Estudo comparativo de metodologias oficiais para doseamento de isoniazida em comprimidos

Abstract

Tuberculosis, an infectious disease whose etiological agent is Mycobacterium tuberculosis (MTB), is a public health problem of global interest. The drug treatment is extensive, and health authorities must monitor it to ensure its success in avoiding cases of recurrence and the emergence of resistant bacteria. One of the principal drugs used in this treatment is isoniazid, introduced in the 1950s and composes the therapeutic regimens against tuberculosis until the latter day. Because of the importance of using adequate doses for the success of the treatment, this work aimed to carry out the application of official methodologies for the dosage of isoniazid in tablets. In addition, we attempted to compare the techniques used, molecular absorption spectrophotometry in UV-Vis, and high-performance liquid chromatography (HPLC), highlighting advantages, disadvantages, difficulties, and possible improvements. Utilizing molecular absorption spectrophotometry in UV-Vis and using two different forms of calculation — direct comparison with a standard and construction of an analytical curve —, it reached the values of 97.4 % and 91.2 %, respectively, of the declared drug content, both within the standards established in the Brazilian Pharmacopoeia, 6th edition for isoniazid (minimum 90% and maximum 110% of the declared amount). The assay done by HPLC showed an 82.7% recovery. Nevertheless, it's worth mentioning that we achieved this result through an unofficial methodology. Both methodologies proved efficient for drug identification, but spectrophotometry showed to be easier to execute.