Effect of Zobo drink (Hibiscus sabdariffa water extract) on the pharmacokinetics of acetaminophen in human volunteers

Acetaminophen, a common antipyretic-analgesic OTC drug is often administered orally anytime of the day with water or beverages irrespective of possible interactions. Zobo drink, is a sweetened water extract of the dried calyx of Hibiscus Sabdariffa. This work is designed to investigate the effect of zobo drink on an oral dose of acetaminophen. Six healthy male volunteers, ages 28.50+/-1.76 years, weighing 62.67+/-1.67kg participated in the study. The study was carried out in two phases. In the first phases an oral dose of acetaminophen (1g) was administered to the volunteers and in the second phases, zobo drink was ingested by the volunteers 1.30 h prior the administration of acetaminophen (1g). Acetaminophen concentration in plasma was determined using a validated spectrophotometric method. Pharmacokinetic values obtained were found to be in similar ranges as those previously reported. The absorption parameters t(1/2a), Ka, T-max, C-max and AUC(o-alpha) showed no statistically significant changes (p>0.05) after the administration of zobo. There were however statistically significant changes (p<0.05) in K-β and t(1/2β) of acetaminophen when administered after the zobo drink. This also resulted in 11.69% increase in Cl-T.