Spray-dried thermally modified rice starch was tested for its feasibility as a film-forming material with a sustained-release profile. Various coating formulations were prepared using PEG8000, HPC-LF and glycerol as plasticizers. Opadry-1, Opadry-2 and HPMC (with PEG8000 as a plasticizer) were used as reference coating formulations. The film-forming properties of these formulations were tested via application on OHP film and checking various parameters, including elongation, tensile strength and thickness. Tablets were coated with the above-mentioned formulations and checked for the appearance of film and morphology using CLSM imaging. Various mechanical properties of the tablets, including hardness, friability and size dimensions, were also analyzed. The results from these tests were analyzed, and the formulation containing glycerol was found to be best coating formulation amongst them. SDTMR containing glycerol was also coated on tablets with different coating weight gains of 3 %, 6 %, 9 %, 12 % and 15 %. SEM imaging and dissolution tests were performed to check morphologies and sustained release behaviors of the coated tablets. Tablets with higher coating weight gains showed gradual decreases in drug release in the beginning. In pH 1.2 media, the tablets showed significant sustained release of drug compared to uncoated tablets. However, in water and pH 6.8 media, the drug release rates increased rapidly later in testing, and the time for total drug release was similar to that of uncoated tablets. We conclude that SDTMR with glycerol as a plasticizer can be utilized as a film-forming agent. Further tests on dissolution involving transfer of undissolved tablets from pH 1.2 media to pH 6.8 is required to better understand the sustained-release properties of this film.
