An experience with the colorimetric testing of amlodipine in physiological fluids: interference in drug assay by phytochemicals

Abstract

This study aims to examine the possible interactions between amlodipine (AML) and methanol extract of
Aframomum melegueta seeds (AMSE). Methods: Using the potassium ferricyanide/FeCl3 (FeCl3/K4(Fe(CN)6))
technique, amlodipine concentrations of 2.5, 5.0, 7.5, 10, 12.5 and 15 μg/mL were tested in vitro with or without
AMSE. Absorbance measurements were taken at 393.1, 455.6, and 774.8 nm, and the solution was then subjected
to wavelength scanning in the 380–950 nm range. Conclusions: The presence of Aframomum melegueta seeds
(AMSE) in biological fluids and AML solutions considerably hindered the reaction of FeCl3/K4(Fe(CN))6. The
maximum interference was seen at 774.8 nm, and a concentration of 50 μg/mL AMSE resulted in a 2.5 μg/mL rise
in absorbance, which is 1.5 times higher than when it was not present. The sample's spectra showed two extra
peaks at 393.1 and 455.6 nm, with unit increments of just 0.07 and 0.16 nm, respectively, when AMSE was present.
At these two wavelengths, Beer-Lambert's law was met by the concentration-absorption relationship. It was decided
not to follow Beer-Lambert's rule after the AML concentration reached 15 μg/mL at 774.8 nm. This research
concludes that the components of the Aframomum melegueta seed methanol extract may interact with one another
in AML testing techniques. In addition, measurements of concentration at either 393.1 or 455.6 nm have been
shown to be reliable. When measuring drugs in populations where the use of herbal treatments is likely to occur
concurrently, this should be taken into consideration. Amlodipine, Aframomum melegueta, Colorimetry,
Interference