Designing hydrogels for controlled drug delivery remains a big challenge. We developed a calcium polyphosphate hydrogel (CPP) as matrix for delivery of vancomycin (VCM) and erythromycin (EM) by unique ionic binding and physical wrapping. In this continuing study, we investigated if gel discs prepared by mechanical compaction (at 3000 psi pressure, C-discs) is superior to that of discs prepared by regular manual compaction (M-discs) for the release of VCM and EM (10 wt.%). Data demonstrated a significant reduction of burst release of VCM and EM in C-discs (1.8% and 5%, respectively) as compared to that from M-discs within 72 hr (55% and 60%, respectively, p < 0.05). In addition, C-discs significantly extended the VCM release (1500 hr) and EM (800 hr) as compared to M-discs (160 and 96 hr, respectively, p < 0.05). The VCM released from C-discs retained its bactericidal activity much longer (1500 hr) than that from M-discs (700 hr, p < 0.05). Raman Spectroscopy indicated an ionic bond of both VCM and EM with fully hydrated polyphosphate chains of CPP hydrogel matrix for both M-discs and C-discs. Micro CT showed that C-discs had much denser microstructures and less number/depth of microcracks as a result of high pressure. We propose that CPP hydrogel represents an excellent tool for the controllable and sustained delivery of VCM and EM. Extensive experiments are currently underway to evaluate the potential impacts of the modification of compaction techniques, other antibiotics, gel concentrations on the drug release, degradation behavior and infection control both in vitro and in vivo.

中文翻译：

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压实方法对从聚磷酸钙水凝胶基质中递送红霉素和万古霉素的影响

设计用于受控药物输送的水凝胶仍然是一个巨大的挑战。我们开发了一种多磷酸钙水凝胶 (CPP) 作为基质，通过独特的离子结合和物理包裹来递送万古霉素 (VCM) 和红霉素 (EM)。在这项持续研究中，我们调查了通过机械压实（在 3000 psi 压力下，C 盘）制备的凝胶盘是否优于通过常规手动压实（M 盘）制备的用于释放 VCM 和 EM（10 wt .%）。数据表明，与 M 盘相比，C 盘中 VCM 和 EM 在 72 小时内的突发释放显着减少（分别为 1.8% 和 5%）（分别为 55% 和 60%，p  < 0.05）。此外，与 M 盘（分别为 160 和 96 小时）相比，C 盘显着延长了 VCM 释放（1500 小时）和 EM（800 小时），p  < 0.05)。从 C 盘释放的 VCM 保持其杀菌活性的时间（1500 小时）比从 M 盘释放的（700 小时，p  < 0.05）长得多。拉曼光谱表明 VCM 和 EM 均与 M 盘和 C 盘的完全水合的 CPP 水凝胶基质的聚磷酸链形成离子键。显微 CT 表明，由于高压，C 盘的微观结构更致密，微裂纹的数量/深度更少。我们建议 CPP 水凝胶代表了 VCM 和 EM 的可控和持续交付的优秀工具。目前正在进行广泛的实验，以评估修改压实技术、其他抗生素、凝胶浓度对药物释放、降解行为和体外和体内感染控制的潜在影响。