DESCRIPTION

Cefuroxime is a semisynthetic, broad-spectrum, cephalosporin antibiotic for parenteral administration. It is the sodium salt of (6R,7R)-3-carbamoyloxymethyl-7-[Z-2-methoxyimino-2-(fur-2-yl)acetamido]ceph-3-em-4-carboxylate, and it has the following chemical structure:

The empirical formula is C16H15N4NaO8S, representing a molecular weight of 446.4.

ZINACEF contains approximately 54.2 mg (2.4 mEq) of sodium per gram of cefuroxime activity.

ZINACEF in sterile crystalline form is supplied in vials equivalent to 750 mg, 1.5 g, or 7.5 g of cefuroxime as cefuroxime sodium and in ADD-Vantage® vials equivalent to 750 mg or 1.5 g of cefuroxime as cefuroxime sodium. Solutions of ZINACEF range in color from light yellow to amber, depending on the concentration and diluent used. The pH of freshly constituted solutions usually ranges from 6 to 8.5.

ZINACEF is available as a frozen, iso-osmotic, sterile, nonpyrogenic solution with 750 mg or 1.5 g of cefuroxime as cefuroxime sodium. Approximately 1.4 g of Dextrose Hydrous, USP has been added to the 750-mg dose to adjust the osmolality. Sodium Citrate Hydrous, USP has been added as a buffer (300 mg and 600 mg to the 750-mg and 1.5-g doses, respectively). ZINACEF contains approximately 111 mg (4.8 mEq) and 222 mg (9.7 mEq) of sodium in the 750-mg and 1.5-g doses, respectively. The pH has been adjusted with hydrochloric acid and may have been adjusted with sodium hydroxide. Solutions of premixed ZINACEF range in color from light yellow to amber. The solution is intended for intravenous (IV) use after thawing to room temperature. The osmolality of the solution is approximately 300 mOsmol/kg, and the pH of thawed solutions ranges from 5 to 7.5.

The plastic container for the frozen solution is fabricated from a specially designed multilayer plastic, PL 2040. Solutions are in contact with the polyethylene layer of this container and can leach out certain chemical components of the plastic in very small amounts within the expiration period. The suitability of the plastic has been confirmed in tests in animals according to USP biological tests for plastic containers as well as by tissue culture toxicity studies.

CLINICAL PHARMACOLOGY

After intramuscular (IM) injection of a 750-mg dose of cefuroxime to normal volunteers, the mean peak serum concentration was 27 mcg/mL. The peak occurred at approximately 45 minutes (range, 15 to 60 minutes). Following IV doses of 750 mg and 1.5 g, serum concentrations were approximately 50 and 100 mcg/mL, respectively, at 15 minutes. Therapeutic serum concentrations of approximately 2 mcg/mL or more were maintained for 5.3 hours and 8 hours or more, respectively. There was no evidence of accumulation of cefuroxime in the serum following IV administration of 1.5-g doses every 8 hours to normal volunteers. The serum half-life after either IM or IV injections is approximately 80 minutes.

Approximately 89% of a dose of cefuroxime is excreted by the kidneys over an 8-hour period, resulting in high urinary concentrations.

Following the IM administration of a 750-mg single dose, urinary concentrations averaged 1,300 mcg/mL during the first 8 hours. Intravenous doses of 750 mg and 1.5 g produced urinary levels averaging 1,150 and 2,500 mcg/mL, respectively, during the first 8-hour period.

The concomitant oral administration of probenecid with cefuroxime slows tubular secretion, decreases renal clearance by approximately 40%, increases the peak serum level by approximately 30%, and increases the serum half-life by approximately 30%. Cefuroxime is detectable in therapeutic concentrations in pleural fluid, joint fluid, bile, sputum, bone, and aqueous humor.

Cefuroxime is detectable in therapeutic concentrations in cerebrospinal fluid (CSF) of adults and pediatric patients with meningitis. The following table shows the concentrations of cefuroxime achieved in cerebrospinal fluid during multiple dosing of patients with meningitis.