Purpose: To characterize some preformulation properties of aqueous stem bark extract of Bridelia ferruginea Benth (Euphorbiaceae) (BF).              

Methods: The stem bark was extracted by maceration in hot distilled water. Two batches of granules containing the extract were prepared by wet granulation using maize starch, polyvinylpyrrolidone (PVP), Avicel^® PH-101, magnesium stearate, acacia and lactose as excipients. Some physicochemical and micromeritic properties of the powdered extract and granules were determined following standard procedures.                                     

Results: The pH of the aqueous BF extract was 5.4 ± 0.1 while the moisture content of the dry extract was 12.0 %. Total ash value of the extract was 7.91 ± 0.03. Particle size increased after granulation from 228 to 531 µm in the order: granules 1 > granules 2 > powder. The bulk and tapped densities decreased significantly (p < 0.05) from 0.40 ± 0.04 to 0.77 ± 0.09 and 0.49 ± 0.05 to 0.85 ± 0.09 g/ml, respectively in the order: granules 2 < granules 1 < powder. Similarly, the angle of repose increased after granulation from 24.0 ± 0.5 to 25.4 ± 0.9 ^o in the order: granules 2 < granules 1 < powder (p < 0.05). The flow rate and compressibility of the granules (2.45 ± 0.08 g/min and 0.17, respectively) improved significantly (p < 0.05) over those of the powdered BF extract (2.34 ± 0.05 g/min and 0.26, respectively).

Conclusion: The results of this preformulation study indicates that the powdered extract of Bridelia ferruginea possesses properties that make it suitable for its formulation into standard solid dosage forms.