ABSTRACT
The objectives of the study were to formulate hydroxypropyl methyl cellulose-based controlled release matrix tablets for theophylline with varying drug:polymer ratios (1:1 and 1:2) and differing tablet hardness (5, 6 and 7 kg/cm(2)), and to evaluate the tablet's physico-chemical properties such as hardness, uniformity of weight, friability, drug content and in vitro drug release. Initially, granules were made by wet granulation technique and evaluated for angle of repose, bulk density, tapped density, bulkiness, compressibility index and hausner ratio. The results indicate good flow property of the granules and thus, the evaluated tablet physical properties were within the acceptable limits. The FT-IR study for the F-6 formulation showed that there was no interaction between the drug and the polymer. In vitro release studies were performed using Disso-2000 (paddle method) in 900 ml of pH 7.4 at 50 rpm. The result indicated that at high drug:polymer ratio (1:2) and hardness value 7 kg/cm(2), prolonged drug release was observed than the low drug: polymer ratio (1:1) and hardness values (5 and 6 kg/cm(2)). The release kinetics was found to follow korsmeyers-peppas model and the mechanism of drug release was by non-fickian or anomalous diffusion. The F-6 formulation was chosen for stability studies. F-6 formulation was stable when it was kept at different temperatures for a period of 6 months.
ABSTRACT
The objectives of the present work were to prepare castor oil-based nano-sized emulsion containing cationic droplets stabilized by poloxamer-chitosan emulgator film and to assess the kinetic stability of the prepared cationic emulsion after subjecting it to thermal processing and freeze-thaw cycling. Presence of cryoprotectants (5%, w/w, sucrose +5%, w/w, sorbitol) improved the stability of emulsions to droplet aggregation during freeze-thaw cycling. After storing the emulsion at 4 degrees C, 25 degrees C, and 37 degrees C over a period of up to 6 months, no significant change was noted in mean diameter of the dispersed oil droplets. However, the emulsion stored at the highest temperature did show a progressive decrease in the pH and zeta potential values, whereas the emulsion kept at the lowest temperatures did not. This indicates that at 37 degrees C, free fatty acids were formed from the castor oil, and consequently, the liberated free fatty acids were responsible for the reduction in the emulsion pH and zeta potential values. Thus, the injectable castor oil-based nano-sized emulsion could be useful for incorporating various active pharmaceutical ingredients that are in size from small molecular drugs to large macromolecules such as oligonucleotides.
