Orocecal transit time in humans assessed by sulfapyridine appearance in saliva after sulfasalazine intake.

PURPOSE: We propose a noninvasive method for the measurement of orocecal transit time assessed by the sulfapyridine appearance time in saliva after ingestion of sulfasalazine. METHOD: In 12 healthy volunteers, we studied the correlation between plasma and saliva sulfapyridine appearance times and then the sulfapyridine appearance times in saliva under various experimental conditions to assess the reproducibility, the effects of meals, and the role of the formulation, and the effects of gastrointestinal kinetic drugs. RESULTS: The correlation between saliva and plasma sulfapyridine appearance times was strong (r = 0.84; p = 0.0004). The sulfapyridine saliva appearance time was significantly delayed by the meal. Compared with placebo, the saliva sulfapyridine appearance time was reduced by cisapride (312 +/- 128 versus 551 +/- 97 minutes; p = 0.0001) and increased by loperamide (674 +/- 267 versus 501 +/- 131 minutes; p = 0.044). CONCLUSION: We propose the salivary sample method as a validated simplification of the plasma sulfasalazine-sulfapyridine test for the measurement of orocecal transit time.