Biography:

Abstract:

New microbicidal polyamides with quaternary Ammonium salts were prepared by the reaction of 5-phenyl-1, 3, 4,-oxadiazole-2 thiol, 5-phenyl 1, 3, 4-oxadiazol-2-amine and 5-(4-chlorophenyl) 1, 3, 4- thiadiazole-2-thiol with ethyl chloroformate followed by polycondensation with polyoxypropylenetriamine T403. The polyamides were modified to yield ammonium salts. The intercalation of polymeric ammonium salts into montmorillonite was achieved through an ion exchange process between sodium cations in MMT and ammonium groups in the polymer. The polymers and nanocomposites were characterized with elemental analysis, Proton nuclear magnetic resonance (1HNMR), Fourier Transformed Infrared (FT-IR) spectra, X-ray diffraction (XRD), Thermal gravimetric analysis (TGA) and transmission electron microscope (TEM). The in vitro release behavior of 1, 3, 4, oxa (thia) diazoles was investigated in buffered aqueous solution at different pH values (2.3, 5.8 and 7.4). A slow release, was recorded from the nanocomposites whereas, the release reaches almost 100% from ammonium salts of polyamides. The antimicrobial activity of the polymers was studied against Gram�negative bacteria (Escherichia coli ATCC 8739, Aeromonashydrophila and Shegillasp), Gram-positive bacteria (Staphylococcus aureus, B.subtillus ATCC 6633), Yeast (C.albicans) and the filamentous fungi (Aspergillusniger)by well diffusion method. The polymers showed good or moderate antimicrobial activities. However, nanocomposites showed no antimicrobial effect. We have shown the intercalation of polyamide loaded 1,3,4 oxa (thia) diazoles into MMT and invitro release of 1, 3, 4 oxa (thia) diazoles from polyamide-MMT. one objective of this study was to investigate the effect of nanoclay (MMT) on the release of 1,3,4-oxa (thia) diazoles. The other objective was to investigate the antimicrobial activity. The results clearly revealed that the compounds loaded into clay (VII, VIII and IX) exhibit no in vitro antimicrobial activity against all tested microorganism and this was explained by ref 25 the nano-clay material that reduce the polymer porosity. Preliminary test for polyamide-MMT nanocomposites showed potential ability to protect experimental mice from bacterial infections Different concentrations of the most active antimicrobial compounds (VII and IX) were screened to detect their MICs and MBCs valuesagainst A.hydrophila (the most sensitive one). The obtained results showed that the MIC and MBC values of VII and IX were recorded at 12.5 and 25 mg / ml (MICs) and were 6.25 and 3.16 mg/ml (MBCs) respectively, however, Tetracycline which used as a standard antimicrobial drug needed lower concentration (0.012 and 0.0062 mg/ml) to give the same effect. In the same context 26was found that the MIC of tested substance (2.5 mg/ml) was higher than that of standard amphotericin B against A.hydrophila. The intercalation was achieved through an ion exchange process between sodium cations in MMT and ammonium groups attached to the polymers. XRD patterns show an increase in the d-spacing confirming the intercalation of polymers into the interlayer of MMT. FTIR , TEM and TGA have evidenced the presence of the polymer in the MMT interlayer confinement. The in vitro release study indicate that polyamide-MMT can be used as the sustained release of 1, 3, 4 oxa (thia) diazoles in oral administration. The polymers showed good or moderate antimicrobial activities. However, nanocomposites showed no antimicrobial effect.