Study of an injectable in situ forming gel for sustained-release of Ivermectin in vitro and in vivo

The purpose of this study was to develop an in situ forming gel based on SAIB-PLA composite matrix depot for sustained release of Ivermectin. The burst release and cumulative release were significantly reduced with the increased content of solvents and the minimum burst release and cumulative release were found in formulations with NMP. With the addition of PLA in the NMP based gel, burst release and cumulative release were reduced. When concentration of IVM raised from 1% to 2% and 4%, cumulative release was 2.4–2.9 and 3.1–3.7 times that of 1%. The optimal prescription displayed a slow in vitro release rate with 10.46% burst release and 80% cumulative release in 80 days. Pharmacokinetic results indicate that the effective blood concentration of the gel could be maintained up to 110–120 days, t1/2λz of the gels was (24.37 ± 1.71) days and MRT was (32.86 ± 0.91) days.