Model suspensions of indomethacin "solvent deposited" on cellulose polymers

The properties of indomethacin "sorbates" with hydrophilic cellulose carriers (optimal drug/carrier ratio 1:1 (w/w)) were studied in the solid state and in the form of 0.5% aqueous dispersions. The polymers used were: methyl-(MC), hydroxyethyl-(HEC), hydroxyethylmethyl-(HEMC), hydroxypropyl-(HPC), sodium carboxymethyl-(CMC-Na) and microcrystalline celluloses. It was found that the "solvent deposited" indomethacin, unlike the pure drug, exists predominantly as the alpha-polymorph, and possesses improved wettability and higher aqueous solubility (the increase was approximately 2-3 times). The indomethacin/cellulose sorbates can be easily transformed into 0.5% aqueous dispersions. The "primary" dispersions were used as a basis for the formulation of new oral suspensions with improved rheological properties and physical stability. The new models behave as non-Newtonian fluids with pseudoplastic flow and good sediment redispersibility after shaking. The indomethacin/carboxymethylcellulose sodium 1:1 (w/w) sorbate suspension is the most suitable for future practical application.