Atorvastatin ascorbic acid cocrystal strategy to improve the safety and efficacy of atorvastatin

The study was aimed to investigate the effect of dissolution enhancement on the hypolipidemic effect and hepatotoxicity of the drug in hyperlipidemic rats. Atorvastatin ascorbic acid cocrystals were prepared by phase solution methods and characterized by Fourier transformation infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy, X-Ray powder diffraction. Results of characterization confirmed that atorvastatin ascorbic acid cocrystals exhibited particle size was 221 nm. In in vitro study, results of dissolution test showed that the release of atorvastatin was increased to 1.6 folds. From In vivo study results, it was observed that in atorvastatin ascorbic acid cocrystals treated rats, serum total cholesterol, triglycerides, liver transaminase levels were significantly decreased, and liver glutathione activity was increased. In conclusion, atorvastatin ascorbic acid cocrystals therapy exhibited less hepatotoxicity in presence of ascorbic acid when compared to atorvastatin alone therapy and also the efficacy of therapy was improved.

Molecular Structure, Spectral Investigations, Hydrogen Bonding Interactions and Reactivity-Property Relationship of Caffeine-Citric Acid Cocrystal by Experimental and DFT Approach

The pharmaceutical cocrystal of caffeine-citric acid (CAF-CA, Form II) has been studied to explore the presence of hydrogen bonding interactions and structure-reactivity-property relationship between the two constituents CAF and Citric acid. The cocrystal was prepared by slurry crystallization. Powder X-ray diffraction (PXRD) analysis was done to characterize CAF-CA cocrystal. Also, differential scanning calorimetry (DSC) confirmed the existence of CAF-CA cocrystal. The vibrational spectroscopic (FT-IR and FT-Raman) signatures and quantum chemical approach have been used as a strategy to get insights into structural and spectral features of CAF-CA cocrystal. There was a good correlation among the experimental and theoretical results of dimer of cocrystal, as this model is capable of covering all nearest possible interactions present in the crystal structure of cocrystal. The spectroscopic results confirmed that (O33-H34) mode forms an intramolecular (C25 = O28∙∙∙H34-O33), while (O26-H27) (O39-H40) and (O43-H44) groups form intermolecular hydrogen bonding (O26-H27∙∙∙N24-C22, O39-H40∙∙∙O52 = C51 and O43-H44∙∙∙O86 = C83) in cocrystal due to red shifting and increment in bond length. The quantum theory of atoms in molecules (QTAIM) analysis revealed (O88-H89∙∙∙O41) as strongest intermolecular hydrogen bonding interaction with interaction energy -12.4247 kcal mol-1 in CAF-CA cocrystal. The natural bond orbital analysis of the second-order theory of the Fock matrix highlighted the presence of strong interactions (N∙∙∙H and O∙∙∙H) in cocrystal. The HOMO-LUMO energy gap value shows that the CAF-CA cocrystal is more reactive, less stable and softer than CAF active pharmaceutical ingredients. The electrophilic and nucleophilic reactivities of atomic sites involved in intermolecular hydrogen bond interactions in cocrystal have been demonstrated by mapping electron density isosurfaces over electrostatic potential i.e. plotting molecular electrostatic potential (MESP) map. The molar refractivity value of cocrystal lies within the set range by Lipinski and hence it may be used as orally active form. The results show that the physicochemical properties of CAF-CA cocrystal are enhanced in comparison to CAF (API).

Thermodynamic Investigation of Carbamazepine-Saccharin Co-Crystal Polymorphs

Polymorphism in active pharmaceutical ingredients can be regarded as critical for the potential that crystal form can have on the quality, efficacy, and safety of the final drug product. The current contribution aims to characterize thermodynamic interrelationship of a dimorphic co-crystal, FI and FII, involving carbamazepine (CBZ) and saccharin (SAC) molecules. Supramolecular synthesis of CBZ-SAC FI and FII has been performed using thermokinetic methods and systematically characterized by differential scanning calorimetry, powder X-ray diffraction, solubility, and slurry measurements. According to the heat of fusion rule by Burger and Ramberger, FI (ΔH_fus = 121.1 J/g; melting point, 172.5°C) and FII (ΔH_fus = 110.3 J/g; melting point, 164.7°C) are monotropically related. The solubility and van't Hoff plot results suggest FI stable and FII metastable forms. This study reveals that CBZ-SAC co-crystal phases, FI or FII, could be stable to heat-induced stresses; however, FII converts to FI during solution-mediated transformation.