"Preformulation studies to guide the production of a mucoadhesive oral film containing triamcinolone acetonide by hot-melt extrusion for the treatment of recurrent aphthous stomatitis".
Recurrent aphthous stomatitis; Triamcinolone acetonide; Hot-melt extrusion; Preformulation; Amorphous solid dispersion; Oral film.
Recurrent aphthous stomatitis (RAS) is the most widespread oral disease, affecting up to 25% of the global population. Triamcinolone acetonide (TA) has been widely used in the topical treatment of RAS, but current pharmaceutical forms are not efficient for this purpose, so there is a significant need to develop an improved drug administration system. This work proposes to obtain a TA-containing amorphous solid dispersion (ASD) processed by hotmelt extrusion (HME) in the form of a mucoadhesive oral film as an alternative to the RAS treatment. To this end, a detailed preformulation protocol was carried out using theoretical and experimental approaches, leading to the selection of four polymers and a plasticizer. From the Hansen solubility parameters (HSPs) the miscibility of the drug with the polymers was predicted as PVA > EUD > PVPVA > HPMCAS, while thermal analysis (DSC) showed an experimental miscibility, based on the percentage of drug in amorphous state as follows: EUD (81.07%) > PVA (67.55%) > PVPVA (45.57%) > HPMCAS (8.46%). The DTG curves showed instability problems with PVA, PVPVA and HMPCAS, as well as the plasticizer (TEC) evaporation. FTIR spectra confirm the instability and exhibit the maintenance of TEC within the HME processing temperature. The TA-EUD-TEC mixture (10:60:30, w/w) was successfully extruded forming an ASD in the form of a mucoadhesive oral film with a thickness of 0.69 ± 0.06 mm, moderate adhesive potential (0.216N ± 0.031), and 99.6% of drug content. The physicochemical characterization was carried out by DSC, TGA, FTIR and SEM. The results suggest partial evaporation of the liquid plasticizer and formation of heat-dependent anhydrides derived from the polymer chain, thus, the stability of the drug within the polymer matrix must be carefully evaluated. Notably, the pre-plasticization procedure was a key parameter for the success of the HME process.