To overcome the issue of multidrug resistant (MDR) microbes, the exploration of ways to improve the antimicrobial efficiency of existing antibiotics is one of the promising approaches. In search of synthons with higher efficiency, in current investigations, cocrystal and amorphous salt of levofloxacin hemihydrate (LEV) were developed with phthalimide (PTH) and caffeic acid (CFA). New materials were characterized with the help of FT-IR, Raman spectroscopy, powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Shifting, attenuation, appearance/disappearance and broadening of bands were observed in the FT-IR and Raman spectra of the materials as evidence of the required product. The PXRD diffraction pattern observed for LEV-PTH indicated cocrystal while halo diffractogram of LEV-CFA revealed amorphous nature. DSC/TG analysis confirmed the hydrated nature of the cocrystal/salt. The dissolution rate and antimicrobial activity against selected strains, K.pneumonia, E. coli and S. typhi of parent drug and the new material were compared. The zone of inhibition (ZI) observed for 5 µg LEV-PTH was 30.4 + 0.36 (K. pneumonia), 26.33 + 0.35 (E. coli) and 30.03 + 0.25 mm (S. typhi) while LEV-CFA salt (5 µg) against the same strains inhibited 33.96 ± 0.25, 31.66 ± 0.35 and 27.93 ± 0.40 mm, respectively. These novel formulations enhance the dissolution rate as well as antibacterial efficiency and are expected to be potent against MDR bacterial strains.

A series of N-pivaloyl-N′-(alkyl/aryl)-N′′-pyridylguanidine of general formula C₄H₉CONHC(NR¹R²)NPy have been synthesized and characterized using elemental analysis, FT-IR, multinuclear NMR spectroscopy, and in the case of compounds 7 and 11, by single crystal X-ray diffraction (XRD). The synthesized guanidines were tested for antitumor activities against potato tumor, and showed excellent inhibition against Agrobacterium tumefaciens (AT10)-induced tumor. The antioxidant and antimicrobial activities of these new compounds against various bacterial and fungal strains were also investigated.

The reaction of 1,3-Diisobutyl thiourea (Tu) with metal salts, {[CuX (X = Cl, I)], [ZnCl₂] and [HgI₂] in an appropriate stoichiometric ratio afforded the corresponding metal complexes [Tu₂CuCl] (1), [Tu₃CuI] (2), [Tu₂ZnCl₂] (3) and [Tu₂HgI₂] (4) in good yields. The FT-IR data show typically broad signals (3278–3288 cm⁻¹) attributed to the involvement of NH bonds in extensive hydrogen bonding. The structures of complexes were proposed based on a spectroscopic data set. Compounds 1 and 2 were additionally characterized by single-crystal X-ray analysis. Complexes 1–4 were tested for their free radical scavenging efficiency using 2,2-diphenyl-1-picrylhydrazyl free radical (hereafter abbreviated as DPPH). The free radical scavenging activity was a function of decrease in the resultant absorption of DPPH solution after the mixing of an appropriate concentration of the respective complex. The activity of complexes was determined to be dose dependent and increased concentration of the complex resulted in improved antioxidant activity. Compound 1 was found to be the most efficient, with 79.9% free radical scavenging activity. Complexes were also tested for their efficiency against selected strains of bacteria (E. coli, S. flexneri, S. typhi, and P. aeruginosa) and the activities were compared to commercially available standard drug cephradine. Compound 1 was more active against P.aeruginosa (ZI 13.25), while compound 4 was found to be more active against E. coli (ZI 11.0), S. flexneri (ZI 11.2), and S. typhi (ZI 10.5).

Reaction of the 1,3-diisobutyl thiourea (L) with MX [M = Cu, Ag and X = Cl, NO₃] provide polynuclear heteroleptic complexes [Cu₃L₃Cl₃] (1), [Ag₂L₆](NO₃)₂ (2) and [Ag₆L₈Cl₄] (3). All complexes were characterized by single crystal X-ray diffraction. The solid-state crystal of these complexes (1–3) were determined by single crystal XRD. Which shows that complex (1) is tri-nuclear with trigonal planer arrangement, complex (2) is binuclear with four membered metalacyclic ring and complex (3) is hexa-nuclear. Complexes (1–3) are tested for their free radical scavenging activity by using 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH) showing moderate potential.

Organochalcogen compounds have attracted the interest of a multitude of studies for their promising Pharmacological and biological activities. The antioxidant activity and acute toxicity of an organoselenium compound, 1-(2-(2-(2-(1-aminoethyl)phenyl)diselanyl)phenyl)ethanamine (APDP) was determined in mice. Mice were randomly divided into four groups, with each group comprising of seven animals. Canola oil (1ml/kg of body weight) was administered to 1st group, while 2nd, 3rd & 4th groups were administered with 10 mg/kg, 30 mg/kg & 350 mg/kg of APDP respectively. APDP was administered by Intragastric gavage as a single oral dose. The APDP oral administration was found to be safe up to 350 mg/kg of body weight and no deaths of animals were recorded. The lethal dose 50 (LD50) for APDP was determined at 72 h and was estimated to be > 350 mg/kg. After acute treatment, all mice were sacrificed by decapitation to determine the antioxidant enzymes and lipid peroxidation values for the treated mice liver. No fluctuation in lipid peroxidation, vitamin C and non protein thiol (NPSH) levels was observed due to the administration of APDP. hepatic α-ALA-D activity, catalase (CAT), superoxide dismutase (SOD) and the biochemical parameters were evaluated. Experimental observation demonstrated that APDP protected Fe(II) induced thiobarbituric acid reactive substances (TBARS) production in liver homogenate significantly (p < 0.05). The administration of APDP (an amine-based diselenide) both in vitro and in vivo clearly demonstrated that this potential compound has no acute toxicity towards mice among all the tested parameter. On the basis of experimental results, it is concluded that APDP is a potential candidate as an antioxidant compound for studying pharmacological properties.

Organic acids (3-chlorobenzoic acid and 4-chlorobenzoic acid) were treated with 4-amino-2-chloropyridine and 2-amino-4-chloropyridine as coformers for cocrystallization. Acid/base pairs afforded a cocrystal (3-chlorobenzoic acid and 4-amino-2-chloropyridine, compound 1) and molecular salts (2-amino-4-chloropyridinium 3-chlorobenzoate, 2; 2-amino-4-chloropyridinium 4-chlorobenzoate, 3). The products were characterized with the help of FT-IR, UV/visible spectroscopy, PXRD, and SC-XRD. The position of the Cl-substituent on the phenyl ring was explored with respect to proton transfer between acid/base pairs, and its role in supramolecular chemistry is discussed in detail. The existence of supramolecular assemblies was further reproduced using DFT calculations. Further, frontier molecular orbital (FMO), molecular electrostatic potential (MEP), and noncovalent interaction index (NCI) analyses were performed to gain insight into the electronic properties and nature of noncovalent interactions. The prepared compounds were examined for their biological activities against selected Gram-positive and Gram-negative bacterial strains and were also tested as antioxidant agents (DPPH free radical scavenging). Structural parameters determined experimentally and theoretically are within the expected range, and the biological activities of the resultant compounds are moderate.