Preparation of stable colloidal suspensions of superdisintegrants via wet stirred media milling

Superdisintegrants are cross-linked polymers that can be used as dispersants for fast release of drug nanoparticles from nanocomposite microparticles during in vitro and in vivo dissolution. Currently avail- able superdisintegrant particles have average sizes of approximately 5-130 μm, which are too big for drug nanocomposite applications. Hence, production of stable superdisintegrant suspensions with less than 5 μm particles is desirable. Here, we explore the preparation of colloidal suspensions of anionic and nonionic superdisintegrants using a wet stirred media mill and assess their physical stability. Sodium starch glycolate （SSG） and crospovidone （CP） were selected as representative anionic and nonionic superdisintegrants, and hydroxypropyl cellulose （HPC） and sodium dodecyl sulfate （SDS） were used as a steric stabilizer and a wetting agent/stabilizer, respectively. Particle sizing, scanning electron microscopy, and zeta potential measurements were used to characterize the suspensions. Colloidal superdisintegrant suspensions were prepared reproducibly. The extensive particle breakage was attributed to the swelling-induced softening in water. SSG suspensions were stable even in the absence of stabilizers, whereas CP suspensions required HPC-SDS for minimizing particle aggregation. These findings were explained by the higher absolute （negative） zeta potential of the suspensions of the anionic superdisintegrant （SSG） as compared with those of the nonionic superdisintegrant （CP）.

Colorimetric Sensor for Detection of Tabun Mimic Diethyl Cyanophosphonate

Herein,a colorimetric chemosensor(probe 7)was designed and synthesized for sensing diethyl cyanophosphonate(DCNP),a Tabun nerve agent simulant.The sensitive,selective,fast response and photostable probe 7 in dimethylsulfoxide(DMSO)responded to DCNP at low concentrations with visual naked eye color change from pink to pale yellow and displayed unresponsive behaviour against various interferences except for copper ions,which can be differentiated by adding ethylene diamine where the yellow color persisted in the case of DCNP but turned to pink in the case of copper ions.Additionally,the yellow aqueous solution of probe 7 at pH 10 and 12 turned colorless against the response of DCNP.The limit of detection(LOD)of probe 7 was found to be 50 nmol/L in an aqueous basic solution at pH 10 for the detection of DCNP.The formation of the cyclized product was elucidated by 1H and 31P NMR nuclear magnetic resonance(1H NMR,31P NMR),Fourier transform infrared spectroscopy(FTIR),and high-resolution mass spectrometry(HRMS)analysis.The filter paper and silica plate loaded with probe 7 were fabricated for real-time and on-site detection of DCNP.