Spectroscopic Study of R‐ and S‐Ketoprofen Inclusion Complexes With 2‐Hydroxypropyl‐β‐cyclodextrin

Ketoprofen, also known as (RS)‐2‐(3‐benzoylphenyl)‐propionic acid, has the molecular formula C 16 H 14 O 3 and is classified as a non‐steroidal anti‐inflammatory medication. R‐ketoprofen has stronger analgesic effects than S‐K, and as a result, there is a growing interest in enantio‐recognition research, which may be accomplished through supramolecular interactions, particularly host‐guest reactions. A 1:1 molar ratio was used to produce the combination of separate RK and SK and a 0.01 M stock solution of HP‐β‐CD to get the final concentration of 6 × 10 −4 M. Ethanol was used to make stock solutions of ketoprofen enantiomers (1 mM). Researchers combined a specific volume of ketoprofen with 2‐hydroxypropyl‐beta‐cyclodextrin (HPβ‐CD) and then used spectroscopic methods to study how the S‐ketoprofen (SK) and R‐ketoprofen (RK) enantiomers interact with HPβ‐CD to form inclusion complexes in an aqueous solution. The Benesi–Hildebrand plot was used to determine the inclusion complexes' stoichiometry ratio and binding constant; both enantiomers displayed a 1:1 stoichiometry ratio inclusion complex with HP‐β‐CD. Compared with SK (799 M −1 ), RK has a higher binding constant (1038 M −1 ). These results showed that HP‐β‐CD preferred to form inclusion complexes with RK over SK. At neutral pH, there are significant differences between RK and SK when HP‐β‐CD is present.