Table 1.

Mean pharmacokinetic parameters of quinine and its major metabolite (3-hydroxyquinine) following administration of 600 mg single oral doses of quinine sulphate alone or with multiple doses of ritonavir (200 mg 12 hourly for 9 days) to each of 10 healthy volunteers

Pharmacokinetic parameter	Quinine alone	Quinine with ritonavir	Mean difference (95% confidence interval of mean difference)
Quinine	3.20 (2–4)	3.40 (2–4)	0.2 (−0.25, 0.65)
Tmax (h)	2.79 ± 0.22	10.72 ± 0.32	7.92 (7.81, 8.04)*
Cmax(mg l−1)	11.15 ± 0.80	13.32 ± 0.33	2.21 (1.64, 2.77)*
T1/2β (h)	50.06 ± 4.01	220.47 ± 6.68	170.78 (166.3, 175.3)*
AUCT(mg h−1 l−1)	12.01 ± 0.61	2.71 ± 0.10	−9.30 (−9.71, −8.89)*
CL/F (l h−1)	8.80 (8–12)	9.20 (8–12)	0.40 (−0.51, 1.31)
3-hydroxyquinine	1.80 ± 0.12	0.96 ± 0.09	−0.84 (−0.94, −0.73)*
Tmax (h)	62.80 ± 6.30	25.61 ± 2.44	−37.49 (−42.12, −32.83)*
Cmax (mg l−1)	1.35 ± 0.10	0.13 ± 1.01	−1.22 (−1.34, −1.11)*
AUC0–48h (mg h−1 l−1)
MR

^*Statistically significant (P < 0.01); the pharmacokinetic parameters are as described in the text. Quinine was co-administered with the 15th dose (day 8) of ritonavir. MR, metabolic ratio.