Nafcillin sodium salt monohydrate

A new degradant of Nafcillin Sodium was found at a level of 1.8% w/w during the gradient reversed-phase HPLC analysis in stability storage samples. This impurity was identified by LC-MS and was characterized by (1)H-NMR, (13)C-NMR, LC/MS/MS, elemental analysis, and IR techniques. Based on the structural elucidation data, this impurity was named as N-[(2S)-2-carboxy-2-{[(2-ethoxynaphthalen-1-yl)carbonyl]amino}ethylidene]-3-({N-[(2-ethoxynaphthalen-1-yl)carbonyl]glycyl}sulfanyl)-D-valine. This impurity was prepared by isolation and was co-injected into the HPLC system to confirm the retention time. To the best of our knowledge, this impurity has not been reported elsewhere. The identification and structural elucidation of this degradant impurity has been discussed in detail.

Nafcillin and oxacillin are used interchangeably in clinical practice, yet few studies have evaluated the safety of these two agents. Our objective was to compare the differential tolerabilities of nafcillin and oxacillin among hospitalized patients. We conducted a retrospective cohort study of all patients who received 12 g/day of nafcillin or oxacillin for at least 24 h. Two hundred twenty-four patients were included. Baseline characteristics and comorbidities were similar among patients receiving nafcillin (n = 160) and those receiving oxacillin (n = 64). Hypokalemia, defined as a potassium level of ≤3.3 mmol/liter or ≤2.9 mmol/liter or as a ≥0.5-mmol/liter decrease from the baseline level, occurred more frequently among patients who received nafcillin (51%, 20%, and 56%, respectively) than among those who received oxacillin (17%, 3%, and 34%, respectively; P < 0.0001, P = 0.0008, and P = 0.005, respectively). By multivariate logistic regression analysis, receipt of nafcillin was an independent predictor of severe hypokalemia (odds ratio [OR] = 6.