OTC Testing

Marzouk, Hoda M., et al. Microchemical Journal 178 (2022): 107400.

The determination of active pharmaceutical ingredients (APIs) and toxic impurities in over-the-counter (OTC) drugs is essential for ensuring their safety, efficacy, and regulatory compliance. This study presents two liquid chromatographic methods for the simultaneous quantification of paracetamol (PAR), aspirin (ASP), diphenhydramine (DIPH), and three toxic impurities (p-aminophenol, p-nitrophenol, and salicylic acid) in Excedrin® PM caplets, a widely used OTC formulation for pain, fever, and sleep aid, especially recommended for COVID-19 patients.

The first method employs high-performance thin-layer chromatography (HPTLC) with densitometric quantification, offering a simple, cost-effective approach for API analysis. The second method utilizes high-performance liquid chromatography (HPLC) coupled with a diode array detector (DAD), which provides more precise separation and quantification. Both methods were validated according to ICH guidelines and applied to quality control of the marketed formulation.

Additionally, the in-vitro release of the drugs was monitored using the HPLC-DAD method, confirming its suitability for comprehensive quality assessment. The greenness of both methods was evaluated using multiple eco-assessment tools (eco-scale, NEMI, GAPI, AGREE), ensuring their environmental compatibility. These methods are critical for ensuring the safe use of OTC medications, particularly in the context of increased demand during the pandemic.

Freitas, Jhonys M., et al. Microchemical Journal 160 (2021): 105757.

The adulteration of over-the-counter (OTC) weight-loss products with illicit drugs like ephedrine poses significant health risks and regulatory challenges. This study presents a novel, rapid, and portable method for the direct determination of ephedrine in OTC weight-loss products using a batch injection analysis system coupled with square-wave voltammetric detection (BIA-SWV) and a bare boron-doped diamond (BDD) electrode.

The method demonstrated a linear range of 5.0 to 40 mg/L for ephedrine with a low detection limit of 0.13 mg/L. Using a 0.1 mol/L acetate buffer (pH 4.7) as the supporting electrolyte, this technique enables precise and quick quantification of ephedrine without the need for sample pretreatment. The simplicity and portability of this system make it highly suitable for on-site criminal forensic analysis and anti-doping control, especially for detecting ephedrine in urine samples.

The potential applications of this method extend to ensuring the safety and compliance of OTC products, particularly in preventing the illegal adulteration of weight-loss products. Given the rapid detection capabilities and ease of use, this approach offers an effective tool for regulatory authorities, ensuring that OTC products are free from harmful substances.

Fakayode, S. O., Bolton, B., Dassow, B., Galvez, K., & Chohan, H. (2024). Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 305, 123447.

Over-the-counter (OTC) oral syrups are commonly used for treating ailments, but their counterfeiting poses serious health risks. This study presents a rapid and effective quality assurance method for OTC oral syrups using Raman and UV-visible spectroscopy, combined with Principal Component Analysis (PCA) and Partial-Least-Squares (PLS) regression. This method addresses the challenges of verifying the active ingredient concentrations in OTC oral syrups without the need for sample extraction.

The PLS regression analysis of UV-visible absorption spectra successfully quantifies key active components, including acetaminophen, guaifenesin, dextromethorphan HBr, and phenylephrine HCl. The method demonstrated high linearity (R² > 0.9784) and sensitivity, with detection limits as low as 0.02 mg/mL for acetaminophen and guaifenesin. The simultaneous quantification of multiple active ingredients showed accuracies ranging from 88% to 94%, ensuring that the formulations meet the required specifications.

This approach offers significant benefits for quality control in the pharmaceutical industry, enabling rapid, non-destructive analysis in both laboratory and field settings. The combination of Raman and UV-visible spectral profiling, along with advanced data analysis techniques like PCA and PLS regression, provides a robust tool for monitoring the integrity of OTC oral syrups and preventing counterfeiting, ensuring patient safety.