School of Pharmacy, University of Hertfordshire, College Lane Hatfield AL10 9AB, UK.
J Control Release. 2010 Oct 15;147(2):289-97. doi: 10.1016/j.jconrel.2010.07.128. Epub 2010 Aug 10.
The cationic peptide, salmon calcitonin (sCT) was complexed with the cationic amphiphilic polyelectrolyte, poly(allyl)amine, grafted with palmitoyl and quaternary ammonium moieties at pH 5.0 and 7.4 to yield particulates (sCT-QPa). The complexes were approximately 200 nm in diameter, had zeta potentials ranging from +20 to +50 mV, and had narrow polydispersity indices (PDIs). Differential scanning calorimetry revealed the presence of an interaction between sCT and QPa in the complexes. Electron microscopy confirmed the zeta-size data and revealed a vesicular bilayer structure with an aqueous core. Tyrosine- and Nile red fluorescence indicated that the complexes retained gross physical stability for up to 7 days, but that the pH 5.0 complexes were more stable. The complexes were more resistant to peptidases, serum and liver homogenates compared to free sCT. In vitro bioactivity was measured by cAMP production in T47D cells and the complexes had EC50 values in the nM range. While free sCT was unable to generate cAMP following storage for 7 days, the complexes retained approximately 33% activity. When the complexes were injected intravenously to rats, free and complexed sCT (pH 5.0 and 7.4) but not QPa reduced serum calcium over 120 min. Free and complexed sCT but not QPa also reduced serum calcium over 240 min following intra-jejunal administration. In conclusion, sCT-QPa nanocomplexes that have been synthesised are stable, bioactive and resistant to a range of peptidases. These enhanced features suggest that they may have the potential for improved efficacy when formulated for injected and oral delivery.
阳离子肽，鲑鱼降钙素（sCT）与阳离子两亲性聚合物，棕榈酰和季铵化聚丙氨酸在 pH5.0 和 7.4 复合，生成颗粒（sCT-QPa）。复合物的直径约为 200nm，zeta 电位在+20 到+50mV 之间，且具有较窄的多分散指数（PDI）。差示扫描量热法表明复合物中 sCT 与 QPa 之间存在相互作用。电子显微镜证实了 zeta 尺寸数据，并显示出具有水性核的囊泡双层结构。酪氨酸和尼罗红荧光表明，复合物在长达 7 天的时间内保持了总体物理稳定性，但 pH5.0 复合物更稳定。与游离 sCT 相比，复合物对肽酶、血清和肝匀浆更具有抗性。通过 T47D 细胞中 cAMP 的产生来测量体外生物活性，复合物的 EC50 值在纳摩尔范围内。虽然游离 sCT 在储存 7 天后无法生成 cAMP，但复合物保留了约 33%的活性。当复合物经静脉注射到大鼠体内时，游离和复合 sCT（pH5.0 和 7.4）但不是 QPa 在 120 分钟内降低了血清钙。游离和复合 sCT 但不是 QPa 在十二指肠给药后 240 分钟内也降低了血清钙。总之，已合成的 sCT-QPa 纳米复合物具有稳定性、生物活性和对多种肽酶的抗性。这些增强的特性表明，它们在用于注射和口服给药的制剂中可能具有提高疗效的潜力。
