Preliminary studies for ciclopirox olamine determination by thermal lens spectrophotometry

•A thermal lens spectroscopy has been applied to the determination of ciclopirox olamine (CXO).•We had set up and evaluated a He-Ne single-beam thermal lens configuration.•Parameters and optimal conditions for the kinetic method and detection performance were studied.•Quantification of CXO in water by TLS detection has been shown to be a sensitive and reliable technique.•We introduce preliminary studies for the determination in tap water samples and is applicable to biopharmaceutical samples.

The spectrophotometric kinetic methods are broadly used in the determination of drugs in several types of matrices. Thermal Lens Spectrometry (TLS) has demonstrated to be a sensitive indirect spectrophotometric technique used in the field of applied sciences, such as environmental and biochemical sciences. Ciclopirox olamine (CXO) is a synthetic fungicide that inhibits the growth of pathogenic dermatophytes. This work presents the results of CXO determination by TLS, through a kinetic method, based on the CXO oxidation with KMnO4 in alkaline medium to form manganate (MnO42 −). The Thermal Lens (TL) effect was generated by a He-Ne laser (TEM00, 20 mW, 632 nm). The TLS measurements were performed on a single beam assembly with a lens of f = 7.5 cm focal distance and 10 Hz modulation frequency. The TL signal from the detector was acquired for each sample. The optimization was at 30 min reaction time, KMnO4 8.0 · 10− 4 mol L− 1 and Na2SO4 0.6 mol L− 1. Under these conditions a calibration curve was constructed. The analytical features were LOD = 3.40 μmol L− 1 and LOQ = 11.3 μmol L− 1. To examine accuracy and reliability, the determination method was successfully applied in tap water samples where known amounts of CXO were spiked.