@article { ISI:000380968200060, title = {Syringic acid: structural elucidation and co-crystallization}, journal = {Crystal Growth \& Design}, volume = {16}, number = {8}, year = {2016}, month = {AUG}, pages = {4679-4687}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Syringic acid (SYRA) is a potential antioxidant used in traditional Chinese medicine and is an emerging nutraceutical. Current reports claim its potential anti-angiogenic, anti-glycating, anti-hyperglycaemic, neuroprotective, and memory-enhancing properties in various animal models. To date, SYRA crystal structure has not been elucidated, and no crystal engineering studies have been reported. This study reports the crystal structure of SYRA for the first time along with its nicotinamide (SNCT-E) and urea (SU-EA-M) co-crystals. All forms were successfully characterized using single crystal X-ray diffraction (XRD), powder XRD, and differential scanning calorimetry. Single crystal analysis revealed that SYRA crystallized in the C2/c space group, whereas SNCT-E (2:1) and SU-EA-M (1:2) crystallized in the P21/n and Cmca space group, respectively. Novel co-crystals have shown improved solubility, modified dissolution profiles, and improved flow and compressibility. Cytotoxic effects were explored in DU145 prostate cancer cell lines for the first time, and significant enhancement in cytotoxicity by the co-crystals was observed compared to plain components. A two-fold increase in \% cytotoxicity of SNCT-E was observed when compared to the corresponding physical mixture. These studies shed light on potential utility of SYRA as a coformer for various pharmaceutical applications to design synergistic and organ-protective co-crystals.

}, issn = {1528-7483}, doi = {10.1021/acs.cgd.6b00750}, author = {Thipparaboina, Rajesh and Mittapalli, Sudhir and Thatikonda, Sowjanya and Nangia, Ashwini and Naidu, V. G. M. and Shastri, Nalini R.} } @article {44190, title = {Rufinamide: crystal structure elucidation and solid state characterization}, journal = {Journal of Pharmaceutical and Biomedical Analysis}, volume = {149}, year = {2018}, month = {FEB}, pages = {185-192}, type = {Article}, abstract = {

Rufinamide (R) is a triazole derivative approved for the management of partial seizures and seizures associated with Lennox-Gastaut Syndrome, in November 2007. Crystal structure, solid state characterization, drug-excipient compatibility and solubility play a pivotal role in formulation development. This work deals with the crystal structure elucidation of R by single crystal X-ray diffraction and solid state characterization by thermal, spectroscopic and crystallographic techniques. Drug- excipient compatibility was assessed by differential scanning calorimetry (DSC). New RP-HPLC method for quantification of R was developed with improved retention time. Solubility and dissolution of drug in different media was determined. Additionally, the flow behavior of the drug was evaluated by measuring Carr{\textquoteright}s index and Hausner{\textquoteright}s ratio, while the compressibility behavior was studied using Well{\textquoteright}s protocol. R crystallized from dimethylformamide (R-DMF) was utilized for single crystal analysis. The drug crystallized in triclinic crystal system with P-1 space group. Asymmetric unit cell consists of two molecules of R held by intermolecular hydrogen bond (connected by N-H center dot center dot center dot O, which forms the catemeric chain). Analytical outcomes from DSC, thermogravimetric analysis (TGA) and powder X-ray diffraction (PXRD) revealed that the drug was present in pure crystalline form and was devoid of any polymorphic or pseudopolymorphic impurities. Influence of pH on the solubility and dissolution of R-DMF was found to be insignificant. The drug exhibited poor aqueous solubility, which was improved nearly 4.6 fold with the addition of 2\% sodium lauryl sulphate (SLS). The drug exhibits poor flow and elastic compression nature. Excipients such as poly ethylene glycol (PEG) 8000, SLS, lactose monohydrate, starch and Hydroxypropyl methylcellulose (HPMC) E15 were incompatible with R-DMF as identified by thermal analysis. It is envisaged that these information regarding solid state properties of R-DMF would aid in identifying a logical path for formulation development. (C) 2017 Elsevier B.V. All rights reserved.

}, keywords = {Compressibility, Dissolution media, DSC, HPLC method, solubility}, issn = {0731-7085}, doi = {10.1016/j.jpba.2017.11.003}, author = {Salunke, Nita and Thipparaboina, Rajesh and Chavan, Rahul B. and Lodagekar, Anurag and Mittapalli, Sudhir and Nangia, Ashwini and Shastri, Nalini R.} } @article {46268, title = {Co amorphous valsartan nifedipine system: Preparation, characterization, in vitro and in vivo evaluation}, journal = {European Journal of Pharmaceutical Sciences}, volume = {139}, year = {2019}, month = {NOV}, type = {Article}, abstract = {

