Performance characteristics of methods of analysis used for regulatory purposes. I. Drug dosage forms. F. Gravimetric and titrimetric methods.

The original gravimetric and titrimetric methods approved by AOAC for the analysis of pharmaceutical preparations, particularly during the period 1915-1950, show precision, recovery, and outlier parameters approximately the same as those exhibited by the previously reviewed instrumental methods that are currently used. Fifty-nine published collaborative studies utilized gravimetric methods and 85 used titrimetric. The studies of the gravimetric methods encompassed 47 analytes, 95 dosage forms, and 136 assays; the corresponding figures for the titrimetric studies are 72, 112, and 152.

Quantitative liquid chromatography of ampicillin: collaborative study.

A previously published liquid chromatographic method proposed for official use for the analysis of ampicillin in the market place was subjected to an international collaborative study. The method is rigorously defined in terms of performance requirements, yet allows a degree of flexibility to the individual analyst. Twenty-four participating laboratories from 9 countries submitted results of analysis of 3 samples.

Quantitation of amphotericins by reverse-phase high-performance liquid chromatography.

A reverse-phase high-performance liquid chromatographic (HPLC) method was developed for simultaneous potency determination of amphotericin A and amphotericin B in bulk amphotericin B preparations. This single, rapid, specific, and simple method can be used for qualitative and quantitative analyses and is proposed to replace a combination of cumbersome official tests presently in use. This new HPLC method employs an isocratic acidic phosphate bufhotericin A and amphotericin B in bulk amphotericin B preparations.

High pressure liquid chromatographic determination of antihistamine-adrenergic combination products: collaborative study.

A reverse phase high pressure liquid chromatographic method in which ion-pairing is used for the determination of combinations of pseudoephedrine hydrochloride with triprolidine hydrochloride or chlorpheniramine maleate in syrups and tablets was collaboratively studied by 8 laboratories. Collaborators were supplied with 12 samples including synthetic and commercial syrup formulations and commercial tablet composites. Mean recoveries of pseudoephedrine hydrochloride and triprolidine hydrochloride from synthetic syrup formulations were 100.

GLC determination of N,N-dimethylaniline in penicillins.

A reliable GLC procedure was developed for the determination of residual N,N-dimethylaniline as a contaminant in ampicillin commerical samples from various sources. The procedure was similarly applied to other penicillins and cephalosporins. The method involves dissolution of the sample in aqueous alkali, extraction of the organic base with cyclohexane containing naphthalene as an internal standard, and injection into gas chromatograph with a phenyl methyl silicone column.

GLC analysis of griseofulvin: a collaborative study.

A GLC method for the assay of griseofulvin in bulk and dosage forms was subjected to a wide and rigorous collaborative study. An overall recovery of 99.52 plus or minus 2.