title: ¹³C solid-state NMR analysis of the most common pharmaceutical excipients used in solid drug formulations Part II: CP kinetics and relaxation analysis.
abstract: Excipients used in the solid drug formulations differ in their NMR relaxation and (13)C cross-polarization (CP) kinetics parameters. Therefore, experimental parameters like contact time of cross-polarization and repetition time have a major impact on the registered solid state NMR spectra and in consequence on the results of the NMR analysis. In this work the CP kinetics and relaxation of the most common pharmaceutical excipients: anhydrous α-lactose, α-lactose monohydrate, mannitol, sucrose, sorbitol, sodium starch glycolate type A and B, starch of different origin, microcrystalline cellulose, hypromellose, ethylcellulose, methylcellulose, hydroxyethylcellulose, sodium alginate, magnesium stearate, sodium laurilsulfate and Kollidon(®) were analyzed. The studied excipients differ significantly in their optimum repetition time (from 5 s to 1200 s) and T(1ρ)(I) parameters (from 2 ms to 73 ms). The practical use of those differences in the excipients composition analysis was demonstrated on the example of commercially available tablets containing indapamide as an API. The information presented in this article will help to choose the correct acquisition parameters and also will save the time and effort needed for their optimization in the NMR analysis of the solid drug formulations.
authors.affiliation: Faculty of Pharmacy, Medical University of Warsaw, Department of Physical Chemistry, Banacha 1, 02-093 Warsaw, Poland. Electronic address: dpisklak@wum.edu.pl.
authors.forename: Dariusz Maciej
authors.initials: DM
authors.lastname: Pisklak
authors.affiliation: Faculty of Pharmacy, Medical University of Warsaw, Department of Inorganic and Analytical Chemistry, Banacha 1, 02-093 Warsaw, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Zielińska-Pisklak
authors.affiliation: Faculty of Pharmacy, Medical University of Warsaw, Department of Physical Chemistry, Banacha 1, 02-093 Warsaw, Poland.
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Szeleszczuk
authors.affiliation: Faculty of Pharmacy, Medical University of Warsaw, Department of Physical Chemistry, Banacha 1, 02-093 Warsaw, Poland.
authors.forename: Iwona
authors.initials: I
authors.lastname: Wawer
mesh_terms: D066241:Carbon-13 Magnetic Resonance Spectroscopy / Q000379:methods*; D002626:Chemistry, Pharmaceutical / Q000379:methods; D005079:Excipients / Q000737:chemistry*; D007190:Indapamide / Q000737:chemistry; D007700:Kinetics; D013607:Tablets / Q000737:chemistry*
chemical_list: D005079:Excipients; D013607:Tablets; D007190:Indapamide
keywords: CP kinetics; Contact time; Excipients; Repetition time; Solid drug forms; Solid-state NMR