Gliclazide charge transfer complexes with some benzoquinone acceptors: Synthesis, structural characterization, thermal analyses, DFT studies, evaluation of anticancer activity and utility for determination of gliclazide in pure and dosage forms

•The CT complexes of gliclazide with DDQ and PCA were of 1:1 stoichiometric ratio.•DDQ and PCA were used successfully to determine GLZ in diamicron and diamedizen tablets.•GLZ underwent CT complexation as a n-donor drug.•DFT and TD-DFT calculations were carried out for the formed complexes.•The CT complexes were screened for their anticancer activity against breast cancer cell line.