This work explores the first use of UV imaging in liquisolid systems. The aim of this study was to simultaneously measure a model drug propranolol hydrochloride (PPN) release and compact swelling behaviour from liquisolid systems using sesamum radiatum gum by exploiting the visible and UV imaging capabilities of the novel surface dissolution instrument (SDI2).Liquisolid compacts were successfully prepared using polysorbate 80 as the liquid solvent.The influence of either colloidal silica or veegum (magnesium aluminium silicate) was also evaluated in the liquisolid sesamum gum compacts. Solid-state characterization using differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD) showed a decrease in the crystallinity of the model cationic drug. Visible and UV imaging was successfully used to detect differences between the conventional or physical mixture formulations containing veegum or colloidal silica and the liquisolid preparations as well as differences between their swelling behaviour. The use of this imaging technique provides added insights into the drug release behaviour of formulations.

This study was aimed at investigating the effect of grewia polysaccharides on the mechanical and release properties of tablet matrices containing binary mixtures of the polysaccharide with psyllium. Two grades of grewia polysaccharides (GG and GDS) were extracted and binary mixtures of the polysaccharides with psyllium were formulated into tablet matrices containing theophylline as the model drug. The true, bulk and tapped densities, Carr's compressibility index of the powders and binary composites were determined before tablet compression. Tablet properties (hardness, porosity, and drug release from the matrices) were investigated. The dissolution test was carried out in 0.1M HCl (pH 1.2) and phosphate buffer (pH 6.8). The results show that GG and GDS produced tablets with good mechanical strength (108.33 N and 95.70 N, respectively) while psyllium produced softer tablets (7.13 N). The combination of psyllium and grewia polysaccharides in the matrices resulted in a significant increase in the mechanical strength of the matrices when compared to matrices containing psyllium alone as the matrix former. The results also showed that GG and GDS reduced the dissolution rate and effectively eliminated the burst release of theophylline from the psyllium matrices at both pHs. The matrices of GG or GDS and the binary mixtures conform to non-Fickian anomalous diffusion with n > 0.45. When overcoming the burst release of drug from matrices such as psyllium, grewia polysaccharides may provide an effective reduction and a more sustained drug release from such matrices.

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