Development of an Analytical Procedure for the Quantitative Determination of Choline in Ear Drops Based on Viscum album Leaf Soft Extract

INTRODUCTION. A new ear drop composition based on European mistletoe (Viscum album L.) leaf soft extract was developed to meet the demand for cerumenolytic ear drops. The registration dossier for this medicinal product must include an analytical procedure for the quantitative analysis of the main active substance in V. album leaf soft extract (choline).

AIM. This study aimed to develop and validate an analytical procedure for the quan­titative determination of choline in cerumenolytic ear drops based on V. album leaf soft extract.

MATERIALS AND METHODS. The presence of nitrogenous bases was determined by paper chromatography. Munktell chromatography paper (grade FN7, size 4×25 cm) was used as the stationary phase. The mobile phase consisted of the following solvent systems: n-butanol — ethanol — acetic acid — water (8:2:1:3), n-butanol — acetic acid — water (4:1:5), and acetic acid — water (15:85). The colour development reagent was iodine vapour. The spectrophotometric determination of nitrogenous bases was conducted using an SF-102 spectrophotometer and a detector at a wavelength of 400±2 nm in the presence of ammonium reineckate (Reinecke’s salt). The analytical procedure for the quantitative determination of choline ethers was validated for specificity, linearity, accuracy, and precision.

RESULTS. This study developed and validated a spectrophotometric analytical procedure for the quantitative determination of choline ethers calculated as choline in cerumenolytic ear drops based on V. album leaf soft extract in the presence of Reinecke’s salt. The analytical procedure identified choline and its esters (acetylcholine, acetylcholine iodide, and benzoylcholine) in the analysed ear drops. The content of choline esters calculated as choline was 0.710±0.018%.

CONCLUSIONS. The spectrophotometric analytical procedure for the quantitative determination of choline ethers in the presence of Reinecke’s salt can be recommended for the quality control of cerumenolytic ear drops based on V. album leaf soft extract.

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