Physicochemical Properties of Phytopharmaceutical Preparations as Affected by Drying Methods and Carriers

Abstract

This article reports a study of the effects of the drying methods and drying carriers on system performance and physicochemical properties of spray- and spouted bed–dried phytopharmaceutical preparations from Bidens pilosa L. Colloidal silicon dioxide, β-cyclodextrin, maltodextrin dextrose equivalent (DE) 10, and microcrystalline cellulose were used as drying carriers. The dried product was characterized by the particle size and morphology, total flavonoid content, solubility, flowability, and water activity. High-performance liquid chromatography (HPLC) was used to detect four marker compounds previously reported for this plant. Spray and spouted bed drying systems were compared through energetic efficiency, product recovery, elutriation, and product accumulation. The crystalline state of the powders was assessed by X-ray diffraction. Results showed high degradation rates for total flavonoid content and marker compounds during spouted bed drying. Depending on the drying carrier added to extractive solutions, different degrees of protection from degradation were conferred, and the physical characteristics of the product were changed accordingly. The lowest flavonoid degradation (8.6%) and the higher concentration of marker compounds were obtained using β-cyclodextrin as the drying carrier. Particle size was higher when a blend of Aerosil (Evonik Degussa, Hanau, Germany) and cellulose was employed as the drying carrier. A maximum product recovery of 86.9% was achieved by spray drying and 72.9% by spouted bed drying with the Aerosil : cellulose composition.

Keywords:

• Bidens pilosa L
• Dried extracts
• Microencapsulation
• Phytopharmaceutical preparation
• Spouted bed drying
• Spray drying

ACKNOWLEDGMENTS

The authors acknowledge Dr. Joaquim Adelino de Azevedo Filho (Agronomic Institute of Campinas) for supplying the plant material, Prof. Dr. Milton Groppo for identification of the plant material, the State of São Paulo Research Foundation (FAPESP) for financial support and a fellowship to the first author, and the National Council for Scientific and Technological Development (CNPq) for financial support.

Notes

Notes: Mc, collected mass (g); Xp, moisture content (g); Ws, feed rate (g/min); Cs, composition solid content (g/g); θ, process time (min), M _pf , final inert particle mass (g); M _pi , initial inert particle mass (g); T _ge , inlet gas temperature; T _gs outlet gas temperature; T _amb, ambient temperature determined at the beginning of the drying.

^a Freeze-dried sample set as a reference.

*Significant at p < 0.001. SD: F1 vs. F2, F2 vs. F4, F2 vs. F3; SBD: F1 vs. F2, F2 vs. F3, F2 vs. F4.

*Significant at p < 0.05. SD: F1 vs. F2, F1 vs. F3, F1 vs. F4, F2 vs. F3, F3 vs. F4; SBD: F1 vs. F2, F1 vs. F3, F1 vs. F4, F2 vs. F3, F3 vs. F4.

**Significant at p < 0.05. SD: F1 vs. F3, F1 vs. F4, F2 vs. F4, F3 vs. F4; SBD: F1 vs. F2, F2 vs. F3, F2 vs. F4.