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Ankit Parikh ☆  India, 2023-06-08 15:54 (551 d 22:02 ago) Posting: # 23582 Views: 2,990 |
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How to calculate within subject standard deviation in fully replicate study design of carry over effect is present? Eg. I am planning a full replicate single dose study in patients. Patients has to take medication at every 4 month. Pre-dose concentration in subsequent periods are observed below 5 % of Cmax or 0 in pilot study. If carryover effect is present in pivotal study but the pre-dose concentration is less than 5 % of Cmax, how should I calculate Swr for BE assessment? After dosing, the plasma concentration reaches Cmax in about 4 hours and comes down below 5 % of Cmax in 2-3 days and remains stable from day 4 to 120 and is also the pre-dose concentration for subsequent period/s. The primary PK parameters are Cmax, AUC0-t and AUC7-t Thank you for your response in advance. Edit: Category changed; see also this post #1. [Helmut] |
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dshah ★★ India, 2023-06-08 18:35 (551 d 19:21 ago) @ Ankit Parikh Posting: # 23583 Views: 2,421 |
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Hello Ankit! ❝ After dosing, the plasma concentration reaches Cmax in about 4 hours and comes down below 5 % of Cmax in 2-3 days and remains stable from day 4 to 120 and is also the pre-dose concentration for subsequent period/s. I am not getting you. By 2-3 days, the concentration are below 5% of Cmax and then stable from day 4 to 120? So by 2-3 days, almost all the drug is eliminated? What is the average half life and range of half life for drug? Regards, Divyen |
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Ankit Parikh ☆ India, 2023-06-09 09:15 (551 d 04:42 ago) @ dshah Posting: # 23584 Views: 2,311 |
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Hello Divyen! After dosing, the plasma concentration reaches Cmax in about 4 hours and comes down below 5 % of Cmax in 2-3 days and remains stable from day 4 to 120 and is also the pre-dose concentration for subsequent period/s. ❝ I am not getting you. By 2-3 days, the concentration are below 5% of Cmax and then stable from day 4 to 120? ❝ So by 2-3 days, almost all the drug is eliminated? What is the average half life and range of half life for drug? Cmax is due to the burst phase of release from the formulation however the plasma concentration required to produce therapeutic effect is very low i.e. < 5 % of Cmax and it remains in therapeutic range from Day 4 to 120 due to slow release of the product. It provides therapeutic effect for 4 months and then new injection has to be taken on day 120. Regards Ankit |
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dshah ★★ India, 2023-06-14 11:26 (546 d 02:31 ago) @ Ankit Parikh Posting: # 23588 Views: 2,176 |
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Hello Ankit! ❝ Cmax is due to the burst phase of release from the formulation however the plasma concentration required to produce therapeutic effect is very low i.e. < 5 % of Cmax and it remains in therapeutic range from Day 4 to 120 due to slow release of the product. It provides therapeutic effect for 4 months and then new injection has to be taken on day 120. If by day 4- conc. are LT 5% of Cmax- then what is your half life? Why do you want to measure it for 120 days and the burst release doesn't have any toxicity impact? If even product name can not be shared- then it is difficult to be answered from very few details. Regards, Divyen |
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Ankit Parikh ☆ India, 2023-06-14 11:33 (546 d 02:24 ago) @ dshah Posting: # 23589 Views: 2,182 |
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Hello Divyen! ❝ ❝ Cmax is due to the burst phase of release from the formulation however the plasma concentration required to produce therapeutic effect is very low i.e. < 5 % of Cmax and it remains in therapeutic range from Day 4 to 120 due to slow release of the product. It provides therapeutic effect for 4 months and then new injection has to be taken on day 120. ❝ This seems to be LAI and from initial post also a HVD? Yes it is LAI. ❝ If by day 4- conc. are LT 5% of Cmax- then what is your half life? Why do you want to measure it for 120 days and the burst release doesn't have any toxicity impact? If even product name can not be shared- then it is difficult to be answered from very few details. So how to calculate Swr when unequal carryover effect is present in full replicate study design? Regads Ankit |
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dshah ★★ India, 2023-06-14 12:37 (546 d 01:20 ago) @ Ankit Parikh Posting: # 23591 Views: 2,186 |
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Hello Ankit! As per PSG, the recommendation is parallel study. ![[image]](img/uploaded/image246.jpg) ❝ So how to calculate Swr when unequal carryover effect is present in full replicate study design? Moreover, the study population is patient and you can not stop the treatment. So why fully replicate CO study? Regards, Divyen |
Ing. Helmut Schütz