In vitro and in vivo evaluation of a xanthan gum- n-octenylsuccinate starch matrix tablet containing ibuprofen as a model drug

Abstract

The bioavailability after oral administration of two sustained release ibuprofen formulations using xanthan gum and a combination of n-octenylsuccinate starch (CL490) and xanthan gum has been investigated in healthy human volunteers and compared with a commercial suspension formulation. The ibuprofen-xanthan gum and the ibuprofen-xanthan gum-CL490 matrix tablets were prepared by direct compression. Three different xanthan gum/CL490 ratios (1:1; 1:4 and 1:10) were investigated in vitro. The xanthan gum/CL490 matrix tablets of a 1 4 and a 1 10 ratio both released nearly 100% after 24 h. No difference was observed in the release profiles between the matrix tablets prepared with 1 1 ratio of xanthan gum and CL490 and with pure xanthan gum during the first 8 h of dissolution test. After 8 h, the release rate from the pure xanthan gum matrix increased (nearly 90% after 24 h) while matrix tablet with a 1 1 ratio of xanthan gum and CL490 released 60% after 24 h. A dry core remained after a 24 h dissolution time period for matrix tablets prepared with the 1 1 ratio of xanthan gum and CL490, while the pure xanthan gum matrix had completely eroded. For the in vivo study, a xanthan gum/CL490 (1:1) matrix tablet was compared to a xanthan gum matrix tablet and a conventional suspension formulation. In comparison with the conventional suspension, the oral bioavailability was 86.83% ± 25.80% ( n = 6) and 75.50% ± 17.18% ( n = 6) for the tablets made with xanthan gum and with a combination of xanthan gum and CL490 (ratio 1 1 ), respectively. The combination of a xanthan gum and CL490 seemed to avoid the initial slow absorption phase in vivo that occurred with a pure xanthan gum matrix tablet. The combination of xanthan gum and n-octenylsuccinate starch could offer some advantages in the formulation of sustained release hydrophilic matrix tablets.