Formula Optimization of 5-Aminosalicylic Acid Enema In Situ Gel by Factorial Design/Response Surface Methodology / 中国药师

ABSTRACT

Objective:To optimize the formula of 5-aminosalicylic acid enema in situ gel. Methods:5-Aminosalicylic acid ene-mas in situ gel was prepared using a cold dissolution method with carbomer as the gel matrix and xanthan gum as the thickener. A 32 full factorial design was used to investigate the effects of the concentrations of carbomer and xanthan gum on the viscosity before and af-ter the gelling, duration of inversion tube and sedimentation rate. Response surface methodology was used to optimize the formula. Re-sultsThe quantitative relationships between the two factors and the four evaluation indices were obtained. The optimum formula was as followsthe concentration of carbopol and xanthan gum in the enema was 0. 7% and 0. 15%, respectively. The viscosity before and af-ter the gelling was 500-1 000 mPa·s and 2 200-2 700 mPa·s, respectively. The duration of inversion tube test was 40-80 min and the sedimentation rate was more than 98. 5%. Conclusion:The multi-objective simultaneous optimization of the formula of 5-aminosal-icylic acid enema in situ gel is accomplished by factorial design and response surface methodology.