title: Quantitative determination of amorphous cyclosporine in crystalline cyclosporine samples by Fourier transform infrared spectroscopy.
abstract: The purpose of this study is the development of a quantification method to detect the amount of amorphous cyclosporine using Fourier transform infrared (FTIR) spectroscopy. The mixing of different percentages of crystalline cyclosporine with amorphous cyclosporine was used to obtain a set of standards, composed of cyclosporine samples characterized by different percentages of amorphous cyclosporine. Using a wavelength range of 450-4,000 cm(-1), FTIR spectra were obtained from samples in potassium bromide pellets and then a partial least squares (PLS) model was exploited to correlate the features of the FTIR spectra with the percentage of amorphous cyclosporine in the samples. This model gave a standard error of estimate (SEE) of 0.3562, with an r value of 0.9971 and a standard error of prediction (SEP) of 0.4168, which derives from the cross validation function used to check the precision of the model. Statistical values reveal the applicability of the method to the quantitative determination of amorphous cyclosporine in crystalline cyclosporine samples.
authors.affiliation: Istituto di Chimica Organica, Alessandro Marchesini, Facoltà di Farmacia, Università degli Studi di Milano, via Venezian 21, 20133, Milano, Italia, Milan, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Bertacche
authors.forename: Elena
authors.initials: E
authors.lastname: Pini
authors.forename: Riccardo
authors.initials: R
authors.lastname: Stradi
authors.forename: Fabio
authors.initials: F
authors.lastname: Stratta
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods*; D003460:Crystallization; D016572:Cyclosporine / Q000032:analysis* / Q000737:chemistry; D004355:Drug Stability; D016018:Least-Squares Analysis; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D016572:Cyclosporine