Calculation of Drug Concentration

Non-Uniform Multiple Oral Dose Regimen

A patient is started on a drug at an oral dose of 250 mg at time zero, 50 mg at 3 hours and 150 mg at 7 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 3.36

2 2.94

3 2.22

4 1.64

5 1.2

6 0.878

7 0.643

8 0.471

9 0.345

10 0.252

11 0.185

12 0.135

13 0.0989

14 0.0724

15 0.053

16 0.0388

17 0.0284

18 0.0208

19 0.0152

20 0.0111

21 0.00815

22 0.00597

23 0.00437

24 0.0032

Concentration versus Time after a Single 100 mg dose
Time (hr)	Concentration (mg/L)
0	0
1	3.36
2	2.94
3	2.22
4	1.64
5	1.2
6	0.878
7	0.643
8	0.471
9	0.345
10	0.252
11	0.185
12	0.135
13	0.0989
14	0.0724
15	0.053
16	0.0388
17	0.0284
18	0.0208
19	0.0152
20	0.0111
21	0.00815
22	0.00597
23	0.00437
24	0.0032

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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