Effervescent and standard formulations of ranitidine--a comparison of their pharmacokinetics and pharmacology.

BACKGROUND

An effervescent formulation of ranitidine may be absorbed faster and achieve a faster onset of action than conventional tablet form. The aim of this study was to compare the effects of effervescent formulations of ranitidine with equivalent dose standard tablets, in terms of intragastric pH and plasma pharmacokinetics in the initial 6 h following dosing.

METHODS

Fifteen fasting healthy males, aged 18-31 (mean 29) years, were each randomly given, at weekly intervals, 150 mg standard and effervescent ranitidine and 300 mg standard and effervescent ranitidine. Ambulatory gastric pH was performed and plasma drug levels measured at regular intervals.

RESULTS

Plasma ranitidine levels increased more rapidly with both effervescent formulations compared with standard tablets as indicated by mean area under curve (AUC) at 1 h (P < 0.001). However, the pH profiles produced by all four treatments were similar with a steep rise in pH at 40-60 min to give a sustained level of pH 7 for the following 5 h. The effervescent formulations produced a transient rise in pH immediately following dosing, and for 300 mg this rise was significantly different at 10-20 min compared with the standard tablet (median pH 4.75 vs. 2.3, P < 0.05).

CONCLUSIONS

Plasma drug levels increase more rapidly following effervescent ranitidine. Effervescent and standard formulations of 150 and 300 mg are all equally effective in producing gastric pH 7 after 1 h. However, effervescent formulations produce an early transient rise in pH which may be of clinical benefit.