Co amorphous systems are supersaturated drug delivery systems which offer a basic platform for delivery of multicomponent adducts (combination of more than one active pharmaceutical ingredient (API)) and/or as a fixed dose combination therapy, in addition to their potential to improve the apparent solubility, dissolution rate and ultimately bioavailability of poorly water soluble APIs. In the present work, a new drug-drug co amorphous system namely valsartan-nifedipine was prepared by quench cooling technique. Prepared co amorphous system was characterized for its solid state behavior with the help of Fourier Transform Infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Powder X Ray Diffractometry (PXRD). The optimized co amorphous system was stable for 1 month when exposed to accelerated stability condition (40 +/- 2 degrees C and 75 +/- 5\% RH). The improved stability of amorphous nifedipine in co amorphous system was attributed to improved miscibility and intra and intermolecular non-covalent interactions mainly due to presence of hydrogen bonding between valsartan and nifedipine which was studied by FTIR analysis. Co amorphous systems were evaluated by mainly in vitro dissolution and in vivo benefit. In vitro dissolution study showed nearly 5.66 folds and 1.61 folds improvement which was translated to 3.63 and 2.19 times enhancement in vivo C-max for nifedipine and valsartan respectively.

}, doi = {10.1016/j.ejps.2019.105048}, author = {Lodagekar, Anurag and Chavan, Rahul B. and Mannava, M. K. Chaitanya and Yadav, Balvant and Chella, Naveen and Nangia, Ashwini K. and Shastri, Nalini R.} } @article {46285, title = {Hepatoprotective cocrystals of isoniazid: synthesis, solid state characterization, and hepatotoxicity studies}, journal = {Crystal Growth \& Design}, volume = {19}, year = {2019}, month = {SEP}, pages = {5161-5172}, type = {Article}, abstract = {

Isoniazid (INH) is one of the first line drugs used in combination with pyrazinamide and rifampicin for the management of tuberculosis. Idiosyncratic hepatotoxicity is one of the most common side effects of antitubercular therapy worldwide. The current study explores solid phase modification of INH by cocrystallization with various hepatoprotective coformers, namely chrysin, hesperetin, silibinin, syringic acid (SYRA), and quercetin (QUE) to address hepatotoxicity concerns. Cocrystals were obtained with SYRA and QUE. Supramolecular synthons based on pyridine-carboxyl and pyridine-hydroxyl synthon enabled the formation of cocrystals. INHSYRA and INHQUE cocrystals were characterized by FT-IR, DSC, and PXRD. Single crystal X-ray analysis of INHSYRA revealed that it crystallized in triclinic system with the P (1) over bar space group. Intrinsic dissolution rate studies (IDR) showed slow drug release from both the cocrystals. Hepatoprotective effects of INHSYRA and INHQUE cocrystals were evaluated by a single toxic dose study and a subchronic study for 28 days. Results from the subchronic study indicated significant increase in ALT, AST, and ALP enzyme levels in the INH-treated group whereas the enzyme levels in INHSYRA and INHQUE cocrystal treated group were comparable to that of the untreated group. This study demonstrates the in vivo hepatoprotective effects of coformers SYRA and QUE provide promising evidence for utility of nutraceutical based coformers, to tackle hepatotoxicity associated with various drugs.

}, doi = {10.1021/acs.cgd.9b00541}, author = {Yadav, Balvant and Gunnam, Anilkumar and Thipparaboina, Rajesh and Nangia, Ashwini K. and Shastri, Nalini R.} } @article {46007, title = {Quantification of niclosamide polymorphic forms - a comparative study by Raman, NIR and MIR using chemometric techniques}, journal = {Talanta}, volume = {199}, year = {2019}, month = {JUL }, pages = {679-688}, type = {Article}, abstract = {

Niclosamide, an anthelmintic drug recently repurposed for its activity against cancer, crystallizes into three solvated forms, two monohydrates (NHa, NHb) and one anhydrous (NAn) form. NAn is sensitive to pseudopolymorphic transformations that affect its dissolution and consequently, its bioavailability. NAn exhibits a polymorphic conversion to metastable monohydrate (NHa) form during high-energy milling in presence of poorly soluble solvents like water. It is hence very important to quantify polymorphic conversion from NAn to NHa, as water is a commonly used solvent during various processing like ball milling and wet granulation. This main objective of the study was to examine the feasibility of Raman, NIR and MIR spectroscopic techniques for identification and quantification of polymorphic forms of niclosamide in binary mixtures and multicomponent mixtures. Calibration models were developed and validated by vibrational spectroscopic techniques in binary mixtures of NAn and NHa and in multicomponent mixtures by chemometric techniques. These techniques were further used to identify and quantify NHa during ball milling, granulation and in presence of other polymorphic forms of niclosamide. Identification and quantification of pseudopolymorphs in binary and multicomponent mixtures with an acceptable recovery of 100.13-102.99\% for Raman and 100.07-101.28\% for NIR with low \% RSD of 2.38-3.12 for both techniques were obtained. The \% NHa determined during ball milling and granulation was similar by NIR and Raman. Raman spectroscopy however showed a greater advantage over other techniques in determining the NHa in presence of NHb due to significant difference in the spectral region of hydrates, when compared to NIR and MIR.

