Quantitation of insulin injection by high-performance liquid chromatography and high-performance capillary electrophoresis.

High-performance capillary electrophoresis (HPCE) was evaluated as a potential technique for the regulatory analysis of commercial dosage forms of insulin. A comparison was made to a liquid chromatographic analysis presently being proposed as an official monograph in the United States Pharmacopeia. The salient points of this comparison were accuracy, precision and ease of use. Both authentic (i.e. single blind, spiked) samples and commercial pharmaceutical formulations (injections) were examined. Chromatographic analyses of both commercial formulations and authentic samples were characterized by good precision, with accuracy being supported by results from authentic (spiked) samples. Conventional HPCE (by which is meant a non-micellar electrolyte used with an uncoated, unmodified fused-silica capillary) achieved reasonable accuracy, but less than impressive precision, when applied to authentic samples. When used for commercial formulations, this type of HPCE did not produce a level of accuracy suitable for regulatory purposes, even with the use of an internal standard.

Determination of iodide and thiosulfate by paired-ion, reversed-phase high-performance liquid chromatography with ultraviolet absorbance, electrochemical, and conductimetric detection.

Inorganic anions are typically determined by ion chromatography, ion-selective electrodes, or by "wet chemical" procedures. An alternative to these approaches is afforded by paired-ion, reversed-phase high-performance liquid chromatography (HPLC), and the application of this technique to the determination of iodide and thiosulfate is discussed. Each analyte can be determined using ultraviolet (UV) absorbance detection and oxidative, amperometric electrochemical detection (ED). Furthermore, in the case of iodide, an additional and quite selective ED scheme is available through the use of series-configured dual glassy carbon electrodes. The dual-series ED approach utilizes an upstream electrode which is maintained at an oxidative potential. This results in the formation of an electroactive species, which may be detected at a downstream electrode held at a reductive potential. Finally, it is demonstrated that non-suppressed conductimetric detection is also perfectly viable within the context of paired-ion, reversed-phase HPLC, provided the overall conductance of the mobile phase is not excessive.

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 100.5 and 99.6%, respectively. Mean recoveries of pseudoephedrine hydrochloride and chlorpheniramine maleate from synthetic syrups were 98.8 and 100.5%, respectively. Mean coefficients of variation for syrups and tablets ranged from 1.68 to 3.07% for pseudoephedrine hydrochloride, from 2.92 to 3.85% for triprolidine hydrochloride, and from 1.34 to 2.15% for chlorpheniramine maleate. The method has been adopted official first action.