Solid oral controlled release formulations feature numerous clinical advantages for drug candidates with adequate solubility and dissolution rate.However,most new chemical entities exhibit poor water solubility,and hence are exempt from such benefits.Although combining drug amorphization with controlled release formulation is promising to elevate drug solubility,like other supersaturating systems,the problem of drug recrystallization has yet to be resolved,particularly within the dosage form.Here,we explored the potential of an emerging,non-leachable terpolymer nanoparticle(TPN)pore former as an internal recrystallization inhibitor within controlled release amorphous solid dispersion(CRASD)beads comprising a poorly soluble drug(celecoxib)reservoir and insoluble polymer(ethylcellulose)membrane.Compared to conventional pore former,polyvinylpyrrolidone(PVP),TPN-containing membranes exhibited superior structural integrity,less crystal formation at the CRASD bead surface,and greater extent of celecoxib release.All-atom molecular dynamics analyses revealed that in the presence of TPN,intra-molecular bonding,crystal formation tendency,diffusion coefficient,and molecular flexibility of celecoxib were reduced,while intermolecular H-bonding was increased as compared to PVP.This work suggests that selection of a pore former that promotes prolonged molecular separation within a nanoporous controlled release membrane structure may serve as an effective strategy to enhance amorphicity preservation inside CRASD.
Jamie Anne Lugtu-PeXuning ZhangSako MirzaieHao Han R.ChangNour AL-MousawiKuan ChenYongqiang LiAnil KaneDaniel Bar-ShalomXiao Yu Wu
基于纳米抗体(nanobody,Nb)和磁小体(bacterial magnetic particles,BMPs)的免疫磁珠在污染物分离分析中具有良好的应用前景,然而,不同长度柔性连接肽(linker)对免疫磁珠性能的影响尚未见相关报道。为了探究柔性连接肽长度对免疫磁珠的性能影响,本研究使用pET-28a作为载体,在磺胺间二甲氧嘧啶(sulfadimethoxine,SDM)Nb基因上融合了不同长度的柔性连接肽,分别为pET28a-SDM-Nb-(G4S)1-Cys和pET28a-SDM-Nb-(G4S)4-Cys,并使用大肠杆菌BL21(DE3)作为重组工程菌进行表达,最终获得Nb-(G4S)1-Cys和Nb-(G4S)4-Cys重组蛋白质。利用异源双功能试剂3-(2-吡啶二巯基)丙酸N-羟基琥珀酰亚胺酯(N-succinimidyl-3-(2-pyridyldithiol)propionate,SPDP),分别将重组蛋白质与BMPs进行偶联,构建了免疫磁珠。利用免疫印迹对偶联结果进行了初步鉴定,并对偶联条件进行了优化。同时,使用透射电镜和Zeta电位分析仪对免疫磁珠的水合粒径、Zeta电位和分散性进行了分析。研究结果表明,SPDP能有效地将Nb-(G4S)1-Cys和Nb-(G4S)4-Cys定向固定在BMPs表面。通过差值法计算发现,Nb-(G4S)1-Cys与BMPs的偶联效率高于Nb-(G4S)4-Cys与BMPs的偶联效率。进一步表征结果显示,BMP-(G4S)1-Nb的Zeta电位绝对值更高,水合粒径更小,并且具有较低的多分散性指数,说明其在水相体系中具有更强的胶体稳定性。综上所述,利用BMPs和Nb-(G4S)1-Cys构建的免疫磁珠性能优于BMPs和Nb-(G4S)4-Cys构建的免疫磁珠。这为今后选择合适长度的连接肽构建高效的免疫磁珠分离分析SDM提供了理论依据。
