Thermosensitive poloxamer-based injectables as controlled drug release platforms for veterinary use: development and in-vitro evaluation

Abstract

The aim of this work was to explore the potential of combining two different poloxamers (P407 and P188) with κ-carrageenan and sodium chloride for their utilization in the design of thermosensitive injectable depot systems for drug release. These delivery platforms were designed by combination of two different poloxamers (P407 and P188) with κ-carrageenan and sodium chloride. The addition of 10-15% w/w P188 in the poloxamer solution containing 28% w/w P407 allowed optimal gelation temperatures (24-28 °C) and a quick gelation process (30 s). The addition of 0.1% w/w of κ- carrageenan increased 3-fold the gel strength and did not change gelation temperature, compared with P407/P188 (28/15% w/w) alone. On the other hand, sodium chloride increased the gel strength and decreased the gelation temperature as a function of its concentration. In in-vitro release experiments, κ-carrageenan decreased the release rate of progesterone and reduced significantly the gel erosion in 48 h. This study demonstrates that addition of κ-carrageenan and sodium chloride into poloxamers blends can be considered a useful tool to design thermosensitive platforms, if added in suitable amounts. In conclusion, this system offers a promising alternative to development of injectable depot controlled drug release platforms for veterinary use.