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Phaneendra.K ☆ 2010-12-27 07:05 (5655 d 07:30 ago) Posting: # 6341 Views: 5,921 |
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Hello everybody, let me introduce to you. I'm Phani and i am new to this forum. I hope this would fortify my knowledge. How are the time Points of Blood collection from the subjects designed. Why is it that the frequency of collection is not the same for all the drugs? Generally the pattern of collection is 00:00. 00:30, 01:00, 01:30, 02:00, 03:00, 04:00, 08:00, 12:00, 24:00, 48:00, 72:00 hrs But for Frovatriptan the points are 00:00, 00:30, 01:00, 01:50, 02:00, 02:50, 03:00, 03:50, 04:00... hrs Is this not haphazard sampling How is it that the time points are designed in this way — Thanks and Regards, PK |
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manan ☆ Ahmedabad, 2010-12-27 08:04 (5655 d 06:31 ago) @ Phaneendra.K Posting: # 6342 Views: 5,118 |
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Dear Phanni The time points of blood sample colletion are desgined keeping in view the Cmax and the half life of the drug. Now as both this parameters are different for different drugs, the sampling time points also differ. usuaally for a better AUC, the maximum time points are kept around the Cmax of the drug. In your case the Cmax is around 2 - 4 hours. therefore. it is advisable to keep frequent time points in and around 2 aqnd 4 hours to get a better AUC. |
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VRP ☆ India, 2010-12-27 08:09 (5655 d 06:26 ago) @ Phaneendra.K Posting: # 6343 Views: 5,165 |
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Dear Phani, kindly refer to US FDA guidelines on general BA BE guidelines, it cleary mentions that there should be 3-4 time points during the absorption phase, 3-4-5 around the Cmax value and 3-4 during the elimination phase... the details regarding the Cmax and other PK parameters can be searched online. Regards, Dr. Vivek Phirke |
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Helmut ★★★   Vienna, Austria, 2010-12-27 15:43 (5654 d 22:52 ago) @ Phaneendra.K Posting: # 6344 Views: 5,094 |
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Dear Phani! ❝ […] the points are 00:00, 00:30, 01:00, 01:50, 02:00, 02:50, 03:00, 03:50, 04:00... hrs ❝ Is this not haphazard sampling No, only crazy, IMHO. Time intervals in the absorption phase and around Cmax should be evenly spaced and follow a geometric progression in the distribution/elimination phase. What do we have here? 00:30, 00:30, 0:50, 00:10, 00:50, 00:10, 00:50, 00:10… Weird. Are you sure the [hh]:50 is not the result of a copypaste error and should read [hh]:30 instead? Additionally to Manan’s and Vivek’s posts, have a look at this one as well. — Dif-tor heh smusma 🖖🏼 Довге життя Україна! ![[image]](https://static.bebac.at/pics/Blue_and_yellow_ribbon_UA.png) Helmut Schütz ![[image]](https://static.bebac.at/img/CC by.png) The quality of responses received is directly proportional to the quality of the question asked. 🚮 Science Quotes |
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ElMaestro ★★★ Denmark, 2010-12-27 18:29 (5654 d 20:06 ago) @ Helmut Posting: # 6345 Views: 5,064 |
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Hi Phani, ❝ What do we have here? 00:30, 00:30, 0:50, 00:10, 00:50, 00:10, 00:50, 00:10… Weird. Are you sure the [hh]:50 is not the result of a copypaste error and should read [hh]:30 instead? Someone mixed up rendering times in either hours:minutes format or plain decimals and did a little of both. 1h30=1:30=1.5 hours etc. EM. — Pass or fail! ElMaestro |
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Helmut ★★★ Vienna, Austria, 2010-12-27 18:47 (5654 d 19:48 ago) @ ElMaestro Posting: # 6346 Views: 5,060 |
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Dear ElMaestro, though I'm not Phani, clever answer! — Dif-tor heh smusma 🖖🏼 Довге життя Україна! Helmut Schütz The quality of responses received is directly proportional to the quality of the question asked. 🚮 Science Quotes |
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Phaneendra.K ☆ 2010-12-31 15:33 (5650 d 23:02 ago) (edited on 2010-12-31 15:52) @ ElMaestro Posting: # 6362 Views: 4,956 |
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Dear El Mastro, You are right. Edit: Full quote removed. Please delete anything from the text of the original poster which is not necessary in understanding your answer; see also this post! [Ohlbe] — Thanks and Regards, PK |
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pravin17 ★ India, 2010-12-30 08:03 (5652 d 06:32 ago) (edited on 2010-12-30 12:30) @ Phaneendra.K Posting: # 6354 Views: 4,968 |
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Dear Phaneendra.K As per guideline sample collection will cover at least 3 to 5 half lives of drug (i. e. if T1/2 is 10 hrs collection up to 48 hours) and time points depend on Formulation modified release (ER/DR/SR formulations), immediate release. If immediate release; samples should be of 15 min or 20 min and should be around Tmax. Hope this will help you. Pravin Edit: Full quote removed. Please delete anything from the text of the original poster which is not necessary in understanding your answer; see also this post! [Ohlbe] |
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Phaneendra.K ☆ 2010-12-31 15:31 (5650 d 23:04 ago) (edited on 2010-12-31 15:52) @ pravin17 Posting: # 6361 Views: 4,899 |
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Dear Pravin, Can you extend your explanation Thanks and Regards Phani Edit: Full quote removed. Please delete anything from the text of the original poster which is not necessary in understanding your answer; see also this post! [Ohlbe] — Thanks and Regards, PK |
Ing. Helmut Schütz