Abstract 5817: pH responsive delivery of gemcitabine/pirarubicin co-loaded biodegradable polymeric nanoparticles for synergistic anti-cancer therapy

Abstract Gemcitabine, a nucleoside antimetabolite, is a widely known chemotherapeutic agent being used as a first line treatment alone or in combination with other chemo drugs for different types of cancer. However, due to its extremely short half-life in the body caused by enzymatic degradation and poor pharmacokinetics, the I. V. dosage of administration is quite high i. e. , 1000 mg/m2 for metastatic breast cancer treatment. Moreover, gemcitabine in combination with anthracyclines imparts synergy but free anthracyclines are reported to be associated with long term cardiac toxicity. Nanoparticle-based drug delivery systems have provided a befitted solution for improving the poor pharmacokinetic properties and systemic toxicity caused by the chemo drugs because of their ability to improve bioavailability of the drugs at the desired site as well as overcoming multi-drug resistance (MDR). In the present work, PLA-based biodegradable block copolymeric nanoparticles have been employed to co-load Gemcitabine and Pirarubicin for improved anti-cancer activity. Gemcitabine and Pirarubicin have been chemically conjugated to the amphiphilic block copolymer mPEG PLA via a pH responsive Schiff’s Base linkage using a linker molecule Levulinic acid. The prepared PIRA/GEM co-loaded nanoparticles exhibited an optimum size, zeta potential and polydispersity index i. e. , 187 ± 3. 5 nm, -10 ± 2. 0 and 0. 1 PDI respectively. Further, in the drug release experiments, these Nps displayed sustained and higher drug release in lysosomal pH (pH 5. 0) than in the physiological buffer environment (pH 7. 4) attributed to the pH sensitive bonding. The co-loaded Nps were prepared in multiple ratios (Pira: Gem - 1: 1, 1: 3, and 3: 1) and investigated for in-vitro cellular inhibition studies in comparison to singly loaded drug Nps and corresponding free drug formulations in various breast cancer cell lines. Additionally, apoptotic studies revealed significant enhancement in synergistic activity in the case of PIRA/GEM co-loaded Nps in comparison to conventional free drug formulations. In conclusion, this nano-formulation demonstrated excellent anti-cancer activity against breast cancer cells therefore it may be used as a potential candidate for therapeutic use. Citation Format: Priya Gupta, Surender M. Kharbanda, Harpal Singh. pH responsive delivery of gemcitabine/pirarubicin co-loaded biodegradable polymeric nanoparticles for synergistic anti-cancer therapy abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 5817.