Tropical Journal of Pharmaceutical Research
Official Journal of Pharmacotherpy Group
Home Pharmacotherapy Group African Journals Online

Compounded laxative formulations for substituting phenolphthalein with sennosides A & B in solid dosage forms

Quintin Verloop1, Wilna Liebenberg1, Andries F. Marais1, Antonie P. Lötter1 and Melgardt M. de Villiers2

1School of Pharmacy, North-West University, Potchefstroom Campus, Potchefstroom 2520, South Africa and 2School of Pharmacy, University of Louisiana at Monroe, Monroe, LA 71209, USA.


Tropical Journal of Pharmaceutical Research 2004; 3(1): 265-277

Abstract  Full-Text

Purpose: Following the discovery of the carcinogenicity of phenolphthalein and the subsequent ban of this compound in several countries this study was undertaken to develop compounded formulations of laxative products containing the stimulant laxatives sennosides A and B.

Methods: DSC and HPLC analysis was used to determine the compatibility of sennosides with commonly used excipients before compounding capsules, tablets and effervescent tablets containing sennosides A & B. The physical and chemical stability and release properties of these dosage forms were determined for 12 weeks at increased temperature and relative humidity.

Results: Sennosides A & B were compatible with a wide variety of powdered excipients. However, these were incompatible with propyl paraben, sodium carbonate, stearic acid, citric acid, PEG, and sugar derivatives such as lactose, glucose and sorbitol when granulated with water. Not withstanding these interactions, it was possible to compound simple capsule, tablet and even an effervescent tablet formulations containing sennosides A & B that complied with pharmacopeial specifications. However, all these formulations were sensitive to moisture because when stored at increased temperature and relative humidity, disintegration times increased and dissolution rates decreased.

Conclusion: Based on compatibility and stability studies simple, stable and elegant solid dosage forms containing sennosides A & B were compounded that can be used to replace phenolphthalein in a variety of solid dosage forms.


Key words:  Compounding; Sennosides A & B; Phenolphthalein replacement; Drug-Excipient Compatibility.

To whom correspondence should be addressed: Fax: +1 318 342-3255; E-mail:

Copyright @2002-2006. TJPR Faculty of Pharmacy, University of Benin, Benin City, Nigeria
Tel: +234 802 3360318 Fax: +234 52 602257 E-mail:
Last updated: January 11, 2006