Cloxacillin confirmation

Results showed a total of 2.8% of the samples (n 2972) to be inhibitor positive by the Delvotest SP test further examination identified 1.7% as -lactam antibiotics, and 1.1 % as sulfonamides and dapsone. The percentage of chloramphenicol suspicious samples determined by the Charm II test was amazingly high however, tests for confirmation were not available and contamination of the samples by residues of the chloramphenicol-based preservative azidiol could not be excluded with certainty. Low concentrations of streptomycins were also detected in 5.7% of the samples (n 1221), but the MRL was not exceeded. Macrolide and tetracycline residues were not found in significant levels. Model trials with commercially applied yoghurt cultures confirmed how important the compliance to MRLs can be to dairy industry compared to antibiotic-free milk, a pH of 5.0 was reached with a delay of 15 min in the case of contamination with cloxacillin 30 min in the case of penicillin, spiramycin, and tylosin and 45 min in the case of oxytetracycline contamination. 

The presence of -lactam antibiotics can be confirmed by digestion with Penase, a type I penicillinase, or with a -lactamase (109). In the seven-plate assay, Penase is incorporated in all but one plate to differentiate -lactam antibiotics from other types. However, -lactams such as cloxacillin and the cephalosporins are resistant to degradation by Penase (110-112). Thus, they may not be identified as -lactams by this procedure and are classified as unidentified microbial inhibitors. However, these Penase-resistant compounds can be degraded by other -lactamases. 

Fig. 29.3.2). Under tliese conditions, concentrations as low as 3 ppb for oxacillin and cloxacillin and 4 ppb for penicillin G and penicillin V could be determined in milk using a detection wavelength of 210 nm. Confirmation of the presence of penicillins in the suspected samples was based on the disappearance of the recorded peaks after treatment of the samples with penicillinase and their reanalysis. 

D Hurtaud, B Delepine, P Sanders. Particle-beam liquid chromatography-mass spectrometry method with negative ion chemical ionization for the confirmation of oxacillin, cloxacillin and dicloxacillin residues in bovine muscle. Analyst 119 2731-2736, 1994. 

Canadian data have partly confirmed these findings (169). Benzylpenicillin derivatives and semisynthetic penicillins were applied to 112 patients with a history of an allergic reaction to penicillins. The tests were positive in 21 patients (19%), of whom 10 reacted against the semisynthetic penicillin reagents only. Reports of subjects allergic to flucloxacillin (186), cloxacillin (187), and cefa-droxil (188), but not penicillin, lend further support to the concept of side chain-specific allergic reactions (see the monograph on beta-lactam antibiotics). 

Tyezkowska, K.L. Voyksner, R.D. Straub, R.F. Aronson, A.L. Simultaneous multiresidue anMysis of 3-lactam antibiotics in bovine milk by liquid chromatography with ultraviolet detection and confirmation by electrospray mass spectrometry. J.AOAC Int., 1994, 77, 1122-1131 [cow milk LC-MS UV detection LOD 10 ppb column temp 40 extracted amoxicillin, ceftiofur, cephapirin, cloxacillin, penicillin G]... 

Rana et al prepared P(2-EHA)-silicate nanocomposites by batch emulsion polymerization of 2-EHA in the presence of sorbitol, using potassium persulfate as initiator. The nanocomposites so prepared were shown to be intercalated by XRD, TEM and IR spectroscopy. However, according to the authors," the nanocomposite failed to satisfy the desired application in transdermal drug delivery. Consequently, they improved their product by preparing a P(2-EHA-cu-AA)-silieate nanocomposite. AA was chosen for its polarity and known bioadhesive properties and 2-EHA for its hydrophobicity and softness. Copolymers with different molar ratios of the monomers were prepared. Sorbitol was used as emulsifier and benzoyl peroxide as initiator therefore, the synthesis process" may be classified as suspension copolymerization. The drug cloxacillin sodium was added to the reaction mixture after 2 h of polymerization and 1 h before the reaction was terminated. The nanocomposites so prepared were shown to be intercalated by XRD and TEM. NMR and IR spectroscopy confirmed the copolymer formation and the absence of monomer impurities in the product. 

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