Efficacy of poly(sebacic acid-co-ricinoleic acid) biodegradable delivery system for intratumoral delivery of paclitaxel

The effectiveness of an injectable polymeric formulation, based on poly(sebacic acid-co-ricinoleic acid) and paclitaxel against a heterotopic tumor model was studied. An injectable pasty polymer that releases an incorporated drug over a period of weeks was used. The degradation rate of formulations with paclitaxel was examined in vitro and in vivo. The effectiveness of the polymeric carrier of paclitaxel was investigated using a melanoma heterotopic model in C57BL/6 mice. Tumor bearing animals were injected intratumorally with 0.1 ml of formulations containing 5%, 10%, 15%, and 20% paclitaxel. Formulations with 5% and 10% paclitaxel content degraded faster in vivo then in vitro. Changes in tumor progression, survival time, and body weight were observed over a period of 77 days. The highest tumor size was reported for the control groups that did not receive paclitaxel in their treatment regiment: 3.6 g on day 20, while in all groups treated with polymer loaded with paclitaxel the tumor size was much smaller than that in the blank polymer or non treatment groups and ranged from 1.3 g to 0.3 g. Intratumoral injection of paclitaxel loaded in the polymer was found to be an effective treatment for localized tumors.