Analytical Validation of an HPLC-DAD Method for Ivermectin Quantification in Polymeric Nanocapsules

Ivermectin (IVM) is a broad-spectrum antiparasitic drug whose clinical application is limited by poor aqueous solubility, chemical instability, and pharmacokinetic variability. Polymeric nanocapsules represent a promising strategy to overcome these limitations. However, their complex composition requires reliable and selective analytical methods for accurate drug quantification. In this study, a reversed-phase HPLC-DAD method was developed and validated for the quantification of ivermectin and applied to polymeric nanocapsules, including the determination of encapsulation efficiency and drug loading. Chromatographic separation was achieved on a C18 column using isocratic elution with acetonitrile and purified water (90:10, v/v) with diode-array detection at 253 nm and a retention time of approximately 4.7 min. The method was validated according to ICH Q2-(R2) guidelines, demonstrating adequate selectivity through evaluation of matrix interference and analysis under stress conditions. Linearity was observed over the analytical range (R² > 0.99), while accuracy and precision were satisfactory, with recovery values close to 100% and relative standard deviation below 2%. Application of the method to polymeric nanocapsules resulted in high encapsulation efficiency. A preliminary evaluation of chemical stability over 30 days indicated that ivermectin content remained above 95% under the evaluated storage conditions. Overall, the proposed method is simple, selective, precise, accurate, robust, and suitable for the quantitative analysis of ivermectin in complex nanostructured formulations.