Researchers at Georgia College and Purdue University have developed a fast, low-cost method using Raman and UV–visible spectroscopy combined with chemometric modeling to accurately screen and quantify active ingredients in over-the-counter oral syrups, helping to fight counterfeit medications.
A New Weapon Against Counterfeit Medications
As counterfeiting of over-the-counter medications (OTCMs) grows worldwide, a team of researchers has demonstrated a promising new tool for rapid quality assurance of oral medication syrups. The method uses Raman and UV–visible spectroscopy, coupled with advanced multivariate analysis, to quickly identify and quantify key active ingredients, without the need for extraction or complex sample preparation (1,2).
This novel approach was developed by Sayo O. Fakayode, Brinkley Bolton, Bailey Dassow, Kairy Galvez, and Harmeet Chohan of Georgia College and State University and Purdue University. Their work, recently published in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, could improve drug screening at every point in the supply chain (1).
Mother giving over-the-counter (OTC) cough syrup to reluctant daughter in bed © moodboard -chronicles-stock.adobe.com
Spectroscopy Tackles a Growing Global Health Threat
OTCMs are a cornerstone of self-care, especially in underserved regions where access to physicians or prescription medications may be limited. But with the growing demand has come increasing danger: counterfeit drugs that may lack proper active ingredients or contain harmful substitutes (1,2).
“Nearly 40% of medications imported into the U.S. and 80% of drug components originate abroad, creating opportunities for counterfeit or adulterated products to enter the supply chain,” the researchers noted, (1). With standard testing tools like chromatography and mass spectrometry (MS) requiring expensive instrumentation, long analysis times, and complex logistics, the need for portable, rapid, and cost-effective analysis techniques has never been greater (1).
Fast and Accurate Testing with Spectroscopy and Chemometrics
The team’s technique uses Raman spectroscopy, a laser-based method that detects molecular vibrations, alongside UV–visible absorption spectroscopy, which measures how much light is absorbed by different compounds. Both techniques are well-suited for field analysis, requiring no elaborate sample preparation and delivering fast results (1).
The spectroscopic data were then processed using principal component analysis (PCA) for pattern recognition and partial least squares (PLS) regression to determine concentrations of key ingredients—acetaminophen, guaifenesin, dextromethorphan HBr, and phenylephrine HCl—in flavored (sugar or sugar-free) syrup formulations (1).
According to the study, the PLS models showed excellent predictive performance, with R² values exceeding 0.9784 and detection limits as low as 0.02 mg/mL for acetaminophen and guaifenesin. Simultaneous quantification of all four active compounds achieved accuracies ranging from 88 to 94% (1).
Real-World Testing in Real-World Matrices
One major strength of this research was its use of syrup bases identical to those used in commercial products. Unlike some past studies that used simplified solvents or dried samples, this study kept the analysis environment close to that of actual OTCM formulations, including flavors, binders, dyes, and preservatives (1).
“This protocol is practical for routine quality checks,” the authors wrote, “as it allows direct analysis of syrup OTCMs without requiring extraction or drying.” Such adaptability makes the method well-suited for in-situ testing, regulatory monitoring, and even on-line analysis during drug manufacturing (1).
A Scalable Tool for Regulatory Agencies and Manufacturers
Given the method’s speed, accuracy, and minimal operational costs, it could be deployed broadly by quality control officers, pharmacists, and regulatory agencies to combat the spread of counterfeit medications, especially in rural and resource-limited settings (1).
While Raman and UV–visible spectroscopy have been individually used in pharmaceutical analysis, the study emphasizes the synergistic power of combining them with PCA and PLS regression for enhanced detection and quantification (1).
As the global demand for OTCMs grows, tools like this may help ensure that what consumers see on the label matches what’s inside the bottle.
References
(1) Fakayode, S. O.; Bolton, B.; Dassow, B.; Galvez, K.; Chohan, H. Rapid Screening and Multicomponent Quantifications of Active Components of Oral Syrup Over-the-Counter Medications by Raman and UV–Visible Spectroscopy and Multivariate Regression Analysis. Spectrochim. Acta, Part A 2024, 305, 123447. DOI: 10.1016/j.saa.2023.123447
(2) Goicoechea, H. C.; Olivieri, A. C. Determination of Bromhexine in Cough–Cold Syrups by Absorption Spectrophotometry and Multivariate Calibration Using Partial Least-Squares and Hybrid Linear Analyses. Application of a Novel Method of Wavelength Selection. Talanta 1999, 49 (4), 793–800. DOI: 10.1016/S0039-9140(99)00080-6
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