A Review on Influence of Spray Drying Process Parameters on the Production of Medicinal Plant Powders.

Medicinal plants are used by the 80% of the world population as primary health care andthe phytomedicine market is growing exponentially. Currently, the production of phytopharmaceuticals with proper efficacy, safety and consistent quality constitute a relevant challenge. The dried dosage forms of medicinal plants are preferred than liquid presentations because their higher stability. The spray drying technology is the most employed process to produce dried extracts from medicinal plant liquid extracts. These powders need to meet certain physico-chemical (e.g., moisture content, hygroscopicity, particle size, density, concentration of active ingredients) and mechanical (e.g., flowability and compressibility) properties to be used in a solid pharmaceutical form. In addition, high process yields and good powder quality can be obtained by selecting suitable process parameters: spray drying operating conditions andtype/concentration of carriers (drying co-adjuvants). The optimal process parameters are strongly affected by the chemical nature of the medicinal plant extract. This review aims to give a general guide to understand the effect of the process parameters on the product properties and process yield. This guideline could help practitioners and researchers to initially select the levels of the process variables to decrease thetime and cost of the development stage of medicinal plants powders.