Comparative evaluation of ICP sample introduction systems to be used in the metabolite profiling of chlorine-containing pharmaceuticals via HPLC-ICP-MS

Probing the Electronic Properties and Interaction Landscapes in a Series of N-(Chlorophenyl)pyridinecarboxamides

A 3 × 3 isomer grid of nine N-(chlorophenyl)pyridinecarboxamides (NxxCl) is reported with physicochemical studies and single crystal structures (Nx = pyridinoyl moiety; xCl = aminochlorobenzene ring; x = para-/meta-/ortho-), as synthesized by the reaction of the substituted p-/m-/o-pyridinecarbonyl chlorides (Nx) with p-/m-/o-aminochlorobenzenes (xCl). Several of the nine NxxCl crystal structures display structural similarities with their halogenated NxxX and methylated NxxM relatives (x = p-/m-/o-substitutions; X = F, Br; M = methyl). Indeed, five of the nine NxxCl crystal structures are isomorphous with their NxxBr analogues as the NpmCl/Br, NpoCl/Br, NmoCl/NmoBr, NopCl/Br, and NooCl/Br pairs. In the NxxCl series, the favored hydrogen bonding mode is aggregation by N-H···N_pyridine interactions, though amide···amide intermolecular interactions are noted in NpoCl and NmoCl. For the NoxCl triad, intramolecular N-H···N_pyridine interactions influence molecular planarity, whereas NppCl·H₂O (as a monohydrate) exhibits O-H···O, N-H···O1W, and O1W-H···N interactions as the primary hydrogen bonding. Analysis of chlorine-containing compounds on the CSD is noted for comparisons. The interaction environments are probed using Hirshfeld surface analysis and contact enrichment studies. The melting temperatures (T _m) depend on both the lattice energy and molecular symmetry (Carnelley's rule), and the melting points can be well predicted from a linear regression of the two variables. The relationships of the T _m values with the total energy, the electrostatic component, and the strongest hydrogen bond components have been analyzed.

ICH Q3D based elemental impurities study in liquid pharmaceutical dosage form with high daily intake - comparative analysis by ICP-OES and ICP-MS

Guideline for Elemental Impurities-Q3D of the International Conference on Harmonisation represents a new paradigm in the control of elemental impurities (EIs) in pharmaceuticals. It changes the approach toward control of EIs from the historical 'heavy metals test', to a scientific-based risk assessment and testing by modern analytical instrumentation such as inductively coupled plasma-optical emission spectroscopy (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS). Management of EIs related to all finished drug products must be implemented in strict compliance with the regulatory requirements of pharmaceutical industry due to their quality and safety concerns. Testing for presence of EIs from Class 1 and Class 2a in methadone hydrochloride 1 mg/ml oral solution with recommended daily intake of 150 mg methadone hydrochloride was initially performed on ICP-OES using in-house validated method according to the requirements of pharmacopoeias, in line with Q3D. During the procedure, it became apparent that ICP-OES has its own limitations, especially when it comes to testing arsenic and lead in low concentrations. ICP-MS in-house validated method was developed and employed for determination of trace concentrations of arsenic and lead, providing resourceful information that were compared and correlated to the data obtained by ICP-OES analysis. Sample preparation using microwave digestion technique was applied for the analyses by both techniques. Although the applied ICP-OES in-house method is suitable for determination of Hg, Cd, Co, V, and Ni, more sensitive technique such as ICP-MS is required for accurate determination of As and Pb concerning pharmaceuticals with high daily intakes.

On the effect of using collision/reaction cell (CRC) technology in single-particle ICP-mass spectrometry (SP-ICP-MS)

In this work, the effects of using collision/reaction cell (CRC) technology in quadrupole-based ICP-MS (ICP-QMS) instrumentation operated in single-particle (SP) mode have been assessed. The influence of (i) various CRC gases, (ii) gas flow rates, (iii) nanoparticle (NP) sizes and (iv) NP types was evaluated using Ag, Au and Pt NPs with both a traditional ICP-QMS instrument and a tandem ICP-mass spectrometer. It has been shown that using CRC technology brings about a significant increase in the NP signal peak width (from 0.5 up to 6 ms). This effect is more prominent for a heavier gas (e.g., NH₃) than for a lighter one (e.g., H₂ or He). At a higher gas flow rate and/or for larger particle sizes >100 nm), the NP signal duration was prolonged to a larger extent. This effect of using CRC technology has been further demonstrated by characterizing custom-made 50 and 200 nm Fe₃O₄ NPs (originally strongly affected by the occurrence of spectral overlap) using different CRC approaches (H₂ on-mass and NH₃ mass-shift). The use of NH₃ (monitoring of Fe as the Fe(NH₃)₂⁺ reaction product ion at m/z = 90 amu) induces a significant peak broadening compared to that observed when using H₂ (6.10 ± 1.60 vs. 0.94 ± 0.49 ms). This extension of transit time can most likely be attributed to the collisions/interactions of the ion cloud generated by a single NP event with the CRC gas and it even precludes 50 nm Fe₃O₄ NPs to be detected when using the NH₃ mass-shift approach. Based on these results, the influence of a longer peak width on the accuracy of SP-ICP-MS measurement data (NP size, particle number density and mass concentration) must be taken into account when using CRC technology as a means to overcome spectral overlap. To mitigate the potential detrimental effect of using CRC technology in the characterization of NPs via SP-ICP-MS(/MS), the use of light gases and low gas flow rates is recommended.