**Recent Advances in Polymer Nanomaterials for Drug Delivery of Adjuvants in Colorectal Cancer Treatment: A Scientific-Technological Analysis and Review**

### **Marlon Osorio 1, Estefanía Martinez 1, Tonny Naranjo 2,3 and Cristina Castro 1,\***


Academic Editors: Carlos A. García-González, Pasquale Del Gaudio and Ricardo Starbird Received: 19 April 2020; Accepted: 1 May 2020; Published: 12 May 2020

**Abstract:** Colorectal cancer (CRC) is the type with the second highest morbidity. Recently, a grea<sup>t</sup> number of bioactive compounds and encapsulation techniques have been developed. Thus, this paper aims to review the drug delivery strategies for chemotherapy adjuvant treatments for CRC, including an initial scientific-technological analysis of the papers and patents related to cancer, CRC, and adjuvant treatments. For 2018, a total of 167,366 cancer-related papers and 306,240 patents were found. Adjuvant treatments represented 39.3% of the total CRC patents, indicating the importance of adjuvants in the prognosis of patients. Chemotherapy adjuvants can be divided into two groups, natural and synthetic (5-fluorouracil and derivatives). Both groups can be encapsulated using polymers. Polymer-based drug delivery systems can be classified according to polymer nature. From those, anionic polymers have garnered the most attention, because they are pH responsive. The use of polymers tailors the desorption profile, improving drug bioavailability and enhancing the local treatment of CRC via oral administration. Finally, it can be concluded that antioxidants are emerging compounds that can complement today's chemotherapy treatments. In the long term, encapsulated antioxidants will replace synthetic drugs and will play an important role in curing CRC.

**Keywords:** colorectal cancer; antioxidants; 5-fluorouracil; polymer nanomaterials; nanocapsules; chemotherapy
