Qualitative discrimination of low-dose oral contraceptives and identification of environmentally stressed tablets: Comparing a handheld near infrared spectrometer to a benchtop spectrometer

Abstract

Levonorgestrel – ethinyl estradiol tablets (Levo-EE) are an essential medication provided through global health supply chains for family planning purposes. Ensuring the quality of Levo-EE and other essential medications in a global supply chain is a primary concern. Portable and handheld diffuse reflectance spectrometers have become more approachable from a cost and usability perspective in recent years. A discriminatory screening method with a handheld near infrared (NIR) spectrometer (900 – 1700 nm) differentiating between brands of Levo-EE and placebos has been constructed. Additionally, the handheld spectrometer was used to determine if environmentally stressed tablets could be identified and differentiated in a qualitative screening method. The same samples were scanned on a benchtop diffuse reflectance NIR spectrometer as well (350 – 2500 nm) for comparison. Brands of oral contraceptives were able to be discriminated by applying a Mahalanobis distance-based classification approach to the handheld spectrometer, though be it at a slightly lower level of discernability due to the reduced spectral range collected. Environmentally stressed samples were applied to the classification model, which were flagged as unlike the reference dataset. Spectra from the environmentally stressed tablets saw an increase in absorbance for water associated peaks with the benchtop spectrometer at approximately 1450 nm and 1949 nm for tablets stored at 30, 40, and 50°C–54°C. Data collected by the handheld showed that the spectrometer offers a low-cost screening approach to oral contraceptive tablets containing two low-dose active ingredients. The handheld spectrometer was also able to flag environmentally stressed samples. The total model accuracy for the target product (brand “A”; N = 560) was above 98% for both benchtop and handheld spectrometers. While these results focus on oral contraceptives, a similar approach could be conducted for other solid dosage tablets for more approachable quality compliance screening.