Potassium acid tartrate
Potassium bitartate, also referred to as potassium acid tartrate or cream of tartar, is the potassium acid salt of l-( + )-tartaric acid. It is obtained as a byproduct of wine manufacture during the fermentation process. Approved by the FDA as a direct food substance, potassium bitartrate is used as an additive, stabilizer, pH control agent, antimicrobial agent, processing aid, or thickener in various food products. Potassium bitartrate has a long history of medical use as a laxative administered as a rectal suppository and is an approved third-class OTC drug in Japan.  Potassium bitartrate was one of active ingredients in Phexxi, a non-hormonal contraceptive agent that was approved by the FDA on May 2020.