Novel voltammetric method for enantioseparation of racemic methotrexate: Determination of its enantiomeric purity in some pharmaceuticals

摘要: Abstract A carbon paste electrode is modified by hydrophobic molecules of hydroxypropyl β-cyclodextrin to form enantioselective membrane sensor. In neutral aqueous media, methotrexate (Mtx) enantiomers have been selectively accumulated at this sensor depending on their hydrophilic/hydrophobic balance and then they can be quantified voltammetric oxidation. The effect solution instrumental parameters rac -Mtx enantioresolution investigated using window diagram approach. optimal ( R  = 2.96) achieved pH 6.4 in phosphate buffer applying osteryoung square-wave anodic stripping voltammetry. obtained resolution sufficient evaluate distomer d 0.1% (m/m l -Mtx, the main compound). Selectivity proposed procedure estimated testing recovery adding most interfering metal ions and/or organic compounds. satisfactorily used investigate simultaneously ssDNA interactions with -Mtx. It observed that stability -Mtx-ssDNA diasteriomeric complexation higher than -Mtx-ssDNA. These results are crucial medical chemistry for investigating many phenomena concerned carcinogenic methotrexate. Using commercially available certified reference materials approach validated determine Mtx enantiopurity its tablets injections values falling within labeled amount 90–110% R.S.D. less 6.00% required US Pharmacopeia. Furthermore, high accuracy application method formulations statistically confirmed calculating F -test t 95% confidence level.