'Guapo' (Myrosma cannifolia) starch: a natural product with potential use in cosmetic formulations.

The objective of the present work was to evaluate the possible use of Myrosma cannifolia starch L.F. Maranthaceae ('Guapo'), as a raw material in heterogeneous systems or powdered cosmetic and pharmaceutical products formulation. The starch chemical and physical characteristics, physico-chemical properties, and rheological behaviour, previously studied, were considered. Flowing characteristics, particle size distribution, water absorption capacity at 25 degrees C (ambient temperature), and toxicity were assessed. Results showed that Myrosma starch complies with the USP and British pharmacopoeia, and presented a normal particle distribution. More than 25% of the granules had a diameter >23.81 mum and the average size of particles was >16.92 mum. When compared with talc, 'guapo' starch presented higher values for water absorption capacity and flowing characteristics. Starch showed negative local toxicity, and low acute toxicity in vitro on two human dermis cell types. The amylographic study and the difractograms suggest the possible use of this starch in heterogeneous systems. A facial transparent powder was formulated and some of its properties were determined by sensorial analysis. It was concluded that the M. cannifolia starch presents certain characteristics useful in the formulation of new powdered products.