(R)-Ibuprofen, a nonsteroidal anti-inflammatory, is the less active enantiomer of ibuprofen. (S)-enantiomer of ibuprofen has the desired therapeutic effect (160 times more active than its (R)-enantiomer) in the in vitro inhibition of prostaglandin synthesis, while the (R)- ibuprofen is inactive. The accumulation of (R)- ibuprofen can cause serious side effects to the human body such as gastrointestinal pain and production of “hybrid” triglycerides between (R)- ibuprofen and Coenzyme A, which disrupt normal lipid metabolism and membrane function. The R(-)-isomer is almost inactive in inhibiting COX-2.