Comparison of the iodogen and the microelectrochemical techniques for the radioiodination of monoclonal antibody 140.240.

The Iodogen technique was compared with the microelectrochemical technique for the radioiodination of submilligram quantities of monoclonal antibody 140.240. The titre of the antibody against cultured melanoma cells was decreased five-fold after iodination with 0.80-0.85 atoms of iodine per molecule of antibody with both techniques. The Iodogen technique resulted in 82.1% incorporation of iodine into the antibody, somewhat higher than the 78.0% obtained with the microchemical technique (P = 0.10). Therefore, the Iodogen technique is the preferred method based on efficiency and convenience.

High-pressure liquid chromatographic assays for ticarcillin in serum and urine.

Rapid and sensitive high-pressure liquid chromatographic (HPLC) assays for ticarcillin in serum and urine have been developed. Sample pretreatment and optimized chromatographic conditions are presented for a C-18-bonded reversed-phase column used in an internal standard assay method. Ticarcillin has a retention time of or approximately 5.3 min at a flow rate of 1.5 ml/min for a mobile phase of acetonitrile-aqueous 0.06 M sodium biphosphate, pH 2.05, (50.5:100). In a two-step extraction procedure, the ticarcillin extraction efficiencies from serum and urine were 76.1 +/- 4.7 and 80.9 +/- 3.2% respectively. The assay sensitivity limit for ticarcillin in these fluids is approximately 1.0 microgram/ml. A comparison is made of the HPLC and microbiological assay results for ticarcillin in 20 different but equally divided serum samples obtained from two volunteers.

High-pressure liquid chromatographic assay of cloxacillin in serum and urine.

Two rapid, specific, and sensitive high-pressure liquid chromatographic (HPLC) assays were developed for cloxacillin in serum and urine. A reversed-phase column (RP-8) was selected for use with two different sets of HPLC conditions and sample pretreatment procedures. Cloxacillin extraction efficiencies are reported from serum and urine. Equations are presented for linear relationships between peak height or peak area ratios of cloxacillin to nafcillin (internal standard) and the cloxacillin concentration over a range of 0-80 micrograms/ml. The sensitivity limit of these assays was approximately 0.3 microgram/ml of a standard solution for one method and 0.05 microgram /ml for the other HPLC assay.

Determination of flucytosine in tablets by differential pulse polarography.

A differential pulse polarographic assay was developed for determining flucytosine in tablets. The drug is extracted from the sample with water and hydrochloric acid and, after the pH is adjusted, an aliquot is added to the cell and the solution is polarographed at the dropping mercury electrode versus the saturated calomel electrode with 0.066 M Sørensen phosphate buffer (pH 5.6) as the supporting electrolyte. The polarographic peak height enables precise quantitative determination. The Ep value for flucytosine is--1.54 v versus the saturated calomel electrode. The mean recovery of the drug is 101.5% +/- 1.9 (SD). The method is simple, rapid, and precise.

Short- and long-term cadmium distribution in rat livers after different routes of administration.

Intracellular hepatic distribution of cadmium in male Wistar rats were determined after various time intervals up to 6 months following a single intraperitoneal injection of cadmium chloride (3.75 mg/kg). After an initial liver accumulation period of approximately 2 weeks, cadmium was slowly eliminated. This decrease occurred primarily in the soluble fraction, but also to a lesser extent in the nuclear and mitochondrial fractions. No detectable decrease of cadmium was observed in the microsomal fraction. There was no apparent redistribution of cadmium within these hepatic fractions during the 6-month period of study. A comparison of the intracellular cadmium distribution following administration by intraperitoneal, oral, and pulmonary routes revealed that in each instance the soluble fraction contained the greatest amount of this element by far with decreasing amounts in the microsomes, mitochondria, and nuclei in that order.

Determination of fluoxymesterone, norethandrolone, prednisolone, and prednisone in tablets by differential pulse polarography.

A differential pulse polarographic method for the determination of fluoxymesterone, norethandrolone, prednisolone, and prednisone in tablets is described. This method is more sensitive than dc polarography, and the measurement of diffusion current is greatly simplified. Sørensen phosphate buffer, pH 5.6, was used as the supporting electrolyte. No apparent interference was observed from tablet excipients; the method is rapid, simple, and relatively precise.