Interchangeability of Pyridostigmine Bromide Tablets of South American Countries

GONZALEZ VIDAL, N. L.; SIMIONATO, L. D.; ZUBATA, P. D.; ERCOLANO, I.; PIZZORNO, M. T.

Orlando, Florida, USA

Congreso; 119th AOAC Annual Meeting & Exposition; 2005

AOAC International

The characteristic of myasthenia gravis need to assure that tablets of Pyridostigmine Bromide of different sources produce the same therapeutical response to be interchangeable. We decided to analyze the pharmaceutical forms traded in three neighbor countries of South America. Pyridostigmine is a quaternary ammonium compound, which is a reversible inhibitor of cholinesterase activity, poorly absorbed from the gastro-intestinal tract and very hygroscopic, almost deliquescent. It is considered a Class III drug in the Biopharmaceutics Classification System, due to its high solubility and low permeability. Pyridostigmine Bromide (60 mg) Inmediate Release tablets were purchased from pharmacies of countries A, B and C and analyzed following USP 27. All analyzed formulations fulfilled the assay, uniformity of dosage units and dissolution test in S2 stage. The similarity factor f2 was applied to dissolution profiles. The formulation of country B could not be included in that determination since it did not fulfill the requirements, showing a high variability at first sampling point and a single value below 85% dissolved in its dissolution profile. Formulations of counties A and C are similar, with an f2 of 64.0. The results in this study let us to conclude that, though, all the analyzed formulations met the required pharmaceutical quality standards (including dissolution test codified in USP), their dissolution profiles are not equivalent between them, with potential impact on in vivo bioavailability. We conclude that the analyzed dosage forms from countries A and C are interchangeable between them, but not with that obtained from county B.