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Item Pharmaceutical cocrystals of Efavirenz: Towards the improvement of solubility, dissolution rate and stability(Elsevier Ltd, 2021) Gowda, B.H.J.; Nechipadappu, S.K.; Shankar, S.J.; Chavali, M.; Paul, K.; Ahmed, M.G.; Sanjana, A.; Shanthala, H.K.Efavirenz (EFV) is a Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTI) class of antiretroviral drug that is included in antiretroviral therapy to treat Human Immunodeficiency Virus (HIV) patients to increase the life-span by avoiding them to develop Acquired Immune Deficiency Syndrome (AIDS). One of the major drawbacks of EFV is its solubility in purified water (0.093 mg/L). In the present work, two cocrystals of EFV using tartaric acid (TAR) and adipic acid (ADP) as coformers that are Generally Recognized as Safe (GRAS) are reported. Both the EFV-TAR and EFV-ADP cocrystals were developed using slow solvent evaporation technique and further characterization of developed cocrystal structures was done by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimetry (DSC) and Powder x-ray diffraction (PXRD) techniques. The SEM photomicrographs indicated that the EFV-TAR cocrystals were in needle shape with smooth surface. Its length ranged from 100 to 300 μm. The EFV-ADP cocrystals were found to be flaky needle shape with rough surface bearing irregular edges whose length ranged about 50-400 μm. The FT-IR spectra of both developed cocrystals confirmed the formation of a hydrogen bond between EFV and coformers by indicating a notable shift in -C=O functional group. The DSC and PXRD studies were further confirmed the successful development of a novel crystalline form (Cocrystal). The solubility (25 ± 0.5 °C) of EFV-TAR and EFV-ADP cocrystals were found to be 163 and 107 μg/mL respectively, whereas pure EFV showed 94 μg/mL. The dissolution rate (37 ± 0.5 °C) of EFV-TAR and EFV-ADP cocrystals in 1% sodium lauryl sulphate (SLS) solution demonstrated 1.4 and 1.2 times increment respectively, compared to the pure EFV. The developed EFV-TAR and EFV-ADP cocrystals were found to stable for 6 months in ambient conditions (25 ± 2 °C, 60 ± 5% relative humidity). © 2021 Elsevier Ltd. All rights reserved.Item Cocrystals of Ethenzamide: Study of Structural and Physicochemical Properties(American Chemical Society service@acs.org, 2016) Hariprasad, V.M.; Nechipadappu, S.K.; Trivedi, D.R.Pharmaceutical cocrystals of an analgesic drug ethenzamide (ETZ) with various coformers, namely, gallic acid (GA), 2-nitrobenzoic acid (2NB), 3-nitrobenzoic acid (3NB), 2,4-dinitrobenzoic acid (DNB), and 3-toluic acid (3TA) were synthesized by the solvent evaporation method. All the cocrystals were characterized by various analytical techniques, and the crystal structures were determined by the single-crystal X-ray diffraction method (SCXRD). SCXRD analysis revealed that all the synthesized cocrystals were formed through a robust supramolecular acid-amide heterosynthon except the ethenzamide/gallic acid cocrystal, where molecules interacted through O-H···O hydrogen bond involving -OH of gallic acid and oxygen of amide group of the ETZ molecule. The physicochemical properties such as stability, hygroscopicity, and solubility studies of the ETZ-GA cocrystal were evaluated. It was found that the ETZ-GA cocrystal has a higher solubility (2-fold) than that of the pure ETZ drug molecule. Hygroscopic study of the ETZ-GA cocrystal revealed that synthesized cocrystal was non-hygroscopic at ?75% RH conditions. The ETZ-GA cocrystal found to be stable for a time period of four months at ambient temperature. © 2016 American Chemical Society.Item Pharmaceutical salts of ethionamide with GRAS counter ion donors to enhance the solubility(Elsevier B.V., 2017) Nechipadappu, S.K.; Trivedi, D.R.Pharmaceutical salts of BCS class II second line anti-tuberculosis drug ethionamide (ETH) with various counter ions namely, 2-chloro-4-nitrobenzoic acid (CNB), 2,6-dihydroxybenzoic acid (2,6HBA), 2,3-dihydroxybenzoic acid (2,3HBA) and 2,4-dinitrobenzoic acid (DNB) were synthesized by crystal engineering approach. All the synthesized salts were characterized by various spectroscopic (NMR, FT-IR,), thermal (DSC & TGA) and PXRD techniques. The crystal structure of the synthesized salts was determined by single-crystal X-ray diffraction techniques. All the reported salts, except ETH-2,3HBA exhibited charge assisted acid pyridine heterosynthon. In ETH-2,3HBA hydoxyl pyridine heterosynthon is observed. In ETH-CNB salt, both ionic and neutral acid pyridine heterosynthon were observed in the asymmetric unit. ETH-DNB salt consists of both partial and complete proton transfer from DNB to ETH in the asymmetric unit. All the synthesized salts were found to be non-hygroscopic at accelerated humid condition (~ 75% RH). Solubility experiment has been performed in purified water and in 0.1 N HCl (pH = 1) solution and found that the solubility of ETH-CNB salt was about eight-fold higher soluble than ETH in purified water. The solubility of synthesized salts follows the order of ETH < ETH-2,3HBA < ETH-2,6HBA < ETH-CNB in purified water. © 2016 Elsevier B.V.Item Cocrystal of nutraceutical sinapic acid with Active Pharmaceutical Ingredients ethenzamide and 2-chloro-4-Nitrobenzoic acid: Equilibrium solubility and stability study(Elsevier B.V., 2018) Nechipadappu, S.K.; Trivedi, D.R.Sinapic acid (SNP) is a nutraceutical compound of hydroxybenzoic acid derivative which possesses anti-oxidant, anti-microbial, anti-inflammatory, anti-cancer, and anti-anxiety activity properties. In the present work, two cocrystals of SNP with two active drug ingredients such as Ethenzamide (ETZ) and 2-chloro-4-nitrobenzoic acid (CNB) are reported. Both the cocrystals were synthesized via simple solvent evaporation method and the crystal structures were characterized by Single Crystal X-ray Diffraction (SC-XRD) techniques. The cocrystals were formed via robust acid-amide heterosynthon and acid-acid homosynthon between SNP and drug molecules. Both the cocrystals were crystallized in monoclinic crystal system with P 21/c space group. The synthesized cocrystals were further characterized by DSC, PXRD, FT-IR, and 1H NMR techniques. The solubility study in purified distilled water and in 0.1 N HCl solution demonstrate that there was no increment in the solubility of drug molecules in the cocrystals in both purified water and in 0.1 N HCl solution. The synthesized cocrystal exhibited six months stability at ambient conditions (?25 °C, 60–65% RH). © 2018 Elsevier B.V.