Journal of Applied Chemical Research
Year:2009 | Volume:10 | Issue:2|Papers Count:8

Sophisticated analytical methods viz. HPLC and HPTLC which being employed for analysis, are relatively expensive and hence need for simple analytical methods arises.One such method has been developed and applied for routine determination of acyclovir in pharmaceutical formulations and bulk dosage forms. The method is based on the formation of colored species via reaction of the enzyme horseradish peroxidase with Ferric chloride and 2, 2’- bipyridine in presence of orthophosphoric acid and finally with the drug to be estimated namely acyclovir to produce a pink colored chromogen (λmax at 400 nm).Statistical analysis of this method exhibited a molar absorptivity value 105 M-1 CM-1, and Sandell’s Sensitivity of 0.001912. RSD % of the method was found as 0.0386 indicating that the method is reproducible, based on the principle of absorption visible spectrophotometry for the determination of acyclovir in pharmaceutical formulations. The method is reliable and can be utilized for the determination of acyclovir in various pharmaceutical formulations and bulk dosage forms.

Nitrogen dc plasma is used to modify the red BS dye doped Poly (methyl methacrylate) (PMMA) polymer surface and results are compared. Samples are treated in dc plasma generated in a plane parallel electrode plasma reactor of 20W power for different times.The modified surfaces are characterized by Fourier Transform Infrared Spectrometery (ATR-FTIR) and atomic force microscoply (AFM). Using the results of contact angle measurement, polar and dispersion parts of surface energy are calculated. RMS roughness of sample surface is found to be changed noticeably by nitrogen plasma and the molecular structure of the treated surfaces is affected. The contribution of the polar part of surface energy is decreased with treatment time. The water contact angle is decreased noticeably by this treatment while transmittance and reflectance of samples in the range of 200 to 2000 nm are not changed.

The effect of doping in the new conjugated compounds based on thiophene and phenylene with the DFT method at UB3LYP level with 6-31G (d) basis set is theoretically studied.Attention is focused on the study of geometrical and electronic properties. It is shown that doping process modifies both bond length and torsion angles and electronic properties by enhancing the planarity and decreasing the band Gap. The results of this study demonstrate how the electronic properties can be tuned by doping and nominate these compounds as good candidates for opto-electronic applications.

Theoretical study on the geometries and electronic properties of new conjugated compound based on thiophene and oxadiazole was carried out. The theoretical ground-state geometry and electronic structure of the studied molecules were obtained by the DFT method at B3LYP level with 6-31G (d) basis set. The electronic properties were determined by ZINDO/s, CIS/6-31G (d) and TD//B3LYP/6-31G (d) calculations were performed on the B3LYP/6-31 (d) optimized geometries. The effects of the ring structure and the substituents on the geometries and electronic properties of these materials are discussed. The results of this study demonstrated how the electronic properties can be tuned by the backbone ring or side group and suggest these compounds as good candidates for opto-electronic applications.

The eigen values, eigen vector and population analysis of ferrocene and cobaltocene show that the first ten molecular orbitals in ferrocene and first seven in cobaltocene have contribution from 2pz orbitals of carbon of C5H5-and 3d orbitals of iron or cobalt. The extent of involvement of metal orbitals in the two cases are different. In ferrocene the maximum involvement out of 4s and 4p orbital is in the order 4pz > 4py> 4s> 4px and out of 3d orbitals the order of involvement is 3dyz > 3dxz > 3dz2 > 3dx2- y2 > 3dxy. The involvement of corresponding orbital in cobaltocene in respect of 4s and 4p orbitals is in the order 4s> 4pz> 4px and in 3d orbitals the order is 3dyz> 3dxy> 3dxz> 3dz2 > 3dx2-y2. The total involvement in respect of bonding between C5H5-and the metal orbitals as derived from coefficient values is 13.8 in ferrocene and 9.1 in cobaltocene. Comparison of eigen values indicate that ten most stable molecular orbitals have their energies in the range-0.4898 to-0.2314 eV in ferrocene and the seven most stable molecular orbitals in the range-0.4935 to-0.3583 eV in cobaltocene. The energies of first molecular orbital in ferrocene is-1.1084 eV and in cobaltocene-1.1027 eV. The population analysis shows that electrons from 2pz orbitals of carbon and 3d orbitals are provided in molecular orbital in both ferrocene and cobaltocene. The magnitude of contribution in the two cases differs significantly as the sum of the coefficient values of three 4p orbitals and five 3d orbitals in the ferrocene and cobaltocene are 13.8 and 9.1 respectively.

Ibuprofen sodium solution (a hydrotropic solubilizing additive) has been utilized to analyze two poorly water-soluble drugs; chlorpropamide (by titrimetric method) in the bulk drug and gatifloxacin (by spectrophotometric method) in tablet form. The results of analysis of chlorpropamide bulk drug were found to be very much close to the results of analysis by a standard method (British pharmacopoeial method) which proves the accuracy of proposed method. Low values of standard deviation, coefficient of variation and standard error have confirmed the validation of proposed method. In the case of gatifloxacin tablets, Beer’s law was obeyed in the concentration range of 10-60 mg/ml at 333 nm when ibuprofen sodium was used as a hydrotropic agent. Recovery studies and statistical data proved the accuracy, reproducibility and the precision of the proposed method. In both cases, the proposed methods did not involve use of organic solvents. Major drawbacks of organic solvents include high cost, volatility and toxicity. Safety of analyzer is also affected by toxicity of the solvent used. The proposed methods are new, simple, eco-friendly, cost-effective, accurate, safe and precise which can be successfully employed in the routine analysis of chlorpropamide bulk drug and gatifloxacin tablets. Ibuprofen sodium may also be tried for analysis of other poorly water-soluble drugs.

Antibacterial activity of various extracts of the fruit powder of Morinda citrifolia was studied against E coli, Staphylococcus aureus and Proteus vulgaris by cup plate method in nutrient agar medium. The activity was compared with standard levofloxacin under similar conditions. All the extracts of Morinda citrifolia were found to exhibit moderate antibacterial activity against S. aureus and Proteus vulgaris compared to standard levofloxacin.

Hydrazones possessing an azometine -NHN=CH- proton constitute an important class of compounds for new drug development. Therefore, many researchers have synthesized these compounds as target structures and evaluated their biological activities. These observations have been aimed for the development of new hydrazones that possess varied biological activities. In line with these observations, some new hydrazones were synthesized from hydrazides of neem, karanja and rice bran oils with a view to impart value addition to these non traditional oils. These newly synthesized compounds were characterized on the basis of elemental analysis and evaluated for biological properties. Certain hydrazones exhibited reasonable antibacterial and antifungal activities when compared with standards.