A new complexes of the type ML2 and M′L [where M=Cu(II), Co(II), and Ni(II) and M′= Zn(II), Cd(II) and Hg(II)]. L = 3-[(2-hydroxy-quinolin-3-ylmethylene)-amino]-2-phenyl-3H-quinazolin-4-one, (HQMAPQ) Schiff base have been synthesized and characterized by elemental analysis, magnetic susceptibility, molar conductance, IR,1H NMR, UV-Visible and ESR data. The studies indicate the HQMAPQ acts as doubly monodentate bridge for metal(II) ions and form mononuclear complexes. The complexes Ni(II), Co(II) and Cu(II) complexes are found to be octahedral, where as Zn(II), Cd(II) and Hg(II) complexes are four coordinated with tetrahedral geometry. The synthesized ligand and its metal(II) complexes were screened for their antimicrobial activity.

The Schiff base ligand 5-bromo-3-(((8-hydroxy-2-methylquinolin-7-yl)methylene)hydrazono)indolin-2-one (BHMQMHI) was prepared via condensation of 5-bromo-3-hydrazonoindolin-2-one and 7-formyl-8-hydroxy-2-methylquinoline and its Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) complexes have been synthesized and characterized by elemental analysis, conductance data, magnetic susceptibility measurements, IR, UV-Vis, mass spectrometry, 1H NMR, ESR, XRD, and thermal studies. By these spectral studies it is found that Co(II), Ni(II), and Cu(II) complexes have exhibited octahedral geometry whereas the Zn(II), Cd(II), and Hg(II) complexes have exhibited tetrahedral geometry. Potentiometric studies have been carried out on complexes of Schiff base (BHMQMHI) with Cu(II), Co(II), and Ni(II). Calvin-Bjerrum pH-titration technique as used by Irving and Rossotti has been applied to determine stability constants in mixed solvents at 25 ± 1°C. The present study reports the protonation constants of this ligand and stability constants of its metal complexes in dioxane-water (50%, v/v) mixtures. Metal-ligand stability constants fall in the order of Cu(II) > Co(II) > Ni(II) which is in agreement with those reported by Irving stability order. The Schiff base (BHMQMHI) and its metal complexes have been screened for their in vitro antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The DNA cleavage activities of all the complexes were studied by agarose gel electrophoresis method. In addition, the free ligand along with its complexes has been studied for their antioxidant activity.

A new complexes of the type ML, MʹL and M″L [where M=Cu(II), Co(II), Ni(II) and Mn(II), Mʹ=Fe(III) and M″=Zn(II), Cd(II) and Hg(II) and L=N1-[(1E)-1-(2-hydroxyphenyl)ethylidene]-2-oxo-2H-chromene- 3-carbohydrazide (HL)] Schiff base have been synthesized and characterized by elemental analysis, magnetic susceptibility, molar conductance, IR,1H NMR, UV-Visible and ESR data. The studies indicate the HL acts as doubly monodentate bridge for metal ions and form mononuclear complexes. The complexes Ni(II), Co(II), Cu(II) Mn(II) and Fe(III) complexes are found to be octahedral, where as Zn(II), Cd(II) and Hg(II) complexes are four coordinated with tetrahedral geometry. The synthesized ligand and its metal complexes were screened for their antimicrobial activity.

