Rheological Characteristics of Novel Meloxicam-Loaded Complex Organogels Based on Fumed Silica and Poloxamer.

Background: Meloxicam is a non-steroidal anti-inflammatory drug revealing poor solubility in water and good permeability through biological membranes. It is currently administered mostly in forms exerting systemic effects, however, in some conditions topical formulations can be equally useful.

Objective: The objective of the presented work was to formulate and investigate in detail the rheological behavior of non-aqueous gels containing 0.5% of meloxicam in a non-ionic, dissolved form.

Method: Fumed silica and SynperonicTM PE/L 62 were used as structure forming components. Arlasolve ®, Transcutol®, ethanol and DMSO were applied as solubilizers and potential skin absorption enhancers. Three formulations were selected for further investigation and compared to placebo samples. The gels were examined in terms of rheological properties, spreadability and loss of volatile components.

Results: The investigated samples revealed non-Newtonian pseudoplastic behavior with apparent impact of meloxicam on the gel strength. The oscillatory analyses showed an incomplete recovery after structure destruction. Moreover, two yield points were observed, one related to the destruction of fumed silica lattice and the other one to the changes in the spatial arrangement of polymer chains. The tendency to evaporation of volatile components was insignificant. The best spreadability parameter was observed for gels containing Transcutol®.

Conclusion: In this study organogels with meloxicam in dissolved form were obtained and characterized. The performed tests showed that the mechanical properties of the investigated samples depended both on the presence of the drug and on the selection of excipients. The presented data are important in terms of semi-solid product manufacturing and further application by patients.