Development of pulsatile release compression coated tablets using combination of time dependent and pH sensitive approaches was suitable to target the flurbiprofen to colon.

Thus, the compression-coated tablets based on time-dependent approach were preferred for colon-targeted delivery of ketorolac.

Present research deals with the development of compression-coated flurbiprofen colon-targeted tablets to retard the drug release in the upper gastro intestinal system, but progressively release the drug in the colon. Flurbiprofen core tablets were prepared by direct compression method and were compression coated using sodium alginate and Eudragit S100. The formulation is optimized based on the in vitro drug release study and further evaluated by X-ray imaging and pharmacokinetic studies in healthy humans for colonic delivery. The optimized formulation showed negligible drug release (4.33 ± 0.06 %) in the initial lag period followed by progressive release (100.78 ± 0.64 %) for 24 h. The X-ray imaging in human volunteers showed that the tablets reached the colon without disintegrating in the upper gastrointestinal tract. The C max of colon-targeted tablets was 12,374.67 ng/ml at T max 10 h, where as in case of immediate release tablets the C max was 15,677.52 ng/ml at T max 3 h, that signifies the ability of compression-coated tablets to target the colon. Development of compression-coated tablets using combination of time-dependent and pH-sensitive approaches was suitable to target the flurbiprofen to colon.

The rationale of the present study is to formulate flurbiprofen colon targeted compression coated tablets using guar gum to improve the therapeutic efficacy by increasing drug levels in colon, and also to reduce the side effects in upper gastrointestinal tract. Direct compression method was used to prepare flurbiprofen core tablets, and they were compression coated with guar gum. Then the tablets were optimized with the support of in vitro dissolution studies, and further it was proved by pharmacokinetic studies. The optimized formulation (F4) showed almost complete drug release in the colon (99.86%) within 24 h without drug loss in the initial lag period of 5 h (only 6.84% drug release was observed during this period). The pharmacokinetic estimations proved the capability of guar gum compression coated tablets to achieve colon targeting. The C max of colon targeted tablets was 11956.15 ng/mL at T max of 10 h whereas it was 15677.52 ng/mL at 3 h in case of immediate release tablets. The area under the curve for the immediate release and compression coated tablets was 40385.78 and 78214.50 ng-h/mL and the mean resident time was 3.49 and 10.78 h, respectively. In conclusion, formulation of guar gum compression coated tablets was appropriate for colon targeting of flurbiprofen.

The present study was intended to formulate the ketoprofen emulgels using different viscosity grades of hydroxypropyl methylcellulose and carbopol as gelling agents. All the prepared emulgels were shown acceptable physical properties concerning colour, homogeneity, consistency, and pH value. Emulgels containing hydroxypropyl methylcellulose were poor in clarity when compared to carbopol formulations. The influence of the type of gelling agent on the drug release from the prepared emulgels was investigated and carbopol 934 showed good results not only in the drug release but also in physical evaluation parameters. From the drug release studies, F3 formulation showed 98.46±2.05% drug release in 8 h with good clarity and physical appearance. The T10% and T80% values of best formulation F3 was found to be 0.9 h and 6.6 h respectively. The T10% and T80% was higher for formulations with carbopol in low concentration when compared to hydroxypropyl methylcellulose K 4M and K 15M in high concentrations, indicating better controlled release. FTIR studies proved the compatibility between drug and carbopol. From the stability studies, similarity index value between dissolution profiles of F3 formulation before and after storage was found to be 87.16. Hence the development of ketoprofen emulgels is a suitable way for topical administration.