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This report provides an in-depth analysis of gabapentin solid forms by the National Institute for Pharmaceutical Technology and Education (NIPTE) Stability Group. It includes the examination of multiple forms of gabapentin, focusing on the monohydrate and desolvate states, and interconversions during analysis. Key findings include the identification of Form III in milled samples and the detection of gabapentin lactam as a primary degradation product. SSNMR characterizations reveal the effects of recrystallization on the stability of various gabapentin forms, highlighting important implications for pharmaceutical sciences.
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National Institute for Pharmaceutical Technology and Education (NIPTE) Stability Group - Solid Form Characterization Eric Munson
Outline • Samples of Gabapentin Analyzed • Gabapentin - multiple forms • Gabapentin monohydrate/desolvate • Interconversion of forms upon analysis • Identification - Form III in milled samples • Gabapentin Lactam (primary degradation product)
Gabapentin as Received - SSNMR O 8 9 2 1 7 3 OH NH2 6 5 4 1H T1 = 134 s Tentative NMR Assignments 3 7 (6,8) 2 (5,9) Not shown: Carbon 1 at 179.5 ppm 4
Lot D Intensity (arbitrary units) Lot C Lot B Lot A Two-Theta (deg) SSNMR of Gabapentin Forms - Effects of Recrystallization
Lot D Intensity (arbitrary units) Lot C Lot B Lot A Two-Theta (deg) SSNMR of Gabapentin Forms - Effects of Recrystallization
SSNMR of Gabapentin Forms - Effects of Recrystallization Lot A, 20x Lot B, 20x Lot C, 10x Lot D, 20x
Effect of Grinding on Forms • Particles of bulk lactose monohydrate before processing • Lactose monohydrate cryoground for 60 minutes Crystalline Amorphous Crystalline
Lactose 1H T1 Relaxation Data - SSNMR Lubach, J. W.; Xu, D.; Segmuller, B. E., Munson, E. J. In Press J. Pharm. Sci. 2006.
Lactose 1H T1 Relaxation Data - SSNMR Lubach, J. W.; Xu, D.; Segmuller, B. E., Munson, E. J. In Press J. Pharm. Sci. 2006.
Gabapentin Relaxation Times Stability - High, Medium, Low