Calculation of Drug Concentration

Non-Uniform Multiple Oral Dose Regimen

A patient is started on a drug at an oral dose of 400 mg at time zero, 300 mg at 7 hours and 100 mg at 13 hours (makes no sense but a nice random regimen :- all times are from time zero). Using the data shown in the table below calculate the drug concentration at 24 hr after the first dose time. Assume a one compartment linear model applies to this drug in this concentration range.

Concentration versus Time after a Single 100 mg dose

Time (hr) Concentration (mg/L)

0 0

1 10.7

2 10.1

3 8.44

4 6.91

5 5.65

6 4.62

7 3.77

8 3.08

9 2.52

10 2.06

11 1.68

12 1.37

13 1.12

14 0.918

15 0.75

16 0.613

17 0.501

18 0.409

19 0.334

20 0.273

21 0.223

22 0.182

23 0.149

24 0.122

Concentration versus Time after a Single 100 mg dose
Time (hr)	Concentration (mg/L)
0	0
1	10.7
2	10.1
3	8.44
4	6.91
5	5.65
6	4.62
7	3.77
8	3.08
9	2.52
10	2.06
11	1.68
12	1.37
13	1.12
14	0.918
15	0.75
16	0.613
17	0.501
18	0.409
19	0.334
20	0.273
21	0.223
22	0.182
23	0.149
24	0.122

The equation:

Cp after non uniform multiple dose regimen

Equation 15.4.1 Drug Concentration during a Multiple Dose Regimen (Non-Uniform Regimen)

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