin with regards to 90 % CI as per current EMA requirements. Is it to be calculated or not? As per current EMA guideline Cmin is not needed to be calculated for Immediate release formulation with regards to 90% CI (CPMP/EWP/QWP/1401/98 Rev. 1/ Corr) reference Cmin is to be calculated for Modified release formulation with regards to 90% CI (Modified release guideline - CPMP/EWP/280/96 Corr) reference If the reference links does not work, please input italic words in the google to find the reference articles. Regards, RVR |
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VG ☆ India, 2012-07-31 13:14 (4659 d 20:32 ago) @ RVR Posting: # 9000 Views: 7,097 |
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Dear RVR Thanks a lot for the responses. In a case for multiple dosing steady state study for one of the MR formulations with a dosing interval of 24 hours and the pre-dose samples were collected for 7 days and serial sampling till 24 hours on the 7 day. Which all time points will be used for Cmin calculation. How should we calculate the Ka (absorption constant here) to be used in the formula for Cmin calculation Regards VG |
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d_labes ★★★ Berlin, Germany, 2012-07-31 15:33 (4659 d 18:13 ago) @ RVR Posting: # 9003 Views: 7,080 |
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Dear RVR, dear VG, ❝ Cmin can be calculated manually from the obtained Bio-anlaytical concentration data - The first measured concentration of drug after the drug administration is the Cmin concentration for first dose and last measured concentration of the first dose will be the Cmin for the second dose of drug and the last measured concentration of the second dose will be the Cmin for the third dose … (steady state). ❝ ❝ Formulae for calculating Cmin = Accum x Intercept x (e-lzT - e-kaT) Seems a little bit strange for me  .We had a lot of discussions here in the forum regarding the metric Cmin. There you will find some more reliable definitions how to get Cmin in steady state. Please do us the favour and search the Forum first before asking. For an appetizer see this thread. — Regards, Detlew |
Ing. Helmut Schütz