1. Fast crystallization of organic glass formers
Tanja Gnutzmann, Klaus Rademann* and Franziska Emmerling*. Chem. Commun., 2012, 48, 1638–1640
Herein, we report an even faster conversion with crystallization rates three to four orders of magnitude higher than those reported by Zhu et al. for the surface-enhanced crystallization. In a pilot study, we investigated the crystallization of the organic compound nifedipine by time resolved Raman spectroscopy. Nifedipine (4-(2-nitrophenyl)-2,6-dimethyl-3,5-dicarbomethoxy-1,4-dihydro-pyridine,) is an antihypertensive and vasodilating drug of dihydropyridine type. This calcium channel blocker has been studied intensively as it forms one amorphous and at least three crystalline modiﬁcations. Amongst these are the thermodynamically most stable a- and the metastable b-modiﬁcation.
2. Electrochemically-driven and dynamic enhancement of drug metabolism vian cytochrome P450 microsomes on colloidal gold/graphene nanocomposites
Minghe Huang, Xuan Xu, Hao Yang and Songqin Liu*. RSC Adv., 2012, 2, 12844–12850
Ketoconazole is a known inhibitor of cytochrome P450-mediated nifedipine metabolism. Inhibition studies with varying concentrations of ketoconazole from 0 to 0.68 mM were performed by addition into the aerobic solution with constant nifedipine concentration. The current versus the ketoconazole concentration is shown in Fig. 5. Ketoconazole strongly inhibited nifedipine oxidation in human liver microsomes with an IC50 value of 0.23 mM which was similar to previously reported values.
3. Binding mechanisms of 1,4-dihydropyridine derivatives to L-type calcium channel Cav1.2: a molecular modeling study
Lei Xu, Dan Li, Li Tao, Yanling Yang, Youyong Li and Tingjun Hou*. Mol. BioSyst., 2016, 12, 379—390
The structures of (S)-amlodipine and nifedipine diﬀer at the hydrophobic portside site, and they have a long chain and a methyl group in the ortho position at the stern NH group, respectively. The predicted binding free energy for nifedipine is weaker than that for (S)-amlodipine by B3 kcal mol-1. According to in vitro calcium antagonist activity, the (S)-amlodipine is more potent than nifedipine, which is in accordance with our predictions. Based on the predicted binding mode, the bowsprit group of nifedipine points downward and is direct toward the channel wall in comparison with that of (S)-amlodipine.
4. Crystal growth rates and molecular dynamics of nifedipine
Tanja Gnutzmann, Robert Kahlau, Franziska Emmerling*. CrystEngComm, 2013, 15, 4062–4069
Among the compounds studied in this context, nifedipine (4-(2-nitrophenyl)-2,6-dimethyl-3,5-dicarbomethoxy-1,4-dihy- dropyridine) is known for its polymorphism and high crystallization rates. Nifedipine is a widely used antihypertensive and vasodilating drug of the dihydropyridine type. Nifedipine is perfectly suited for crystallization growth rate studies and has been intensively investigated using dielectric spectroscopy among other methods. Recently, we reported extremely high crystallization rates of nifedipine, starting from an amorphous film produced via evaporation of an acetone solution.