Modulatory effect of high molecular weight polyethylene glycols on drug release from ibuprofen matrix tablets

The work aim at investigating the channeling or modulatory effects of polyethylene glycol (PEG) (MW 4000 and 6000) on drug release from ibuprofen sustained release formulation. Different batches of ibuprofen matrix granules and tablet were prepared by melt granulation using different concentrations of carnauba wax and PEG at different ratios. The granule flow properties and various tablets parameters were evaluated using standard procedures. Drug release kinetics and mechanisms from the tablets were investigated as well as DSC and FTIR drug-excipients compatibility. The granules showed increasingly close packing with increase in the amounts of PEG incorporated. All the tablets did not meet compendial specifications with regard to crushing strength and friability. The release rate and extent of release were found to be influenced by the amount of PEG used as well as the carnauba wax concentration. PEG combination of equal amounts produced the highest release of 91 % in the formulation prepared with 12.20 %w/w of carnauba wax while a 1:2 combination in tablets prepared with 24.40 %w/w of carnauba wax gave a maximum drug release of 83 %. Drug release kinetic and mechanism were most consistent with the Higuchi model hence the release was diffusion mediated. DSC and FTIR studies showed no interactions between ibuprofen and the excipients. Carnauba wax-PEG system can be used successfully as a matrix former to sustain the release of ibuprofen for over 6 h. The studies indicate that the proper balance between a matrix former and a channeling agent can produce a desired drug dissolution profile.