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A simple condensation of 3-amino-2-methylquinazoline-4-one with 2-hydroxy-1-naphthaldehyde produced new tridentate ONO donor Schiff base ligand with efficient yield. The structural characterization of ligand and its Cu(II), Ni(II), Co(II), Mn(II), Zn(II), and Cd(II) complexes were achieved by the aid of elemental analysis, spectral characterization such as (UV-visible, IR, NMR, mass, and ESR), and magnetic data. The analytical and spectroscopic studies suggest the octahedral geometries of Cu(II), Co(II), Ni(II) and Mn(II) complexes and tetrahedral geometry of Zn(II) and Cd(II) complexes with the tridentate ONO Schiff base ligand. Furthermore, the conclusions drawn from these studies afford further support to the mode of bonding discussed on the basis of their 3D molecular modeling studies by considering different bond lengths, bond angles, and bond distance. The ligand and its metal complexes evaluated for their antimicrobial activity against Staphylococcus aureus (MTCC number 7443), Bacillus subtilis (MTCC number 9878), Escherichia coli (MTCC number 1698), Aspergillus niger (MTCC number 281), and Aspergillus flavus (MTCC number 277). The MIC of these compounds was found to be most active at 10 μg/mL concentration in inhibiting the growth of the tested organisms. The DNA cleavage activity of all the complexes was studied by gel electrophoresis method.

Simple, sensitive, rapid and cost effective extraction spectrophotometric methods are described for the assay of mebeverine hydrochloride (MBH) in bulk samples and pharmaceutical formulations. These two methods (Bromophenol blue and Erichrome Black‐T) are based on the formation of chloroform soluble ion‐pair complexes of MBH with Bromophenol blue (BPB) and with Erichrome Black‐T (EBT), to form yellow and pink colored chromogen in a Glycine‐HCl buffer of pH 2.4 (BPB) and in a KCl‐HCl buffer of pH 1.4 (EBT) with absorbance maximum at 416 nm and at 524 nm for BPB and EBT respectively. The calibration graph is found to linear over 0.2–20 μg/mL (BPB) and 0.2–20 μg/mL (EBT), with molar absorptivity values of 1.8295 × 104 1 moL−1 cm−1 and 1.5896 × 104 1 moL−1 cm−1, respectively. The LOD (Limit of Detection) were found to be 0.090 μg/mL and 0.084 μg/mL and LOQ (Limit of Quantification) were 0.2997 μg/mL and 0.2730 μg/mL for the BPB and EBT method, respectively. The results of analysis for the two methods have been validated statistically and by recovery studies. The results are compared with those obtained with reported method. The proposed methods are simple, sensitive, accurate and suitable for quality control applications.

The present investigation describes two simple, sensitive and validated spectrophotometric methods for the determination of Cyclophosphamide (CP) in pure and formulated forms. The methods are mainly based on the formation of charge transfer (CT) complex, with the reagents 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) (Method A) and p-Chloranilic acid (PCA) (Method B), hence a stable, 1:1 stoichiometric complex was obtained, which shows orangeyellow and pink colors, respectively. The produced chromogens optical densities were measured at 352 and 522 nm, respectively. The Beer's law was tested in the range of 2-16 and 5-50 µg mL -1 . The optical characteristics such as molar absorptivity (ɛ), and Sandell's sensitivity values were calculated. Other analytical parameters like, Limit of Detection (LOD), Limit of Quantification (LOQ), accuracy and precisions were evaluated. The proposed methods were successfully applied for the determination of the CP in tablet formulation with higher accuracy, better recoveries and less than 2% relative standard deviation.

A gas chromatographic method has been developed and validated for the determination of memantine hydrochloride (MMT) in pure and pharmaceutical preparations. The detection was carried out using flame ionization detector. Separation was achieved on a DB-624 fused silica packed capillary column (30 m x 0.320 mm x 1.8 μm). Nitrogen was used as a carrier gas at a flow rate of 40 mL/min. The column temperature was maintained at 300°C while the temperature of injection port and detector were maintained at 270° and 300°C, respectively. Gabapentin (GPN) was used as an internal standard. The procedure gave a linear response over the concentration range of 0.5-3.5 mg/mL with sufficient reproducibility. The method has been applied successfully for the determination of MMT in pure and pharmaceutical formulations. The excipients present in the formulations did not interfere with the assay procedure. The recovery values were found to be in the range of 99.85-100.1% with RSD values less than 1%. The results obtained from this method were compared with the reference method (HPTLC) reported in literature and no significant difference was found statistically