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The United States Pharmacopeia (USP) sets quality, purity, strength, and identity standards for medicines, food ingredients, and dietary supplements. Many USP standards are enforceable by the United States Food and Drug Administration (FDA) under US law. When standards become more stringent, testing laboratories can face new challenges.
On January 1, 2018 USP enacted new criteria for element impurities in finished drug products. These criteria, detailed in USP <232>/<233>, recommend analysis of drug products for element impurities by either ICP-AES or ICP-MS. Drug products may be oral, parenteral (injected), or inhaled. Laboratories must measure impurities based on a J value for each drug product. The J value of the drug is calculated based on an established permissible daily exposure (PDE), maximum daily dose of the drug (MDD), and the dilution factor used in the sample preparation method. As a result of the J value calculation, drugs with a larger MDD require lower element impurity detection limits.
The Teledyne CETAC U5000AT+ Ultrasonic Nebulizer is an accessory for ICP-AES that enables higher sample transport efficiency (versus a standard pneumatic nebulizer) to the ICP-AES plasma. This benefit can be helpful for detection of more difficult elements such as As, Cd, Pb, Sb, and Tl.
This example describes the use of the U5000AT+ for ICP-AES detection of element impurities in aspirin, a drug with a higher daily dose than drugs with a low dose (for example, one tablet per day) such as an allergy or sleep aid medicine.
The graph shows the signal intensity at 188.987 nm from arsenic (As) spiked into aspirin digest with a J value of 30 μg/L. The blue spectra line is using an U5000AT+ ultrasonic nebulizer and the green spectra line is using a standard nebulizer. The U5000AT+ enables an approximately seven-fold increase in arsenic signal sensitivity.
Click below to download a poster about this application of the U5000AT+ ultrasonic nebulizer.
