Pharmacokinetic and efficacy study of cisplatin and paclitaxel formulated in a new injectable poly(sebacic-co-ricinoleic acid) polymer.

Injectable biodegradable polymer poly(sebacic-co-ricinoleic acid), P(SA-RA) is currently under development for intratumoral (IT) delivery of drugs for treating solid tumors. This study presents formulation development, pharmacokinetic and efficacy studies of two anticancer drugs (cisplatin and paclitaxel) formulated with P(SA-RA) polymer. In pharmacokinetic study, systemic exposure and pharmacokinetic parameters of cisplatin/paclitaxel following single intravenous (IV) or subcutaneous (SC) doses of cisplatin/paclitaxel was compared with intramuscular (IM) or SC doses of cisplatin/paclitaxel formulated with P(SA-RA) polymer in male CD rat. Simultaneously, the tumor reduction effect and toxicity for these formulations were evaluated in human FaDu head and neck tumor xenograft subcutaneous nude mouse model. Pharmacokinetic data reflect the lower maximal concentrations and sustained release of polymer-cisplatin/paclitaxel formulations compared to standard cisplatin/paclitaxel administration. Regarding efficacy study, a single IT or near the tumor injection (NT) of polymer-paclitaxel or polymer-cisplatin formulation significantly reduced the tumor size, compared to the standard paclitaxel or cisplatin treatments. No death or toxicity and no effect on body weight as well as macroscopic and/or microscopic changes in or near the injected area were observed, proving biocompatibility and acceptability of polymer-formulations. In conclusion, the developed formulation demonstrated controlled release and significant efficacy in delivering these agents and exhibit potential for further clinical development.

In vivo administration of BL-3050: highly stable engineered PON1-HDL complexes.

BACKGROUND: Serum paraoxonase (PON1) is a high density lipoprotein (HDL)-associated enzyme involved in organophosphate (OP) degradation and prevention of atherosclerosis. PON1 comprises a potential candidate for in vivo therapeutics, as an anti-atherogenic agent, and for detoxification of pesticides and nerve agents. Because human PON1 exhibits limited stability, engineered, recombinant PON1 (rePON1) variants that were designed for higher reactivity, solubility, stability, and bacterial expression, are candidates for treatment. This work addresses the feasibility of in vivo administration of rePON1, and its HDL complex, as a potentially therapeutic agent dubbed BL-3050. METHODS: For stability studies we applied different challenges related to the in vivo disfunctionalization of HDL and PON1 and tested for inactivation of PON1's activity. We applied acute, repetitive administrations of BL-3050 in mice to assess its toxicity and adverse immune responses. The in vivo efficacy of recombinant PON1 and BL-3050 were tested with an animal model of chlorpyrifos-oxon poisoning. RESULTS: Inactivation studies show significantly improved in vitro lifespan of the engineered rePON1 relative to human PON1. Significant sequence changes relative to human PON1 might hamper the in vivo applicability of BL-3050 due to adverse immune responses. However, we observed no toxic effects in mice subjected to repetitive administration of BL-3050, suggesting that BL-3050 could be safely used. To further evaluate the activity of BL-3050 in vivo, we applied an animal model that mimics human organophosphate poisoning. In these studies, a significant advantages of rePON1 and BL-3050 (>87.5% survival versus <37.5% in the control groups) was observed. Furthermore, BL-3050 and rePON1 were superior to the conventional treatment of atropine-2-PAM as a prophylactic treatment for OP poisoning. CONCLUSION: In vitro and in vivo data described here demonstrate the potential advantages of rePON1 and BL-3050 for treatment of OP toxicity and chronic cardiovascular diseases like atherosclerosis. The in vivo data also suggest that rePON1 and BL-3050 are stable and safe, and could be used for acute, and possibly repeated treatments, with no adverse effects.