Current Drug Delivery - Online First

The spread of tumors (48% in men and 51% in women), as well as the protection of malignant tumors by stromal cells and complex blood vessels, pose significant challenges to drug delivery to tumors. Modern chemotherapy, on the other hand, addresses tumor growth suppression by at least 60% through versatile formulation systems and numerous modifications to drug delivery systems. The renewable and naturally occurring polymers present invariably in all living cells form the fundamental foundation for most anticancer drug development. The review aims to discuss in detail the preparations of polysaccharide, lipid, and protein-based drug-loading vehicles for the targeted delivery of prominent anticancer drugs. It also provides an explanation of drug distribution in blood (cumulative releases of nearly 80% drug) and drug accumulation at tumor sites (1–5 mg/kg) due to enhanced permeability and retention (EPR).

Specific delivery examples for treating colorectal and breast carcinomas have been presented to distinguish the varied drug administration, bioavailability, and tumor internalization mechanisms between sugar, fatty acid, and amino acid polymers. Current therapy possibilities based on cutting-edge literature are provided, along with drug delivery systems tailored to tumor location and invasive properties.

The unique combinations of the three natural polymers provide unparalleled solutions to minimize the toxicity (<20% drug release) of the chemotherapeutic drugs on normal tissues. Moreover, the development of a consolidated drug delivery system has contributed to a substantial reduction (dose reduction from 10.43 µM to 1.9 µM) in the undesirable consequences of higher dosages of chemotherapeutic drugs.

The review extensively covers safe chemotherapeutic systems with significant advantages (tumor volume shrinkage of 4T1 cells from 1000 mm³ to 200 mm³) in clinical applications of carcinoma treatments using natural polymers.

The last strategy in targeted drug delivery systems is to deliver the anticancer drug to the tumor tissue to increase its therapeutic effect and minimize its undesirable side effects. In line with this goal in this research, the redox/pH-responsive disulfide magnetic nanocarriers based on PF127-NH2/L-cysteine-CM-β-CD-FA were synthesized and evaluated in a doxorubicin delivery system.

We effectively surrounded Fe3O4 nanoparticles with SiO2 using the sol-gel method, and then confidently coated them with oleic acid on Fe3O4@SiO2 nanoparticles.. In another reaction, a PF127-NH2/L-cysteine-CM-β-CD-FA was synthesized. The process involved modifying pluronic F127 (PF 127) with maleic anhydride and aminating it to form PF127-NH2. The obtained PF127-NH2 was attached to L-cysteine, followed by condensing with carboxymethyl-β-cyclodextrin and then functionalized by folic acid. Finally, PF127-NH2/L-cysteine-CM-β-CD-FA was coated on the surface of magnetic nanoparticles, and the resulting PF127-NH2/L-cysteine-CM-β-CD-FA was disulfidated to form the final nanocarrier network, which was abbreviated as LCMNPs-SS. The doxorubicin was used as a model drug and loaded into the LCMNPs-SS nanocarrier.

The LCMNPs-SS nanocarrier exhibited excellent properties for controlled release, with a well-defined release rate, a controllable level by an external magnet, and adjusting by DL-dithiothreitol concentration. The LCMNPs-SS nanocarrier could also break apart when exposed to an oxidant or a change in pH. This meant that the drug release could be fine-tuned in response to temperature, pH, or more than one stimulus.

These drug-carrying systems are valuable in reducing the dose of doxorubicin. High internalization of the synthesized LCMNPs-SS caused sped cellular uptake.