Xanthine derivatives quantification in serum by capillary zone electrophoresis.
A capillary electrophoresis method was developed to quantify caffeine and theophylline, xanthine derivatives with bronchodilator activity. Buffer concentration, pH and applied voltage were optimized using a central composite design-face centred. Separation conditions were: silica capillary tube, 75 μm (i.d.) and 61 cm (total length); absorbance detection, 280 nm; borate buffer, 20 mM, pH 9.0; applied voltage, 25 kV and 1 psi injection/8 s. Validation was performed in blank serum following the International Conference Harmonization guidelines: resolution (peaks without overlapping), linear range (0.125-50 µg/mL; r(2) > 0.9999), limits of detection and quantification (10; 20 and 33; 66 ppb for caffeine and theophylline, respectively), intra- and inter-day precision (Relative standard deviation lower than 1.9%) and accuracy (98-101%). Migration times were <8 min. This method is simple, specific and suitable and reaches high label claims (98.7-100.4%) in pharmaceutical formulations analysis. Moreover, the method was applied to the monitoring of the analytes in serum of patients.
Química Bioanalítica, Q.F.A., E.S.T.C.E., Universitat Jaume I, 12071-Castelló, Comumitat Valenciana, Spain vicentej@qfa.uji.es.
Juan
J
Peris-Vicente
Química Bioanalítica, Q.F.A., E.S.T.C.E., Universitat Jaume I, 12071-Castelló, Comumitat Valenciana, Spain.
Maria
M
Rambla-Alegre
Department of Applied Chemistry, Banaras Hindu University, Vanarasi 221005, Uttar Pradesh, India.
Abhilasha
A
Durgavanshi
Criminology and Forensic Sciences, Dr H.S. Gour University, Sagar 470003, Madhya Pradesh, India.
Devasish
D
Bose
Química Bioanalítica, Q.F.A., E.S.T.C.E., Universitat Jaume I, 12071-Castelló, Comumitat Valenciana, Spain.
Josep
J
Esteve-Romero
Química Bioanalítica, Q.F.A., E.S.T.C.E., Universitat Jaume I, 12071-Castelló, Comumitat Valenciana, Spain.
Sergio
S
Marco-Peiró
D002021:Buffers; D002110:Caffeine / Q000097:blood; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013806:Theophylline / Q000097:blood; D014970:Xanthines / Q000097:blood*
D002021:Buffers; D014970:Xanthines; D002110:Caffeine; D013806:Theophylline