Poloxamer micellar system for intra-articular injection of 15-deoxy-Δ12,14-prostaglandin J2 with improved bioavailability and anti-inflammatory properties in the temporomandibular joint of rats

Painful conditions of the temporomandibular joint (TMJ) are challenging to manage and most attempts often result in unsatisfactory outcomes. In such context, nanocarrier systems, such as polymeric micelles, have been showing encouraging results in solving therapeutic limitations. Poloxamers are widely used, especially PL 407, because of their high biocompatibility and approval by the Food and Drug Administration (FDA) for clinical use. 15-deoxy-(Delta 12,14)-prostaglandin J(2) (15d-PGJ(2)) has shown important antinociceptive and anti-inflammatory activity. The present study evaluated the efficacy and viability of the micellar system of PL-15dPGJ(2) in a formalin-induced acute pain model in the temporomandibular joint of rats. The PL-15dPGJ(2) was prepared and characterized. The animals were pretreated with an intra-articular injection of PL-15dPGJ(2) followed by the formalin challenge. The nociceptive response was evaluated at different time-periods and the periarticular tissue and articular wash were collected for analysis. We found that intra-articular injection of PL-15d-PGJ(2) produced pain relief at lower concentrations and in a sustained manner compared with free 15d-PGJ(2). Moreover, a strong anti-inflammatory effect was observed with decreased levels of key pro-inflammatory cytokines and modulation of the leukocyte migration process. Our findings suggest that 15d-PGJ(2) combined with a poloxamer micellar system provided clinical relevance in terms of bioavailability, long-lasting effect, and safe dosage. The formulation investigated herein is a promising micellar carrier system for managing pain conditions of the TMJ.