Department of Chemistry, University of Puerto Rico, Río Piedras, San Juan, Puerto Rico 00931, USA.
Crystallization Design Institute, Molecular Sciences Research Center, University of Puerto Rico, San Juan, Puerto Rico 00926, USA and Department of Biology, University of Puerto Rico, Río Piedras, San Juan, Puerto Rico 00931, USA.
J Mater Chem B. 2020 Mar 11;8(10):2155-2168. doi: 10.1039/c9tb01857c.
The hydrothermal reaction between bioactive metal (Ca2+, Zn2+, and Mg2+) salts and a clinically utilized bisphosphonate, alendronate (ALEN), promotes the formation of several materials denominated as bisphosphonate-based coordination complexes (BPCCs). The systematic exploration of the effect of three variables, M2+/ALEN molar ratio, temperature, and pH, on the reaction yielded an unprecedented number of materials of enough crystal quality for structural elucidation. Five crystal structures were unveiled by single crystal X-ray diffraction (ALEN-Ca forms I and II, ALEN-Zn forms I and II, and ALEN-Mg) and their solid-state properties revealed in tandem with other techniques. The dissolution of these BPCCs was tested and contrasted to that of the commercially employed generic form of Fosamax® Alendronate Sodium, using fasted-state simulated gastric fluid and phosphate-buffered saline solution. Quantification of ALEN content was performed by derivatization with Cu2+, which produced a soluble complex suitable for quantification. The results show that these materials present a pH-dependent degradation. Moreover, a phase inversion temperature (PIT) nano-emulsion method was applied to the synthesis of ALEN-Ca form II. Size distribution analysis demonstrated the efficiency of the PIT-nano-emulsion method to decrease the particle size of this BPCC from ∼60 μm to ∼438 d nm. The cytotoxicity of ALEN, ALEN-Ca form II (bulk crystals), and nano-Ca@ALEN (nanocrystals) against the MDA-MB-231 cell line was investigated. Nano-Ca@ALEN form II presents higher cytotoxicity effects than ALEN and ALEN-Ca form II (bulk crystals), showing inhibition of cell proliferation at 7.5 μM. These results provide evidence of the structure, stability, dissolution and cytotoxicity properties of ALEN-based BPCCs and pave the way for better formulation strategies for this drug through the design of nano-sized BPCCs for the treatment of bone-related diseases.
水热反应将生物活性金属（Ca2+、Zn2+ 和 Mg2+）盐与临床应用的双膦酸盐，阿仑膦酸钠（ALEN）结合，促进了几种被称为双膦酸盐配位配合物（BPCCs）的材料的形成。系统地探索了三个变量（M2+/ALEN 摩尔比、温度和 pH）对反应的影响，得到了足够数量的具有足够晶体质量的材料，可用于结构阐明。通过单晶 X 射线衍射揭示了五个晶体结构（ALEN-Ca 形式 I 和 II、ALEN-Zn 形式 I 和 II 以及 ALEN-Mg），并结合其他技术揭示了它们的固态性质。通过使用空腹模拟胃液和磷酸盐缓冲盐水溶液对这些 BPCCs 的溶解进行了测试，并与市售的 Fosamax® Alendronate Sodium 通用形式进行了对比。通过 Cu2+衍生化对 ALEN 含量进行定量，产生了一种适合定量的可溶性络合物。结果表明，这些材料具有 pH 依赖性降解。此外，还应用相转变温度（PIT）纳米乳液法合成 ALEN-Ca 形式 II。粒径分布分析表明，PIT-纳米乳液法可有效降低该 BPCC 的粒径，从约 60 μm 降至约 438 d nm。对 MDA-MB-231 细胞系进行了 ALEN、ALEN-Ca 形式 II（块状晶体）和纳米 Ca@ALEN（纳米晶体）的细胞毒性研究。纳米 Ca@ALEN 形式 II 比 ALEN 和 ALEN-Ca 形式 II（块状晶体）具有更高的细胞毒性作用，在 7.5 μM 时显示出抑制细胞增殖的作用。这些结果提供了 ALEN 基 BPCCs 的结构、稳定性、溶解和细胞毒性特性的证据，并为通过设计用于治疗骨相关疾病的纳米级 BPCCs 为该药物制定更好的配方策略铺平了道路。
