Post marketing study of Ponstan®500 mg tablet under suspicion as counterfeit drug at pharmacies

Ponstan® (Mefenamic Acid 500 mg) is one of a few commonly counterfeited drugs in Indonesia. Drug counterfeiting would adversely affect consumers in terms of finances and health. Local health authority rarely conducted market inspection to address such problem. This study was conducted to determine whether Ponstan® sold at pharmacies in the vicinity of public hospital were counterfeit drugs, based on tablets physical characteristics and active substance contents with regards of the Pharmacopeia Indonesia 4^th Edition requirements. This study used Ponstan® sampled from pharmacies within 1 kilometer radius of Class A or B public hospitals in Malang. The packages and tablets were physically inspected, and mefenamic acid assayed by using spectrophotometric method at 285 nm. All of the samples showed similar physical characteristics when compared to the original Ponstan®. Of total 66 tablets collected from 22 pharmacies, mefenamic acid contents were ranging from 94.58% to 111.72% of that listed on their labels, with 3.03% (2/66) contained more than 110%. It can be concluded that 96.97% (64/66) of Ponstan® tablets collected from sampled pharmacies meet the requirements of Pharmacopeia Indonesia 4^th Edition, whereas the other 3.03% belong to “not conformed product” during quality control inspection.