Negative intercepts in the Heckel analysis of the crude extract of Vernonia galamensis: A major setback of the equation

Abstract

Introduction: The dry powdered leaf of Vernonia galamensis (Asteraceae) has been
used by traditional herbalists in northern Nigeria to treat diabetes mellitus. However,
medicinal plants used in folk medicine have no standard dose or acceptable method of
formulation. In this study therefore, the leaves of Vernonia galamensis (Asteraceae) were
extracted, evaluated for pharmacological activity and formulated into tablets. Materials
and Methods: The extract was found to be highly hygroscopic and deliquescent,
therefore the following efflorescent diluents; aerosil® 200 (GmbH, Meggle, Germany),
avicel PH 101 (Honey Well and Stein, UK), and anhydrous calcium phosphate (BDH
chemicals, England) were used. The wet granulation method was employed for the tablet
formulation and the compaction characteristics of the granules were determined using
the Heckel equation. Results and Conclusions: Negative intercepts were a setback to
the use of the Heckel equation due to the resulting negative values of DA and DB. This
makes it difficult to explain the compaction characteristics of the crude extract.