Thermal methods for evaluating polymorphic transitions in nifedipine

3D printing of tablets containing multiple drugs with defined release profiles

“…From visual inspection of the data, all as-received materials exhibit multiple Bragg peaks in their XRPD patterns and are therefore crystalline. The patterns match well with those reported in the literature (Kadin, 1982;Grooff et al, 2007;Singh et al, 2014). After formulation and printing, the Bragg peaks for nifedipine and captopril are still present, with extra peaks observed from the excipients.…”

An Investigation of Nifedipine Miscibility in Solid Dispersions Using Raman Spectroscopy

“…am-NIF showed a T g at 45°C followed by exothermic crystallization to a metastable form at 96°C, which was then exothermically transformed to α-NIF at 119°C followed by melting at 170°C. This corresponds to the values reported by Grooff et al (25,32). The T g of Soluplus® was observed at 76°C.…”

Preparation and Transformation of True Nifedipine Polymorphs: Investigated with Differential Scanning Calorimetry and X-Ray Diffraction Pattern Fitting Methods

“…2a) confirmed the high amorphous crystallisation tendency from the observation of a crystallisation exotherm at approximately 90 • C. We reported in a previous paper that nifedipine crystallised to a metastable form B [melting temperature (T m,B ) 161 • C −163 • C, estimated enthalpy of fusion ∼70 J/g] 13 which transformed on further heating (∼120 • C-152 • C) to the stable crystalline form A. 13 The forms B and A polymorphs can from the heat of fusion rule by Burger and Ramberger 17 be labelled as monotropes. The thermodynamic stability relationship of the form B and A polymorphs, calculated according to the method of Yu 18 , further assumed a zero heat capacity difference between them.…”

“…The metastable crystal modification was prepared from DSC heating an amorphous modification at 10 • C/min to approximately 111 • C (this temperature on DSC thermogram showed the amorphous crystallisation event completed), followed by cooling on a metal block. 13 For the humidity effect study (samples stored at 22 • C), samples were analysed by DSC from −50 • C to 190 • C at a heat rate of 4 • C/min.…”