Multiple dose comparison of a whole 240 mg verapamil sustained-release tablet with two half tablets.
Twelve healthy male volunteers were studied in a balanced crossover comparison of an intact 240 mg verapamil sustained-release tablet (Securon SR, Isoptin Forte Retard) given once daily for 7 days, and the same dose given as two half tablets. One subject was withdrawn because of asymptomatic second degree heart block on day 3 of verapamil treatment. The mean Cmax after dosing with whole tablets, 143 (95 per cent confidence limits 91.6-223) ng ml-1 was lower than after dosing with half tablets, 160 (107-241) ng ml-1, but this was not significant (p = 0.49). The mean steady-state Cmin values after whole and half tablets were also similar: 22.2 (12.6-39.4) ng ml-1 and 22.0 (16.2-29.9) ng ml-1, respectively (p = 0.96). The mean (+/- S.D.) tmax, AUC0-24 and t 1/2 were not significantly different: whole tablet 3.5 +/- 1.2 h, 1733 +/- 1125 ng.h ml-1 and 10.5 +/- 3.4 h, respectively, and half tablets 3.6 +/- 1.0 h, 1780 +/- 1057 ng.h ml-1 and 9.6 +/- 2.3 h, respectively. The findings for plasma norverapamil were generally similar to those for the parent drug. This investigation indicates that the formulation is sufficiently robust to retain its sustained-release properties when the tablet is halved.
Moreland
T A
TA
Drug Development (Scotland) Limited, Ninewells Hospital, Dundee.
McMurdo
M E
ME
McEwen
J
J
D000328:Adult; D003692:Delayed-Action Preparations; D004562:Electrocardiography; D006801:Humans; D008297:Male; D013607:Tablets; D014700:Verapamil / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology
D003692:Delayed-Action Preparations; D013607:Tablets; C016904:norverapamil; D014700:Verapamil