Photophysics of 1<i>H</i>-1,5-benzodiazepine in aqueous cyclodextrin environments

389-391The photophysics of 2, 3-dihydro-2,2,4-trimethyl-1 H-1,5-benzodiazepine (L) has been studied in aqueous cyclodextrin (CD) environments. Development of a new emission band for the CD-encapsulated moiety at the high energy side of the emission band in aqueous solution indicates that the fluorophore experiences a different microenvironment within the CD cavity, affecting the solvent-assisted excited state intramolecular proton transfer (SAESIPT) process. A difference in the relative enhancement of the blue emission compared to the other one has been rationalized on the basis of the size parameters of the fluorophore as well as the CD cavities

Formulation and Evaluation of Buccal Patches of Diclofenac Sodium as a Model Drug

The present study was concerned with the formulation and evaluation of buccal patches of Diclofenac Sodium. Here, Diclofenac sodium is used as a model drug. Buccal patches of Diclofenac Sodium were preparedby solvent casting method using PEG 400, Glutaraldehyde, Glycerin, HPMC, Gelatin and required quantity of distilled water. Weight variation, thickness, drug content and release studies were assessed. Keywords: Buccal patch, Diclofenac sodium, oral mucosa, HPMC, PEG-400, Glutaraldehyde

Kinetics of the photoconversion of diphenylamine in β-cyclodextrin environments

Photochemical conversion of diphenylamine (DPA) to carbazole (CAZL) has been studied fluorometrically in aerated aqueous and aqueous β-cyclodextrin (β-CD) environments. The fluorophore forms a 1:1 inclusion complex with β-CD. The quantum yield of the photoreaction is found to remain unaltered in both the environments. However, estimation of the rate constants for the photochemical conversion of DPA to CAZL in the two environments reveals that within the CD environment, rate of the photoreaction is affected remarkably. This has been rationalized from the restriction in the intramolecular rotation for accessing the reaction centres responsible for the photocyclization process. This has also been corroborated from a comparison of the cavity diameter of the β-CD and the optimized geometry of DPA obtained from the semiempirical (AM1-SCI) calculation

Photophysics of an 1<i>H</i>-1,5- benzodiazepine in some selected solvents

917-919Results of some preliminary steady state, time-resolved and theoretical studies on the photo physics of 2.3-dihydro-2,2,4 -trimethyl-1H-1,5-benzodiazepine (L), an anti-convulsant agent, are reported here, Although L is weakly fluorescing in all the solvents studied, its luminescence is highly solvent-sensitive. It seems that the protic solvents have an important role in the fluorescence behaviour of L. Participation of the methylene hydrogens in the solvent assisted proton transfer has been proposed

Effect of cyclodextrin encapsulation on the photocyclization of diphenylamine: Cavity imposed restriction on the reaction rate

The kinetics of the photocyclization of diphenylamine (DPA) to carbazole (CAZL) has been studied fluorometrically in air-equilibrated aqueous solution as well as in constrained microheterogeneous media provided by [alpha]-, [beta]-, and [gamma]- cyclodextrins (CDs). It is observed that the fluorophore is embedded within the CD cavities without any alteration of the overall reaction quantum yield in the different environments. However, the rate of the photoreaction is modified remarkably within the CD environments. A restriction on the intramolecular rotation of the phenyl planes of DPA, imposed by the steric rigidity within the CD cavities, has been ascribed to be responsible for the suppression of the reaction rates within the CD environments. A semi-empirical (AM1) calculation gives the molecular dimension of the substrate and corroborates the proposition from a consideration of the cavity size of the different cyclodextrins.http://www.sciencedirect.com/science/article/B6TGR-44WJT2F-D/1/fbeee114a055a066bec9406d2538f43