ENANTIOMERIC DETERMINATION OF HIGHLY OVERLAPPED CHROMATOGRAPHIC PROFILES WITH PRESENCE OF AN INTERFERENT. APPLICATION TO THE ENANTIOMERIC COMPOSITION DETERMINATION OF IBUPROFEN IN PRESENCE OF HOMATROPINE AS INTERFERENT

OSORIO GRISALES, J.; ARANCIBIA, J.; CASTELLS, C.; OLIVIERI, A. C.

Florianópolis

Congreso; XIV Congreso Latinoamericano de Cromatografía; 2012

COLACRO

The development of a chiral chromatographic method often requires expensive and timeconsuming testing of different columns and chromatographic conditions. Also, for checking enantiomeric purity, the enantiomer of interest (minor peak) has to be usually quantitatively analyzed at levels down to 1% of the main enantiomer. This requires injecting large amounts of sample to increase sensitivity for the minor peak; the other component may become broader and tailed as a result of mass overload. Thus, higher accuracy in detection and quantitation of a minor signal close to the major peak in the chromatogram can be obtained as larger the enantioresolution is, being the aim to get truly baseline separated these very unequal profiles. However, the most usual scenario, especially in reversed-phase HPLC, is to hardly get baseline resolution and it is very often observed a partial overlapping between both enantiomer profiles, causing loss in the quantitation accuracy. Besides, the possible presence of another component in the sample that coelutes with the interest signals makes the problem even worse. Fortunately, when second-order data are recorded, for instance by using a diode-array detector (DAD) coupled to the HPLC, this enable the use of chemometric tools like partial least-squares (PLS) that permits analyte quantitation of even overlapped peaks in multicomponents samples [1–4]. Homatropine and ibuprofen are commonly prescribe together to treat muscle spasm and pain relief. Also, ibuprofen is sometimes commercialized as S-(+)-ibuprofen, in this case R-(-)-ibuprofen is considered an impurity. Chiral reversed phase HPLC, using a permethyl- β-cyclodextrin column and isocratic mobile phase conditions, was used to run the samples. Ibuprofen peaks were partially overlapped and homatropine coeluted with them. In this work, we obtained quantitative and accurate information about enantiomeric purity even in presence of the homatropine interferent and with highly overlapped peaks, by using indirect calibration of the peaks by chemometrics tools. [1] K.S. Booksh, B.R. Kowalski, Analytical chemistry, 66 (1994) 782A–791A.[2] H.C. Goicoechea, M.J. Culzoni, M.D.G. García, M.M. Galera, Talanta, 83 (2011) 1098–107.[3] J.O. Grisales, J.A. Arancibia, C.B. Castells, A.C. Olivieri, Journal of Chromatography B, (2012).), in press.[4] L. Vera-Candioti, M.J. Culzoni, A.C. Olivieri, H.C. Goicoechea, Electrophoresis, 29(2008) 4527–4537.Agradecimentos: CONICET, Instituto de química de Rosario (IQUIR) and Universidadnacional de La Plata (UNLP).