Locoregional drug delivery is a novel approach for the effective delivery of anti-cancer agents as it exposes the tumors to high concentration of drugs. In situ gelling systems have fetched paramount attention in the field of localized cancer chemotherapy due to their targeted delivery, ease of preparation, prolonged or sustained drug release and improved patient compliance. Numerous polymers have been investigated for their properties like swelling along with biodegradation, drug release and physicochemical properties for successful targeting of the drugs at the site of implantation. The polymers such as chitosan, Hyaluronic Acid (HA), poloxamer, Poly Glycolic Lactic Acid (PGLA) and Poly Lactic Acid (PLA) tend to form in situ hydrogels and have been exploited to develop localized delivery vehicles. These formulations are administered in the solution form and on exposure to physiological environment such as temperature, pH or ionic composition they undergo phase conversion into a hydrogel drug depot. The use of in situ gelling approach has provided prospects to increase overall survival and life quality of cancer patient by enhancing the bioavailability of drug to the site of tumor by minimizing the exposure to normal cells and alleviating systemic side effects. Because of its favorable safety profile and clinical benefits, United States Food and Drug Administration (U.S. FDA) has approved polymer based in situ systems for prolonged locoregional activity. This article discusses the rationale for developing in situ systems for targeted delivery of anti-cancer agents with special emphasis on types of polymers used to formulate the in situ system. In situ formulations for locoregional anti-cancer drug delivery that are marketed and are under clinical trials have also been discussed in detail in this article.

局部药物递送是有效递送抗癌剂的新方法，因为它使肿瘤暴露于高浓度的药物中。原位胶凝系统由于其靶向递送，易于制备，延长或持续的药物释放以及改善的患者依从性而在局部癌症化学疗法领域引起了极大关注。已经对许多聚合物的性质进行了研究，例如溶胀以及生物降解，药物释放和理化性质，以成功地将药物靶向到植入部位。聚合物，如壳聚糖，透明质酸（HA），泊洛沙姆，聚乙醇酸乳酸（PGLA）和聚乳酸（PLA）倾向于在原位形成水凝胶，并已被用于开发局部递送载体。这些制剂以溶液形式给药，并在暴露于诸如温度，pH或离子组合物的生理环境中时经历相转化为水凝胶药物贮库。原位胶凝方法的使用为通过减少对正常细胞的暴露和减轻全身性副作用来增强药物对肿瘤部位的生物利用度提供了提高癌症患者总体生存率和生活质量的前景。由于其良好的安全性和临床益处，美国食品药品监督管理局（US FDA）批准了基于聚合物的原位系统以延长局部区域的活性。本文讨论了开发用于靶向递送抗癌药的原位系统的原理，特别强调了用于配制原位系统的聚合物类型。本文还详细讨论了市售的，正在临床试验中的局部抗癌药物递送原位制剂。