ABSTRACT
Objective: To prepare the solid lipid nanoparticle (SLN) thermosensitive gel of sinomenine hydrochloride (SH) for intra-articular injection and to investigate its in vitro drug release behavior. Methods: Poloxamer 407 (P-407) and Poloxamer 188 (P-188) were used as gel matrix to prepare the gel, and the gelatinization temperature was applied as a target to optimize the prescription. The SH-SLN was prepared based on the microemulsion technique, and the gel system containing SH-SLN was obtained by cold-dissolving methods. The content of SH was determined by HPLC, in vitro release characteristics of SH-SLN thermosensitive gel were investigated by dialysis method. Results: The optimal gel prescription was finally confirmed as 18% P-407, 5% P-188, and 0.6% HPMC. The gelatination temperature for SH-SLN thermosensitive gel was (34.5 ± 0.2)°C, and the in vitro accumulated release rates of SH in the SLN thermosensitive gel system were (57.79 ± 0.36)% after 24 h and (75.16 ± 0.12)% after 48 h. Conclusion: The SH-SLN thermosensitive gel has the temperature sensitivity and obvious sustained-release effect. The combination of nanoparticle thermosensitive gel will be used as a new drug delivery for intra-articular injection.