Enantioselective separation and determination of adrafinil and modafinil on Chiralcel OJ-H column in rat serum and urine using solid-phase extraction followed by HPLC.
A simple and rapid normal-phase HPLC method for enantiospecific separation of a psychostimulant, adrafinil (ADL), and its metabolite modafinil (MDL) in rat serum and urine was developed. The separation was accomplished on a normal-phase polysaccharide stationary phase Chiralcel OJ-H using n-hexane-ethanol (62:38 v/v) as a mobile phase at a flow rate of 1.0 mL/min. Detection was carried out at 225 nm using a photo diode array (PDA) detector. The elution order of the enantiomers was determined by a polarimeter connected in series with the PDA. ADL and its metabolite were recovered from rat serum and urine by solid phase extraction using Oasis HLB cartridges and the mean recoveries were >or=80%. The enantiomers were eluted within 15 min without any interference from endogenous substances. The calibration curves were linear (r(2) > 0.998) in the concentration range of 1.20-500 microg/mL for ADL and MDL. The assay was specific, accurate, precise and reproducible (intra- and inter-day precisions RSDs <7.2%). ADL in rat serum was stable over three freeze-thaw cycles at ambient temperature for 4 h. The method was successfully applied to pharmacokinetic studies of adrafinil after an oral administration to rats.
Analytical Chemistry Division, Discovery Laboratory, Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India. rnrao55@yahoo.com
R Nageswara
RN
Rao
Dhananjay D
DD
Shinde
D000818:Animals; D001559:Benzhydryl Compounds / Q000097:blood* / Q000652:urine*; D002138:Calibration; D000697:Central Nervous System Stimulants / Q000097:blood* / Q000652:urine*; D002851:Chromatography, High Pressure Liquid / Q000191:economics / Q000379:methods*; D000431:Ethanol; D006586:Hexanes; D006877:Hydroxamic Acids / Q000097:blood* / Q000493:pharmacokinetics / Q000652:urine*; D016014:Linear Models; D000077408:Modafinil; D051381:Rats; D017208:Rats, Wistar; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction / Q000191:economics / Q000295:instrumentation / Q000379:methods*; D013237:Stereoisomerism; D013997:Time Factors
D001559:Benzhydryl Compounds; D000697:Central Nervous System Stimulants; D006586:Hexanes; D006877:Hydroxamic Acids; C026385:n-hexane; D000431:Ethanol; C022116:adrafinil; D000077408:Modafinil