Elemental Impurities Determination by ICP-AES / ICP-MS: A review of Theory, Interpretation of Concentration Limits, Analytical Method Development Challenges and Validation Criterion for Pharmaceutical Dosage Forms

: Inductively coupled plasma is a new technique employed for the determination of elemental impurities in pharmaceutical ingredients viz. raw materials, drug substance, and drug product dosage forms. New US FDA and EMA regulations came into effect from Jan 2018 as industry standard requirements for the determination of inorganic elemental impurities using ICP-OES/AES or ICP-MS analytical techniques. The method development was optimized for the determination of the listed elements as per USP <232> <233> elemental impurities-limits and procedures. It also demonstrates the validation of the method and verification/transfer of the method which also provides an insight into the presence of free elemental atomics of the gaseous form of the sample (drug substance, drug product or excipients), thus helping in determining the concentration of the element of interest. Also, the regulatory guidance is very general and does not explain the sample specifications for the individual element concentrations. Thus, this review emphasizes the routine instrumental maintenance, analytical method development challenges, trends in the performance of analytical method validation and verification/ transfer activities of the various pharmaceutical dosage forms outlined with acceptance criterion.