Use of inverse multiple linear regression (ILS) for the analytical controlof pharmaceutical preparations. UV-visible spectrophotometric quantitationof an active principal in the presence of absorbing excipients
M. Blanco et al., Use of inverse multiple linear regression (ILS) for the analytical controlof pharmaceutical preparations. UV-visible spectrophotometric quantitationof an active principal in the presence of absorbing excipients, ANAL LETTER, 32(6), 1999, pp. 1169-1181
The simplicity and robustness of inverse multiple linear regression (ILS) a
s a method for the analytical control of pharmaceutical preparations by W-v
is spectrophotometry is demonstrated. This calibration technique establishe
s a linear relation between the analyte concentration as dependent variable
and absorbance values measured at a small number of wavelengths as indepen
dent variables. In this work, ILS was used to quantify the active principal
in a pharmaceutical preparation commercially available as aqueous solution
.
The preparation was diluted in 40:60 v/v methanol/aqueous 0.1 N NaOH and it
s UV spectrum recorded over the wavelength range 240-330 nm. The calibratio
n equation was derived from laboratory-made solutions of the analyte and ab
sorbing excipients in the preparation. The operating wavelengths used were
those of the absorption maxima for the compounds of interest; the results a
re compared with those obtained by stepwise wavelength selection and high p
erformance liquid chromatography (HPLC).