Finger pulse plethysmographic effects of two oral sustained-release formulations of isosorbide dinitrate in normal man

Two sustained release formulations of 40 mg isosorbide dinitrate, encapsulated pellets and a tablet, were compared double blind following oral administration of single doses in terms of response on finger pulse plethysmography in nine healthy male volunteers. Following both formulations there was a distinct effect on the depth of b-wave in the first derivative of the finger pulse up to 9 h after administration. This change of the parameter of nitrate action was significantly different from placebo for both formulations. The onset of action was more rapid and the peak response greater for the capsule than for the tablet. The overall effects in terms of area under the effect-time curves was also greater for the capsule than for the tablet, however, not statistically significant. Furthermore, the results show that the method of finger pulse plethysmography can be used to determine onset and duration of action of nitrate compounds, after single dose administrations.