Liquid chromatography-mass spectrometry for simultaneous determination of spironolactone and canrenone in plasma samples

Abstract n our study, we aimed to validate a method based on liquid chromatography-mass spectrometry (LC-MS) to quantify spironolactone (SPI) and its active metabolite canrenone (CAN) simultaneously in plasma samples to support in vivo experiments. Compounds were separated by using a C18 column with the isocratic elution of a mobile phase composed of 0.1% (v/v) formic acid in methanol-water (60:40 v/v) at a flow rate of 0.4 mL min−1. SPI and CAN were detected in na electrospray interface operating in a positive ionization mode and quantified using the selective ion mode monitoring of mass-charge ratios (m/z) of 439.0 for SPI and 363.1 for CAN. After calculating the matrix effect using theoretical equations, we observed the strong interference of plasma in the equipment-generated signal, which required creating analytical curves using the matrix as a solvent. The method was nevertheless linear (r 2 > 0.999) in a concentration range of 0.4-5.0 µg mL−1, as well as precise, with a coefficient of variation less than 5%. SPI's and CAN's recovery rates from the plasma ranged from 87.4% to 112.1%, while their limits of detection (i.e., 0.07 µg mL−1 and 0.03 µg mL−1, respectively) and quantification (i.e., 0.20 µg mL−1 and 0.08 µg mL−1, respectively) in the presence of plasma contaminants were low. Therefore, the bioanalytical method seems to be feasible for quantifying SPI and CAN in plasma

Analysis of spironolactone polymorphs in active pharmaceutical ingredients and their effect on tablet dissolution profiles

ABSTRACT Spironolactone (SPR) is a steroidal drug administered as a potassium-sparing diuretic for high blood pressure treatment. The drug shows incomplete gastrointestinal absorption due to its poor aqueous solubility. The physicochemical properties of SPR in crystal forms I and II suggest that differences in their aqueous solubility may lead to a lack of bioequivalence between solid-state formulations. In this study, SPR polymorphs in five batches of active pharmaceutical ingredients (APIs) from three manufacturers were characterized using powder X-ray diffraction, infrared spectroscopy, thermal analysis, and solubility measurements. SPR tablets (50 mg) were manufactured in our laboratory using API in pure form II, and API in form II contaminated with form I, which was found in a commercial batch. Physicochemical quality evaluations of the manufactured tablets, along with five SPR tablets marketed in Brazil, were performed, and results indicated differences in their dissolution profiles. In the manufactured tablets, differences were associated with the increased solubility of API in form II contaminated with form I compared to API in pure form II. In the marketed SPR tablets, the formulation composition demonstrated an important role in the dissolution rate of the drug, leading to lack of pharmaceutical equivalence among the drug products.

Sindrome dos ovarios policisticos: contribuicao para o estudo da resistencia a insulina / Polycystic ovary syndrome: contribution for the study of insulin resistance

Apos uma avaliacao inicial, 25 pacientes com sindrome dos ovarios policisticos (SOP) foram submetidas a teste de tolerancia a glicose oral com dosagens de glicose e insulina. Treze pacientes foram tratadas com espironolactona, 200 mg/dia por 6 meses e reavaliadas aos 3 e 6 meses. Concluimos que : 1- a SOP esta associada com a resistencia a insulina; 2- insulinemia de jejum nao e suficiente para o diagnostico; 3- mulheres obesas com acanthosis nigricans sao mais resistentes a insulina e 4- o uso de um antiandrogenio melhora a...