薬理と治療

Abstract

Objectives To evaluate the safety of an oyster extract︱based, tablet︱form dietary supplement “Watanabe Active Oyster Tablet”（WAOT）. Methods With the use of a commercial product of WAOT containing 250 mg of oyster extract per tablet as the study diet, two clinical studies were performed in a total of 47 healthy male and female adults. In the first study designed as an excessive dosing study（StudyⅠ）, 12 subjects each received a regular dose（6 tablets）, 3-fold increased dose（18 tablets）, and 5-fold increased dose（30 tablets）daily for 4 weeks with a 2-week follow-up period. In the second study designed as a long-term dosing study （StudyⅡ）, 11 subjects received 12 tablets of the study diet for 12 weeks. Medical inspection and laboratory tests were conducted at week 4 of the intervention period and at week 2 of the follow-up period in the StudyⅠ and at weeks 4, 8and 12 of the intervention period in the StudyⅡ. Results Throughout these two studies, there was no subject who had any intervention-related laboratory abnormalities. In the StudyⅠ, while most of self-reported adverse events were unrelated to intervention, a possible relationship of a total of 11 mild and transient diarrhea events experienced by 3, 2, and 3 subjects in the regular dose, 3-fold increased dose and 5-fold increased dose groups, respectively, were unable to be ruled out. Different from this none of subjects reported diarrhea event in the StudyⅡ. The results of study group-based analyses showed that there were no clinically significant changes from baseline of any demographic, physical or laboratory test parameters in the two studies. Conclusion Intakes of WAOT in daily doses up to 30 tablets（7500 mg as oyster extract）for 4 weeks and those in a daily dose of 12 tablets（3000 mg as oyster extract）for up to 12 weeks were considered to be well tolerable and safe in healthy adults.