Capsaicin (trans-8-methyl-N-vanillyl-6-noneamide) is a hydrophobic, lipophilic vanilloid phytochemical abundantly found in chili peppers and pepper extracts. Several convergent studies show that capsaicin displays robust cancer activity, suppressing the growth, angiogenesis and metastasis of several human cancers. Despite its potent cancer-suppressing activity, the clinical applications of capsaicin as a viable anti-cancer drug have remained problematic due to its poor bioavailability and aqueous solubility properties. In addition, the administration of capsaicin is associated with adverse side effects like gastrointestinal cramps, stomach pain, nausea and diarrhea and vomiting. All these hurdles may be circumvented by encapsulation of capsaicin in sustained release drug delivery systems. Most of the capsaicin-based the sustained release drugs have been tested for their pain-relieving activity. Only a few of these formulations have been investigated as anti-cancer agents. The present review describes the physicochemical properties, bioavailability, and anti-cancer activity of capsaicin-sustained release agents. The asset of such continuous release capsaicin formulations is that they display better solubility, stability, bioavailability, and growth-suppressive activity than the free drug. The encapsulation of capsaicin in sustained release carriers minimizes the adverse side effects of capsaicin. In summary, these capsaicin-based sustained release drug delivery systems have the potential to function as novel chemotherapies, unique diagnostic imaging probes and innovative chemosensitization agents in human cancers.

Capsaicin (trans-8-methyl-N-vanillyl-6-noneamide) 是一种疏水性、亲脂性香草酸植物化学物质，广泛存在于辣椒和胡椒提取物中。多项综合研究表明，辣椒素具有强大的抗癌活性，可抑制多种人类癌症的生长、血管生成和转移。尽管辣椒素具有有效的抗癌活性，但由于其生物利用度和水溶性特性较差，辣椒素作为一种可行的抗癌药物的临床应用仍然存在问题。此外，服用辣椒素还会引起胃肠道痉挛、胃痛、恶心、腹泻和呕吐等不良副作用。所有这些障碍都可以通过将辣椒素封装在缓释药物递送系统中来克服。大多数基于辣椒素的缓释药物已经过其止痛活性测试。这些制剂中只有少数被研究作为抗癌剂。本综述描述了辣椒素缓释剂的理化性质、生物利用度和抗癌活性。这种连续释放辣椒素制剂的优点是它们比游离药物表现出更好的溶解度、稳定性、生物利用度和生长抑制活性。将辣椒素封装在缓释载体中可最大限度地减少辣椒素的不良副作用。总之，这些基于辣椒素的缓释药物递送系统有潜力作为人类癌症的新型化疗、独特的诊断成像探针和创新的化学增敏剂。