Construction of gambogic acid HPMA Copolymer Coupling drug system and study on anti-tumor activity

Purpose: An active-passive dual-targeting gambogic acid HPMA Copolymer Coupling drug system with high efficiency, low toxicity and high selectivity was constructed. Methods: The gambogic acid HPMA copolymer coupling drug system was constructed and its structure was characterized. The cytotoxicity of gambogic acid HPMA copolymer was detected by MTT assay. The pharmacokinetics of gambogic acid HPMA copolymer was evaluated in mice. Targetability of gambogic acid HPMA copolymer was evaluated by tissue distribution experiment. The in vitro antitumor activity of gambogic acid HPMA copolymer was evaluated by pharmacodynamics experiment in mice. Results : Two copolymers of gambogic acid HPMA were successfully prepared. The copolymers showed reduced cytotoxicity and a certain sustained release effect and targeting property. In vivo pharmacodynamic experiments also showed better anti-tumor effects than GA. Discussion: In this study, gambogic acid was combined with HPMA polymer and the targeting molecule D-galactose/folic acid to form a polymer micelle with high efficiency, low toxicity and high selectivity for active-passive dual targeting. The construction of the drug system provides new ideas for future formulation research and development.

HPMA Copolymer-Based Nanomedicines in Controlled Drug Delivery

Recently, numerous polymer materials have been employed as drug carrier systems in medicinal research, and their detailed properties have been thoroughly evaluated. Water-soluble polymer carriers play a significant role between these studied polymer systems as they are advantageously applied as carriers of low-molecular-weight drugs and compounds, e.g., cytostatic agents, anti-inflammatory drugs, antimicrobial molecules, or multidrug resistance inhibitors. Covalent attachment of carried molecules using a biodegradable spacer is strongly preferred, as such design ensures the controlled release of the drug in the place of a desired pharmacological effect in a reasonable time-dependent manner. Importantly, the synthetic polymer biomaterials based on N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers are recognized drug carriers with unique properties that nominate them among the most serious nanomedicines candidates for human clinical trials. This review focuses on advances in the development of HPMA copolymer-based nanomedicines within the passive and active targeting into the place of desired pharmacological effect, tumors, inflammation or bacterial infection sites. Specifically, this review highlights the safety issues of HPMA polymer-based drug carriers concerning the structure of nanomedicines. The main impact consists of the improvement of targeting ability, especially concerning the enhanced and permeability retention (EPR) effect.

Structure-to-Efficacy Relationship of HPMA-Based Nanomedicines: The Tumor Spheroid Penetration Study

Nanomedicines are a novel class of therapeutics that benefit from the nano dimensions of the drug carrier. These nanosystems are highly advantageous mainly within cancer treatment due to their enhanced tumor accumulation. Monolayer tumor cells frequently used in routine preclinical assessment of nanotherapeutics do not have a spatial structural architecture that allows the investigation of the penetration of nanomedicines to predict their behavior in real tumor tissue. Therefore, tumor spheroids from colon carcinoma C26 cells and glioblastoma U87-MG cells were used as 3D in vitro models to analyze the effect of the inner structure, hydrodynamic size, dispersity, and biodegradability of N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-based nanomedicines carrying anticancer drug pirarubicin (THP) on the penetration within spheroids. While almost identical penetration through spheroids of linear and star-like copolymers and also their conjugates with THP was observed, THP penetration after nanomedicines application was considerably deeper than for the free THP, thus proving the benefit of polymer carriers. The cytotoxicity of THP-polymer nanomedicines against tumor cell spheroids was almost identical as for the free THP, whereas the 2D cell cytotoxicity of these nanomedicines is usually lower. The nanomedicines thus proved the enhanced efficacy within the more realistic 3D tumor cell spheroid system.