Dicloxacillin analysis

Currently, the most commonly used method for determining drug impurities is HPLC-MS. Such analysis requires proper preparation of the sample, adequate adjustment of separation parameters, and use of an ionization method. The use of soft ionization produces the molecular ion of the impurity and enables its molecular weight to be established. Use of tandem MS/MS spectrometry allows the chemical structure of the impurity to be established by marking its fragmentation schemes. Liquid chromatography coupled with MS detection was used in purity studies of zaleplon [63], etoricoxib [64], ethanediol, diacetate [65], dicloxacillin [66], quinapril [67], and others described in several review articles [68-70]. 

BenzylpenicUlin (PCG), phenoxymethylpeniciUin (PCV), oxacillin (MPIPC), cloxaciUin (MCIPC), nafcillin (NFPC), and dicloxacillin (MDIPC), aU of which are representative weakly acidic penicUlins, are widely used as veterinary drugs for livestock. We have reported, in our previous studies, the applicability of sample cleanup with an ion-exchange cartridge, in combination with ion-pair HPLC, for the analysis of ionizable compounds. We therefore applied the same technique to develop an analytical method for the quantitative determination of these residual penicillins in bovine muscle, kidney, and liver. ... 

Ito, Y. Ikai, Y. Oka, H. Matsumoto, H. Kagami, T. Takeha, K. Application of ion-exchange cartridge clean-up in food analysis, in. Determination of henzylpenicillin, phenox3methylpenicilhn, oxacillin, cloxacillin, nafcillin, and dicloxacillin in hovine hver and kidney hy liquid chromatography with ultraviolet detection. J. Chromatogr., A 2000, 880, 85-91. 

Parker, C.E. Perkins, J.R. Tomer, K.B. Shida, Y. O Heu-a, K. Nanoscale packed capillary liquid chromatography-electrospray ionization mass spectrometry analysis of penicillins and cephems. J.Chromatogr., 1993, 616, 45-57 [capillary HPLC electrospray LC-MS serum also ampiciUin, car-benicUlin, cefalothin, cefazoUn, cefmenoxime, cefmetetzole, cefoperazone, cefotaxime, cefotiam, cefoxitin, cephalexin, cloxacillin, dicloxacillin, peniciUin G, pipericillin, sulbenicillin]... 

In visible spetrophotometric analysis of penam and cephem analogs, their ability to form ion-pair was also used. The penam analogs contacting the tertiary amine group (ampicillin, dicloxacillin, flucloxacillin, amoxicillin) and Mo(V)-thiocyanate binary complex in hydrochloric acid give coloured ion-pair formation absorbing at X = 467 nm (Fig. 14) [48]. 

Fig. 2 ESI LC/MS/MS analysis of penidUins fortified at a concentration of 0.05 mg/kg in bovine liver, a. Mass chromatograms monitored at [M-H-141] b, tandem mass spectra of penicillins recorded at the top of each peak on the mass chromatograms (a), (h-1) BenzylpeniciUin (b-2) phenoxymethylpeniciUin (b-3) oxacillin (b-4) cloxacillin (b-5) nafcUlin (b-6) dicloxacillin.

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