TY - JOUR

T1 - Formation mechanism of coamorphous drug−amino acid mixtures

AU - Jensen, Katrine Birgitte Tarp

AU - Larsen, Flemming Hofmann

AU - Cornett, Claus

AU - Löbmann, Korbinian

AU - Grohganz, Holger

AU - Rades, Thomas

PY - 2015

Y1 - 2015

N2 - Two coamorphous drug−amino acid systems, indomethacin−tryptophan (Ind−Trp) and furosemide−tryptophan Fur−Trp), were analyzed toward their ease of amorphization and mechanism of coamorphization during ball milling. The two mixtures were compared to the corresponding amorphization of the pure drug without amino acid. Powder blends at a 1:1 molar ratio were milled for varying times, and their physicochemical properties were investigated using XRPD, 13C solid state NMR (ssNMR), and DSC. Comilling the drug with the amino acid reduced the milling time required to obtain an amorphous powder from more than 90 min in the case of the pure drugs to 30 min for the coamorphous powders. Amorphization was observed as reductions in XRPD reflections and was additionally quantified based on normalized principal component analysis (PCA) scores of the ssNMR spectra. Furthermore, the evolution in the glass temperature (Tg) of the coamorphous systems over time indicated complete coamorphization after 30 min of milling. Based on the DSC data it was possible to identify the formation mechanism of the two coamorphous systems. The Tg position of the samples suggested that coamorphous Ind−Trp was formed by the amino acid being dissolved in the amorphous drug, whereas coamorphous Fur−Trp was formed by the drug being dissolved in the amorphous amino acid.

AB - Two coamorphous drug−amino acid systems, indomethacin−tryptophan (Ind−Trp) and furosemide−tryptophan Fur−Trp), were analyzed toward their ease of amorphization and mechanism of coamorphization during ball milling. The two mixtures were compared to the corresponding amorphization of the pure drug without amino acid. Powder blends at a 1:1 molar ratio were milled for varying times, and their physicochemical properties were investigated using XRPD, 13C solid state NMR (ssNMR), and DSC. Comilling the drug with the amino acid reduced the milling time required to obtain an amorphous powder from more than 90 min in the case of the pure drugs to 30 min for the coamorphous powders. Amorphization was observed as reductions in XRPD reflections and was additionally quantified based on normalized principal component analysis (PCA) scores of the ssNMR spectra. Furthermore, the evolution in the glass temperature (Tg) of the coamorphous systems over time indicated complete coamorphization after 30 min of milling. Based on the DSC data it was possible to identify the formation mechanism of the two coamorphous systems. The Tg position of the samples suggested that coamorphous Ind−Trp was formed by the amino acid being dissolved in the amorphous drug, whereas coamorphous Fur−Trp was formed by the drug being dissolved in the amorphous amino acid.

U2 - 10.1021/acs.molpharmaceut.5b00295

DO - 10.1021/acs.molpharmaceut.5b00295

M3 - Journal article

C2 - 26057950

VL - 12

SP - 2484−2492

JO - Molecular Pharmaceutics

JF - Molecular Pharmaceutics

SN - 1543-8384

IS - 7

ER -