Biodegradable nanoparticles have been well studied as biocompatible delivery systems. Nanoparticles of less than 200 nm in size can facilitate the passive targeting of drugs to tumour tissues and their accumulation therein via the enhanced permeability and retention (EPR) effect. Recent studies have focused on stimuli-responsive drug delivery systems (DDS) for improving the effectiveness of chemotherapy; for example, pH-sensitive DDS depend on the weakly acidic and neutral extracellular pH of tumour and normal tissues, respectively. In our previous work, core–shell nanoparticles composed of the biodegradable polymer poly(lactic acid) (PLA) and the widely used inorganic biomaterial hydroxyapatite (HAp, which exhibits pH sensitivity) were prepared using a surfactant-free method. These PLA/HAp core–shell nanoparticles could load 750 wt% of a hydrophobic model drug. In this work, the properties of the PLA/HAp core–shell nanoparticles loaded with the anti-cancer drug paclitaxel (PTX) were thoroughly investigated in vitro. Because the PTX-containing nanoparticles were approximately 80 nm in size, they can be expected to facilitate efficient drug delivery via the EPR effect. The core–shell nanoparticles were cytotoxic towards cancer cells (4T1). This was due to the pH sensitivity of the HAp shell, which is stable in neutral conditions and dissolves in acidic conditions. The cytotoxic activity of the PTX-loaded nanoparticles was sustained for up to 48 h, which was suitable for tumour growth inhibition. These results suggest that the core–shell nanoparticles can be suitable drug carriers for various water-insoluble drugs.

作为生物相容性递送系统，已经对可生物降解的纳米颗粒进行了充分的研究。尺寸小于200 nm的纳米颗粒可通过增强的渗透性和保留（EPR）效应，促进药物对肿瘤组织的被动靶向及其在肿瘤组织中的积累。最近的研究集中在刺激反应性药物递送系统（DDS）上，以提高化学疗法的有效性。例如，pH敏感的DDS分别取决于肿瘤和正常组织的弱酸性和中性细胞外pH。在我们以前的工作中，使用无表面活性剂的方法制备了由可生物降解的聚合物聚乳酸（PLA）和广泛使用的无机生物材料羟基磷灰石（HAp，具有pH敏感性）组成的核-壳纳米颗粒。这些PLA / HAp核壳纳米颗粒可以负载750 wt％的疏水模型药物。在这项工作中，彻底研究了负载有抗癌药紫杉醇（PTX）的PLA / HAp核壳纳米粒子的性能体外。由于含PTX的纳米颗粒的尺寸约为80 nm，因此可以预期它们将通过EPR效应促进有效的药物递送。核壳纳米粒子对癌细胞具有细胞毒性（4T1）。这是由于HAp外壳的pH敏感性，它在中性条件下稳定并在酸性条件下溶解。负载PTX的纳米颗粒的细胞毒性活性可以持续长达48小时，这适于抑制肿瘤生长。这些结果表明，核-壳纳米粒子可以作为各种水不溶性药物的合适药物载体。