Abstract The development of UV and fluorescence spectrophotometric methods for the quantitative
determination of alprazolam in dosage forms using As(III)SDS system. The two simple and
sensitive, spectrophotometric and spectrofluorimetric methods were developed for the determination
of alprazolam (ALP) in tablets. These methods are based on formation of ALPAs(III) complex
in the presence of SDS. The UV-spectrum of 30% methanolic solution of ALP (5 · 105 M) at
pH 6.5 (Mclivaine buffer) was run between 200 and 380 nm. The absorption spectrum of ALP
exhibits two peaks with a kmax. at 255 nm and a weak band at 325 nm. When the spectra of the drug
were run at varying pH in the region 200–380 nm, one isosbestic point at 290 nm was observed,
which indicated the presence of two ionic conditions in solution. The complex exhibited an absorption
maximum at 265 nm and emission peak at 520 nm with respect to the excitation wavelength of
325 nm. The spectrophotometric method was found to be linear in 8.0–17.0 lg ml1 range with
detection limit of 13.520 lg ml1
, while 0.05–9.5 lg ml1 range was with detection limit of
1.048 · 102 lg ml1 by spectrofluorimetric method. The mean percentage recovery of the added
quantity was found to be 99.54 (spectrophotometric method) and 100.22 (spectrofluorimetric
method) and the %RSD are lower than 0.478 and 0.296 determined spectrophotomerically and
spectrofluorimtrically, respectively. This indicates that the proposed method is accurate. The apparent
ionization constant of ALP was found to be 9.29. The spectra, experimental conditions were set
followed by determination stoichiometry, stability constant and thermodynamic parameters of the
As(III), Co(II), Ni(II), and Zn(II) complexes with ALP at pH 6.5. The proposed methods have been
successfully applied to the assay of ALP in tablets and the results were statistically evaluated.
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