Acrylate terpolymer in fabrication of medicated skin patches

An acrylate based pressure sensitive adhesive (PSA) was synthesized to design a drug‐in‐adhesive (DIA) type transdermal therapeutic system (TTS) for nitroglycerin used in the treatment of angina pectoris. 2‐Ethylhexyl acrylate (EHA), methyl methacrylate (MMA) and acrylic acid (AA) were used to synthesize the PSA by free radical solution polymerization. The effects of reaction time, reaction temperature, initiator concentration and solvent on polymerization were studied. The synthesized terpolymer was characterized by ¹H‐NMR, FT‐IR, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC) and also evaluated for intrinsic viscosity, refractive index, peel strength, moisture uptake and skin irritation potential. The PSA was used to develop DIA type patches of nitroglycerin. The patches were cast using solvent evaporation technique and dried at controlled temperature. The patches were evaluated for thickness uniformity, weight variation, peel strength and moisture pick‐up. The percent drug content and in vitro drug release was determined by high pressure liquid chromatography (HPLC) method. On the basis of in vitro release profile, patches were selected for in vitro skin permeation studies. The developed formulation TP‐1 (K = 24.892 mcg/cm²/hr) followed zero‐order rate kinetics and showed better skin permeation rate in comparison to the marketed TTS (MTTS) (K = 17.413 mcg/cm²/hr). TP‐1 was subjected to stability testing for a period of 1 year according to ICH guidelines. The patches were found to be stable and an expiry date of 2 years was predicted with storage at 25 °C or below. Copyright © 2001 John Wiley & Sons, Ltd.     

Transition-metal complexes with hydrazides and hydrazones

Several new complexes of dioxomolybdenum(VI) of the general formula [MoO₂(L)S], whereL is the dianion of salicylaldehydep-hydroxybenzoylhydrazone andS denotes H₂O, MeOH, py, PPh₃, DMSO or DMF, were synthesized and characterized by elemental analysis, electronic UV-VIS and IR spectra, thermal analysis, molar conductivity and magnetic susceptibility measurements. Salicylaldehydep-hydroxybenzoylhydrazone participates in the coordination as a tridentate ligand with the ONO set of donor atoms. The complexes contain acis-MoO₂ group and are of octahedral geometry. Complexes of the MoO₂L type were also prepared by synthesis in CHCl₃ solution and by isothermal heating of [MoO₂(L)S] complexes. The MoO₂L complex synthesized in CHCl₃ solution has most probably a pentacoordinated structure while the complex obtained by isothermal heating of [MoO₂(L)S] has a polymeric hexacoordinated structure.The authors are grateful to the Serbian Republic Research Fund for financial support and to academician Prof. M. ui for his interest in this work.     

Role of surfacelet transform in diagnosing Alzheimer’s disease

Multidimensional Systems and Signal Processing - The clinical diagnosis of Alzheimer’s disease (AD) is based on the tedious questionnaire and prolonged tests, which require involvement of the...     

First enantioselective synthesis of vinyl oxiranes from aldehydes and ylides generated from allyl halides and chiral sulfides

Asymmetric allylidenation of aldehydes with sulfur ylides is possible with proper substitution of the initial sulfide, to avoid the [2,3] sigmatropic rearrangement of the unsaturated ylides. One-pot reaction of (2R,5R)-dimethylthiolane with allyl halides, aldehydes, and sodium hydroxide in tert-butyl alcohol affords vinyl oxiranes in good yields. Enantiomeric excesses up to 90% and trans selectivities have been achieved with methallyl-type halides.     

Experimental investigations of thermal stability of some morpholinecarbamic acid complexes of copper(II) and zinc(II)

Some new carbamates, viz. M(MorphcbmH)₂X₂ (MorphcbmH = morpholinecarbamic acid, M = Cu, X = Cl, ClO₄,NO₃; M = Zn, X = Cl, ClO₄, NO₃, CH₃COO and X₂ = SO₄), have been synthesized and investigated. Compounds were characterized by elemental analysis, molar conductance, FT infrared, fluorescence, NMR (¹H and ¹³C) and solution electronic absorption spectral studies. Room temperature field-dependent magnetic susceptibility measurements, PXRD spectral and cyclic voltametric studies were also conducted. Chelating bidentate mode of coordination of ligand, MorphcbmH with four coordination around metal ion has been proposed. Ligand and its compounds have also been studied using non-isothermal thermogravimetric analysis and differential scanning calorimetric analytical techniques which inferred formation of metal oxide/MCO₃ as final thermal decomposition products. Compounds were screened against the lipase enzyme for assaying their enzyme activity and were found to retard the lipase activity from 48.16 to 0.044 µmol mL^?1 min^?1.     

Structural Insights into Peptides Bound to the Surface of Silica Nanopores

The structure and surface functionalization of biologically relevant silica-based hybrid materials was investigated by 2D solid-state NMR techniques combined with dynamic nuclear polarization (DNP). This approach was applied to a model system of mesoporous silica, which was modified through in-pore grafting of small peptides by solid-phase peptide synthesis (SPPS). To prove the covalent binding of the peptides on the surface, DNP-enhanced solid-state NMR was used for the detection of ¹⁵N NMR signals in natural abundance. DNP-enhanced heterocorrelation experiments with frequency switched Lee–Goldburg homonuclear proton decoupling (¹H–¹³C and ¹H–¹⁵N CP MAS FSLG HETCOR) were performed to verify the primary structure and configuration of the synthesized peptides. ¹H FSLG spectra and ¹H-²⁹Si FSLG HETCOR correlation spectra were recorded to investigate the orientation of the amino acid residues with respect to the silica surface. The combination of these NMR techniques provides detailed insights into the structure of amino acid functionalized hybrid compounds and allows for the understanding for each synthesis step during the in-pore SPPS.