A high-performance liquid chromatographic assay for clindamycin phosphate and its principal degradation product in bulk drug and formulations.

A high-performance liquid chromatography method has been developed for the analysis of clindamycin phosphate and clindamycin, the principal degradation product. The method is quantitative, precise and is able to separate a variety of closely related molecules. The method has been applied to bulk drug, topical and sterile solutions, and experimental cream, lotion and gel formulations. The method gives results that are in good agreement with the official gas chromatographic method but is much less time-consuming.

Cytosine arabinoside stability in intravenous admixtures with sodium bicarbonate and in plastic syringes.

The increased use of high-dose cytarabine in the treatment of neoplasms prompted this study on the reconstituted stability of cytarabine in intravenous admixtures with sodium bicarbonate and in plastic syringes. The study of the effect of sodium bicarbonate was prompted by the frequent use of this agent in patients being treated with cytarabine as a means of achieving systemic alkalinization in order to manage hyperuricemia. The stability of reconstituted cytarabine in plastic syringes was measured to determine whether cytosine arabinoside could be reconstituted and stored prior to use. The results of this study indicate that sodium bicarbonate 50 mEq/L in the intravenous solution containing cytarabine has no effect on the chemical stability of cytarabine for at least one week at room temperature or in the refrigerator. Consequently sodium bicarbonate and cytarabine can be coadministered in one intravenous solution. The reconstituted stability of cytarabine at 20 mg/ml and 50 mg/ml is not affected by storage in plastic syringes.

Analysis of iodochlorhydroxyquin in cream formulations and bulk drugs by high-performance liquid chromatography.

A high-performance liquid chromatographic method for the analysis of iodochlorhydroxyquin in creams and as bulk drugs has been developed. Iodochlorhydroxyquin was acetylated in the 8-position by reaction with acetic anhydride in pyridine. The resulting ester was mixed with the internal standard and chromatographed on a microparticulate silica column. Recovery was quantitative and the method was shown to be applicable to cream formulations from several manufacturers.

Determination of dextromethorphan hydrobromide by high-performance liquid chromatography using ion-pair formation.

The chromatographic retention behavior of dextromethorphan hydrobromide on an octadecylsilane column was investigated as a function of the pairing ion and the mobile phase composition. Dramatic increases in the capacity factor were observed with pairing ions containing more than eight carbons and with decreasing organic modifier (acetonitrile) concentration. Several pharmaceutically important amines exhibited similar behavior with respect to acetonitrile concentration. An analytical method was developed for dextromethorphan hydrobromide bulk drug and syrups and was applied to commercial preparations.

High-performance liquid chromatographic analysis of codeine in syrups using ion-pair formation.

The chromatographic behavior of morphine, codeine, and ethylmorphine was examined using reversed-phase high-performance liquid chromatography and ion-pair formation. Alkyl sulfonates and sulfates significantly increased the retention times for these compounds. The carbon chain length of the pairing ions was linearly related to the log of the capacity factors of these amine drugs. A mechanism for the increased retention based on ion-pair formation in the mobile phase is proposed. The use of dioctyl sodium sulfosuccinate as a pairing ion for codeine is described, and a method utilizing this pairing ion was developed for the quantitation of codeine in syrups. This method was applied successfully to various syrups containing codeine or codeine phosphate.

Infrared detection of fatigue cracks and other near-surface defects.

This paper describes a noncontacting, nondestructive inspection system that can rapidly locate, in real time, the position and extent of fatigue cracks in aircraft and missile structures. The automated ir system described was developed for the USAF for use in their Sonic Test Facility at Wright-Patterson AFB. This facility is capable of subjecting large aircraft or missile structures to the intense sound fields experienced in actual flight or launch. In addition to presenting the basic concepts of the method, this paper (1) describes briefly the design of the system that was developed for the USAF, (2) discusses test results, and (3) presents conclusions and indicates future applications of the technique.