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Isocyanate terminated prepolymers were synthesised using poly(tetramethylene oxide) glycol of molecular weight 1 000 (PTMG1000) and poly(propylene oxide) glycol of molecular weight 1 000 (PPG1000) with tolylene‐2,4‐diisocyanate (TDI). The prepolymers were chain extended with N,N‐bis(2‐hydroxyethyl)isonicotinamide to form polyurethanes containing pyridine moieties. These polyurethanes were converted to cationomers by crosslinking with (a) 1,4‐dibromobutane to form short‐chain crosslinked polymers (SCCPs) and (b) bromine‐terminated prepolymers to form long‐chain crosslinked polymers (LCCPs). The cationomers were characterised by Fourier transform infrared spectroscopy, thermal and mechanical analysis. FTIR spectral results of SCCPs and LCCPs confirmed the quaternisation of heterocyclic nitrogen leading to crosslinking. Dynamic mechanical analysis showed better damping properties for LCCPs than SCCPs. The stress‐strain measurements showed higher elongation and lower tensile strength for LCCPs.

ABSTRACT:Casein-gra/t-poly(acrylonitrile) was synthesized using potassium persulphate as initiator. The effect of monomer concentration on the kinetic parameters such as percent grafting and grafting efficiency were studied. The composition of the graft was analysed using Infrared spectroscopy. The mechanical and thermal stability were also studied and compared with pure casein.

An alternative ion chromatographic method to the existing USP method for the determination of N-methylpyrrolidine (NMP) in cefepime hydrochloride is developed. The cefepime in solution behaves as a strong cation and gets retained in the analytical column, leading to reduction in column capacity and irreproducible retention time. The retained drug has to be removed with a special rinsing solution, followed by re-equilibration with the mobile phase. This process takes at least 3 to 4 h time for sample analysis. We used a silica-based cation exchange column with poly-butadiene-maleic acid functional group attached with an optimized mobile phase composition. The characteristic feature of this method is the short analysis time with a clear separation of NMP and the cationic drug molecule within a run-time of 30 min. The developed method overcomes the limitations of the USP method. This method describes the matrix elimination by choosing appropriate column and eluent condition. The method is tested for selectivity, linearity, limits of detection and quantification, accuracy, and precision and is suitable for continuous sample analysis.

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