Chemical study of (+)-(S)-ibuprofen enantiomer chiral inversion by means of chiral TLC separation

Abstract

Ibuprofen is one of the most common nonsteroidal anti-inflammatory and analgesic drugs. It is marked as a racemic mixture though it is known that the pharmacological activity resides in the (+)-(S)-enantiomer only. The process of conversion of (+)-(S)-ibuprofen enantiomer into (−)-(R)-enantiomer, inactive to cyclooxygenase, in methanol and cyclohexane using a chiral selector in TLC separation was investigated. Based on the values of k, t0.1, and t0.5, it is shown that the interconversion of (+)-(S) into (−)-(R)-enantiomer runs 10 times faster in polar methanol than in lipophilic cyclohexane.