Engineering spray-dried rosemary extracts with improved physicomechanical properties: a design of experiments issue

ABSTRACT A 33 Box–Behnken design and Response Surface Methodology were performed to evaluate the influence of extract feed rate, drying air inlet temperature and spray nozzle airflow rate on the process yield, stability parameters (moisture content and water activity) and on several physicomechanical properties of spray-dried rosemary extracts. Powder yield ranged from 17.1 to 74.96%. The spray-dried rosemary extracts showed moisture content and water activity below 5% and 0.5%, respectively, which indicate their chemical and microbiological stabilities. Even without using drying aids, some sets of experimental conditions rendered dried products with suitable flowability and compressibility characteristics for direct preparation of solid dosage forms. Analysis of variance and Response Surface Methodology proved that studied factors significantly affected most of the spray-dried rosemary extract quality indicators at different levels. The main processing parameter affecting the spray-dried rosemary extract characteristics was inlet temperature. The best combination of parameters used to obtain a reasonable yield of stable dry rosemary extracts with adequate technological properties for pharmaceutical purpose involves an extract feed rate of 2 ml/min, 80 °C inlet temperature and 40 l/min SA. The design of experiments approach is an interesting strategy for engineering spray-dried rosemary extracts with improved characteristics for pharmaceutical industrial purpose.

Optimization of the extraction of curcumin from Curcuma longa rhizomes

The aim of this work was to study the effect of dynamic maceration factors upon the curcumin content of Curcuma longa L., Zingiberaceae, extracts and to determine the optimum set of parameters for the extraction of curcumin using a 2(5) full factorial design and the response surface methodology. Under the established conditions, the content of soluble solids and curcumin in the extracts ranged from 0.8 to 3.4%, and from 0.1 to 1.8%, respectively. The most influential variable observed for the extraction was the ethanolic strength of the solvent. The optimized condition involves an extraction time of 12 h, agitation speed of 30 rpm, drug to solvent ratio of 1/6, extraction temperature of 80 ºC and the solvent with ethanolic strength of 70%. The data reported herein are useful for further developments of curcuma phytopharmaceutical intermediate products with optimized characteristics.

Spray drying of Eugenia dysenterica extract: effects of in-process parameters on product quality

A 2³ full factorial design was used to assess the impact of spraying air flow rate (30-50 L/min), drying air inlet temperature (90-150 ºC) and extract feed rate (4-6 g/min) on the quality of Eugenia dysenterica DC., Myrtaceae, spray-dried extracts. Response surface methodology (RSM) was applied to analyze the significance of the effects of process factors on product quality and to obtain fitted equations to predict dry powder properties. Powder yields were satisfactory, ranging from 34.64 to 63.92%. The dried products showed moisture contents and water activities below 5% and 0.5, respectively. The recuperation ratios of total polyphenols, tannins and flavonoids ranged from 88.66 to 99.07%, 70.38 to 81.87% and 74.51 to 98.68%, respectively. Additionally, in some conditions the parameters related to dry product’s flowability and compressibility varied over a range acceptable for pharmaceutical purposes. RSM proved that studied factors significantly affected most of the quality indicators at different levels. The spray drying technology is an attractive and promising alternative for the development of intermediate phytopharmaceutical products of E. dysenterica.