Synthesis and spectrophotometric study of omeprazole charge transfer complexes with bromothymol blue, methyl orange and picric acid

Spectrophotometric determination of omeprazole through charge transfer complex has been described using bromothymol blue, methyl orange and picric acid. Formed complexes were investigated at 400, 420 and 373 nm in the concentration ranges of 7-56, 6-48 and 10-80 µg mL-1 respectively. The apparent molar absorptivity values have been determined. The data is discussed in terms of oscillator’s strength, dipole moment, ionization potential, energy of complexes, resonance energy, association constant and Gibb’s free energy changes. Benesi-Hildebrand plots have been constructed. Applicability of method was demonstrated by determining the omeprazole in pharmaceutical formulations which showed good percent recovery values. Commonly present excipients did not interfere during analysis. Solid charge transfer complexes were synthesized and characterized by IR and 1H NMR spectroscopy.