title: Comparison of Univariate and Multivariate Models of ¹³C SSNMR and XRPD Techniques for Quantification of Nimodipine Polymorphs.
abstract: The focus of the present investigation was to explore the use of solid-state nuclear magnetic resonance ((13)C ssNMR) and X-ray powder diffraction (XRPD) for quantification of nimodipine polymorphs (form I and form II) crystallized in a cosolvent formulation. The cosolvent formulation composed of polyethylene glycol 400, glycerin, water, and 2.5% drug, and was stored at 5°C for the drug crystallization. The (13)C ssNMR and XRPD data of the sample matrices containing varying percentages of nimodipine form I and form II were collected. Univariate and multivariate models were developed using the data. Least square method was used for the univariate model generation. Partial least square and principle component regressions were used for the multivariate models development. The univariate models of the (13)C ssNMR were better than the XRPD as indicated by statistical parameters such as correlation coefficient, R (2), root mean square error, and standard error. On the other hand, the XRPD multivariate models were better than the (13)C ssNMR as indicated by precision and accuracy parameters. Similar values were predicted by the univariate and multivariate models for independent samples. In conclusion, the univariate and multivariate models of (13)C ssNMR and XRPD can be used to quantitate nimodipine polymorphs.
authors.affiliation: Center for Drug Evaluation and Research, Office of Testing and Research, Division of Product Quality Research, Food and Drug Administration, White Oak, LS Building 64, Room 1070, 10903 New Hampshire Ave, Silver Spring, Maryland, 20993 002, USA.
authors.forename: Ziyaur
authors.initials: Z
authors.lastname: Rahman
authors.affiliation: Center for Drug Evaluation and Research, Office of Testing and Research, Division of Product Quality Research, Food and Drug Administration, White Oak, LS Building 64, Room 1070, 10903 New Hampshire Ave, Silver Spring, Maryland, 20993 002, USA.
authors.forename: Adil
authors.initials: A
authors.lastname: Mohammad
authors.affiliation: Center for Drug Evaluation and Research, Office of Testing and Research, Division of Product Quality Research, Food and Drug Administration, White Oak, LS Building 64, Room 1070, 10903 New Hampshire Ave, Silver Spring, Maryland, 20993 002, USA.
authors.forename: Akhtar
authors.initials: A
authors.lastname: Siddiqui
authors.affiliation: Center for Drug Evaluation and Research, Office of Testing and Research, Division of Product Quality Research, Food and Drug Administration, White Oak, LS Building 64, Room 1070, 10903 New Hampshire Ave, Silver Spring, Maryland, 20993 002, USA. Mansoor.Khan@fda.hhs.gov.
authors.forename: Mansoor A
authors.initials: MA
authors.lastname: Khan
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods; D003460:Crystallization / Q000379:methods; D016018:Least-Squares Analysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009553:Nimodipine / Q000737:chemistry*; D033362:Powder Diffraction / Q000379:methods*; D011208:Powders / Q000737:chemistry*; D025341:Principal Component Analysis / Q000379:methods; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D011208:Powders; D014867:Water; D009553:Nimodipine
keywords: X-ray powder diffraction; multivariate; nimodipine polymorphs; solid-state nuclear magnetic resonance; univariate