In the present article it is described the validation of a simple, precise, accurate, rapid and low-cost UV spectrophotometric method for the quantification of acetylsalicylic acid in pharmaceutical formulations. The method was validated by linearity, specificity, range, accuracy, precision, robustness, and limits of detection and quantification. The method was linear in the range between 24 – 36 µg mL-1, presenting a good correlation coefficient (r = 0.9994) and adequate limits of quantification (6.57 µg mL-1) and detection (1.99 µg mL-1). Precision analysis showed low coefficient of variation (< 2.0%) and a good average recovery percentual (99.42% - reference and 95.94% - generic). The results and the statistical treated proved that the method may be considered a precise, accurate and low cost analytical alternative for laboratory routine and experimental activity. The method was applied for acetylsalicylic acid determination in two different pharmaceuticals formulations. The results of these analyzes are in accordance with the values declared by the manufacturer, at a 95% confidence level. This experimental activity is a simple and might be used as an practice activities on teaching laboratories improve the student learning.

In the present article it is described, a simple, precise, rapid and low-cost conductometric titration of tetracycline hydrochloride in pharmaceutical formulations using silver nitrate as titrant. The method is based on the precipitation of chloride ions derived from tetracycline hydrochloride with silver ions, yielding silver chloride precipitate and the conductance of the solution is measured as a function of the volume of titrant. The coefficient of variation for six successive measurements was 0.64% and no interferences were observed in the presence of common components of the pharmaceutical formulations. Recovery values from two samples, ranging from 99.0 to 105%, were obtained. The method was applied for tetracycline hydrochloride determination in two pharmaceuticals formulations and these results are in good accordance with the declared values of manufacturer and an official method of the Brazilian Pharmacopoeia, based on spectrophotometric analysis, at a 95% confidence level.