Solvent cast films are used as oral strips with potential to adhere to the mucosal surface, hydrate and deliver drugsudacross the buccal membrane. The objective of this study was the formulation development of bioadhesive films withudoptimum drug loading for buccal delivery. Films prepared from κ-carrageenan, poloxamer and polyethylene glycol orudglycerol, were loaded with ibuprofen as a model water insoluble drug. The films were characterized using textureudanalysis (TA), hot stage microscopy (HSM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA),udscanning electron microscopy (SEM), x-ray powder diffraction (XRPD), high performance liquid chromatographyud(HPLC) and in vitro drug dissolution. Optimized films were obtained from aqueous gels containing 2.5% w/w κ-carrageenanud911, 4% w/w poloxamer 407 and polyethylene glycol (PEG) 600 [5.5% w/w (non-drug loaded) and 6.5% w/wud(drug loaded)]. A maximum of 0.8% w/w ibuprofen could be incorporated into the gels to obtain films with optimumudcharacteristics. Texture analysis confirmed that optimum film flexibility was achieved from 5.5% w/w and 6.5% (w/w)udof PEG 600 for blank films and ibuprofen loaded films respectively. TGA showed residual water content of the films asudapproximately 5%. DSC revealed a Tg for ibuprofen at −53.87°C, a unified Tm for PEG 600/poloxamer mixture atud32.74°C and the existence of ibuprofen in amorphous form, and confirmed by XRPD. Drug dissolution at a pH simulatingudthat of saliva showed that amorphous ibuprofen was released from the films at a faster rate than the pure crystallineuddrug. The results show successful design of a carrageenan and poloxamer based drug delivery system with potential forudbuccal drug delivery and showed the conversion of crystalline ibuprofen to the amorphous form during film formation.
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