}, keywords = {Ball milling, Granulation, MSC, PLS, Polymorphic conversion, spectroscopy}, issn = {0039-9140}, doi = {10.1016/j.talanta.2019.03.027}, author = {Bhavana, Valmala and Chavan, Rahul B. and Mannava, M. K. Chaitanya and Nangia, Ashwini and Shastri, Nalini R.} } @article {46835, title = {Generation and evaluation of pharmacologically relevant drug-drug cocrystal for gout therapy}, journal = {Crystal Growth \& Design}, volume = {20}, year = {2020}, month = {JUN }, pages = {3577-3583}, type = {Article}, abstract = {

The present study reports a novel drug-drug cocrystal of febuxostat and piroxicam for the treatment of gout. Single crystal X-ray diffraction revealed a monoclinic system with P2(1)/c space group. The prepared cocrystal enhanced the solubility of febuxostat and piroxicam and improved the dissolution rate of piroxicam in pH 6.8 as compared to the pure drug. Further, the compressibility assessment of cocrystal by Aulton and Wells method confirmed its plastic behavior and suitability for direct compression.

}, issn = {1528-7483}, doi = {10.1021/acs.cgd.0c00106}, author = {Modani, Sheela and Gunnam, Anilkumar and Yadav, Balvant and Nangia, Ashwini K. and Shastri, Nalini R.} } @article {47115, title = {Enhanced solubility, permeability, and tabletability of nicorandil by salt and cocrystal formation}, journal = {Crystengcomm}, volume = {23}, year = {2021}, month = {JAN }, pages = {227-237}, type = {Article}, abstract = {

Cocrystallization is a rational selection crystal engineering approach for the development of novel solid forms with enhanced physicochemical and mechanical properties. Nicorandil (NCR) is a niacinamide vitamin derivative used to treat angina pectoris. A binary solid form screen of NCR with homologous dicarboxylic acids afforded NCR-oxalic acid (NCR-OA, 1:1), NCR-fumaric acid (NCR-FA, 1:1), NCR-succinic acid (NCR-SA, 1:1), and NCR-suberic acid (NCR-SBA, 1:0.5). The binary solids were characterized by powder X-ray diffraction, IR and NMR spectroscopy, and DSC. NCR-FA and NCR-SBA were crystallized by slow evaporation from chloroform and toluene solvents, respectively. Single crystal X-ray diffraction confirmed that NCR-FA is a molecular salt, while NCR-SBA is a neutral cocrystal. NCR and the FA anion are connected via the robust carbovlate-pyridinium synthon, whereas in the NCR-SBA cocrystal, the components associate via the carboxylic acid- -pyridine synthon. The phase stability, solubility, dissolution rate, diffusion rate and tabletability studies have demonstrated that the binary solids exhibit improved physical and mechanical properties compared to the NCR drug. Specifically, the NCR-FA salt and NCR-SBA cocrystal have higher solubility, dissolution rate, and hardness at lower pressures, making the formulation suitable for tablet compression.

}, issn = {1466-8033}, doi = {10.1039/d0ce01316a}, author = {Mannava, M. K. Chaitanya and Gunnam, Anilkumar and Lodagekar, Anurag and Shastri, Nalini R. and Nangia, Ashwini K. and Solomon, K. Anand} } @article {47719, title = {The effects of cis and trans butenedioic acid on the physicochemical behavior of lumefantrine}, journal = {Crystengcomm}, volume = {24}, year = {2022}, month = {JAN }, pages = {156-168}, type = {Article}, abstract = {The present work investigates the effects of cis and trans butenedioic acid isomers (maleic acid and fumaric acid) on the crystallinity and pharmaceutical behavior of lumefantrine. Differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), attenuated total reflectance infrared spectroscopy (ATR-IR), solid-state nuclear magnetic resonance spectroscopy (ss-NMR), and single-crystal X-ray diffraction (SC-XRD) studies were employed. Lumefantrine-fumaric acid crystallized as a salt in the monoclinic space group P2(1)/c. In comparison, DSC and PXRD showed the formation of a co-amorphous solid with maleic acid. Complete proton transfer with a strong ionic interaction led to crystalline salt formation with the trans isomer, whereas weaker/fewer hydrogen bonds with the cis isomer of butenedioic acid led to a co-amorphous salt. The in vitro dissolution of both salts resulted in a similar 2.6-2.7-fold improvement in dissolution rate when compared to that of the crystalline lumefantrine. The crystalline and co-amorphous salts were stable under accelerated stability conditions (40 +/- 2 degrees C and 75 +/- 5\% RH) for one month.}, doi = {10.1039/d0ce01709d}, author = {Tomar, Devendrasingh and Lodagekar, Anurag and Gunnam, Anilkumar and Allu, Suryanarayana and Chavan, Rahul B. and Tharkar, Minakshi and Ajithkumar, T. G. and Nangia, Ashwini K. and Shastri, Nalini R.} }