THE ROLE OF COLLOIDAL SILICON DIOXIDE IN THE ENHANCEMENT OF THE DRYING OF HERBAL PREPARATIONS IN SUSPENDED STATE

Recently, some research groups have been developing studies aiming to apply spouted beds of inert particles for production of dried herbal extracts. However, mainly due to their complex composition, several problems arise during the spouted bed drying of herbal extracts such as bed instability, product accumulation, particle agglomeration, and bed collapse. The addition of drying carriers, like colloidal silicon dioxide, to the extractive solution can minimize these unwanted effects. The aim of this work was to study the influence of the addition of colloidal silicon dioxide on enhancement of the performance of the drying of hydroalcoholic extract of Bauhinia forficata Link on a spouted bed of inert particles. The physical properties of the herbal extract and of its mixture with colloidal silicon dioxide at several concentrations (20% to 80% related to solids content) were quantified by determination of the surface tension, rheological properties, density, pH, and contact angles with the inert surfaces. Drying performance was evaluated through determination of the elutriation ratio, product recovery ratio, and product accumulation. The product was characterized through determination of the thermal degradation of bioactive compounds and product moisture content. The results indicated that the rheological properties of the extracts and their preparations, the contact angle with inert material, and the work of adhesion play important roles in the spouted bed drying of herbal extracts. Higher concentration of the drying carrier significantly improved the spouted bed drying performance.

Evaluation of the spouted bed dried leaf extract of Bauhinia forficata for the treatment of experimental diabetes in rats

Previously, we have demonstrated that treatment of experimental diabetes with a decoction of Bauhinia forficata leaves is beneficial. In this study, we prepared a two-fold concentrate of this extract and tested its effects on physiological, biochemical and toxicity markers in streptozotocin-diabetic rats. Dried and ground leaves were extracted with warm 70% hydroethanol and the filtrate concentrated by evaporation at 50 degrees C. This solution was mixed with colloidal silicon dioxide (Tixosil-333 (R)) and dried in a spouted bed (BfT). Rats were treated with water, insulin and Tixosil particles at low or high doses, alone or coated with dried BfT. Animals were periodically weighed and monitored for water and food intake; urinary volume, glucose, urea and protein; blood glucose, serum lipids, liver toxicity markers transaminase and phosphatase and masses of adipose tissue and skeletal muscle. Insulin treatment gave best rat growth and lowest values for all other markers. No other treatment affected any diabetic marker, but the enzyme activities were changed by diabetes and BfT. Thus, BfT toxicity could arise from secondary products of plant constituents or Tixosil interaction. Therefore, BfT prepared in the spouted bed as described, is unsuitable for treatment of diabetes, which implies that the method of preparation of any medicine is critical for its efficacy and toxicity.

The Preparation of Ternary Solid Dispersions of an Herbal Drug via Spray Drying of Liquid Feed

The present study aimed the preparation and characterization of ternary solid dispersions by direct spray drying of a liquid suspension containing curcumin, a solubility enhancer and a drying aid. The experiments followed a Box-Behnken design in order to evaluate the influence of temperature, ratio of curcumin: lipidic carrier, and the collodial silicon dioxide content on the characteristics of the microparticulated solid dispersions. The angle of repose, Hausner factor, Carr index, water activity, and solubility were used to characterize solid dispersions. The results show that water activity, Hausner factor, and Carr index varied in an acceptable range for pharmaceutical purposes. The condition that maximizes solubility was determined using an exploratory design based on a surface response analysis and allowed a 3200-fold increase in curcumin solubility. Ternary solid dispersion showed a 90% curcumin release after 10min during a dissolution test. The results show that the spray drying of a liquid feed is an attractive and promising alternative to obtain enhanced solubility drug ternary solid dispersions.

DRYING OF HERBAL EXTRACT IN A DRAFT-TUBE SPOUTED BED

This work evaluates the feasibility of the draft-tube spouted bed for drying of herbal extract. Drying runs were carried out according to a central composite design in a conical-cylindrical draft-tube spouted bed. The variables studied were the percentage of the drying aid (ADJ), the drying gas flow rate relative to gas flow at minimum spouting (Q/Q(ms)), and the flow rate of extract fed to the system relative to the spouting gas flow rate W(s)/W(g)). Colloidal silicon dioxide was the drying aid used in order to improve drying performance. Statistical analysis of the effects of processing parameters on product recovery, product accumulation in the bed, and product properties permitted the identification of parameters presenting significant effects on drying. Optimized drying conditions were related to experimental parameters as follow: high levels of the percentage of drying adjuvant (ADJ), high airflow rate relative to minimum spouting (Q/Q(ms)), and low values of the feed flow rate of the extract relative to the gas flow rate (W(s)/W(g)).

Stability and compatibility study on enalapril maleate using thermoanalytical techniques

This paper demonstrates the application of thermal analysis in compatibility and stability studies between it ACE inhibitor (enalapril maleate) and excipients. The results have helped to elucidate the reason of a stability problem observed (luring the storage of enalapril maleate tablets. Incompatibility between enalapril maleate and colloidal silicon dioxide was detected. Besides, it was confirmed that the reaction between enalapril maleate and NaHCO3 increases the thermal stability of the drug. This Study Supports the importance of using thermoanalytical methods in the development of pharmaceuticals.