Bioanalytical Method Development of Atenolol Enantiomers: Stereoselective Behavior in Rabbit Plasma by RP-UFLC Method

Objective: The objective of the method was to develop a new, simple and reliable enantioselective Reverse Phase- Ultra-Fast Liquid Chromatography (RP-UFLC) method for the separation of Atenolol enantiomers. A comprehensive study was performed by extending the work to pharmacokinetic studies using rabbit plasma. Background: Many methods were reported for enantioseparation of Atenolol enantiomers but no attempts were made for chiral separation of Atenolol using rabbit plasma. Moreover, pharmacokinetic data to prove the efficiency of particular enantiomers in rabbit plasma was not studied. Methods: In the present examination, the binary RP-UFLC technique was developed on Phenomenex® Lux cellulose i5 segment (150×4.6 mm, 5μ) using di-sodium hydrogen phosphate buffer (pH 6.8): acetonitrile (35:65 v/v) as the mobile phase. Results: The elution of Atenolol was observed at 225 nm with a stream rate of 1 mL.min^-1. The described technique offered a linear relationship with a regression coefficient of r² = 0.997 and 0.996 for (R) and (S)-enantiomer respectively, between the concentration range of 2-10 ng.mL^-1. Atenolol enantiomers were detected at a retention time (tR) of 2.7 min and 3.10 min for R and S-enantiomer respectively. The rate of recovery of both Atenolol enantiomers was observed to be (R) 98.18% and (S) 100.45% individually. USFDA guidelines May 2018 were systematically followed for the development and validation of the bioanalytical method. Conclusion: The developed technique was applied for the separation of Atenolol enantiomers and for the pharmacokinetic determination of Atenolol enantiomers in rabbit plasma.