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.