C. R. F. Souza

Processing of Rosmarinus officinalis linne extract on spray and spouted bed dryers

Abstract - This article presents an investigation of the potential of spray and spouted bed technology for the production of dried extracts of Rosmarinus officinalis Linne, popularly known as rosemary . The extractive solution was characterized by loss on drying, extractable matter and total phenolic and flavonoid compounds (chemical markers). The product was characterized by determination of loss on drying, size distribution, morphology, flow properties and thermal degradation and thermal behavior. The spray and spouted bed dryer performance were assessed through estimation of thermal efficiency, product accumulation and product recovery. The parameters studied were the inlet temperature of the spouting gas (80 and 150 o C) and the feed mass flow rate of concentrated extract relative to the evaporation capacity of the dryer, W s /W max (15 to 75%). The atomizing air flow rate was maintained at 20 l/min with a pressure of 196.1 kPa. The spouting gas flow rate used in the drying runs was 40% higher than the gas flow under the condition of minimum spouting. The spray drying gas flow rate was fixed at 0.0118 kg/s. Under the conditions studied, performance in the spray and spouted bed drying of

Spouted bed drying of Bauhinia forficata link extract: the effects of feed atomizer position and operating conditions on equipment performance and product properties

In this paper the effects of feed atomizer position and operating conditions on equipment performance (accumulation rate, product recovery, elutriation and thermal efficiency) and product properties (moisture content, size distribution, flavonoid degradation and flow properties) during spouted bed drying of Bauhinia forficata Link extract are evaluated. The parameters studied were the position of the atomizer system (top spray or bottom spray), the inlet temperature of the spouting gas (80 and 150oC) and the feed mass flow rate of concentrated extract relative to the evaporation capacity of the dryer, Ws/Wmax (15 to 100%). Higher accumulation rate values were obtained with the atomizer placed at the bottom of the bed. In this configuration, the accumulation rate increases with the increase in the Ws/Wmax ratio. The best drying performance was obtained for the top spray configuration.

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.

Spouted Bed Drying as a Method for Enzyme Immobilization

Usually immobilization is a requirement for the use of enzymes as an industrial biocatalyst. In this work, endophytic fungus Cercospora kikuchii lipase was immobilized by covalent binding on agricultural by-products and microcrystalline cellulose. The enzyme support system was submitted to spouted bed drying. Lipase immobilized on microcrystalline cellulose with 1.5% of glutaraldehyde showed the best results, presenting 179.1% of the original activity after drying, followed by rice husk (173.9%), corn stover (169.8%), sugarcane bagasse (157.3%), green coconut fiber (102.3%), and corncob (99.8%). The immobilized derivatives obtained showed a decreased enzyme activity with an average of only 17.31%, whereas the enzyme in its free form lost 85.8% of its initial activity after storage for 6 months. The operational stability showed that the biocatalysts prepared retained an average of 67.2% of the initial activity after five reuse cycles. The results showed that the use of agricultural by-products as low-cost support material associated with the spouted bed drying is promising and can contribute to industrial application of biocatalysts.

In Vitro Dissolution Studies of Sodium Diclofenac Granules Coated with Eudragit L-30D-55® by Fluidized-Bed System

Abstract The objective of this work was to study the dissolution process of sodium diclofenac granules coated with a polymeric suspension of Eudragit L-30D-55® by fluidized bed. Methacrylic acid-methylmetacrylate copolymer, also known as Eudragit, has been used as a pH sensitive coating material to protect drug substances prior to delivery to the human intestines. The sodium diclofenac granules were prepared by wet granulation technology using microcrystalline cellulose (MICROCEL), sodium diclofenac, and polivinilpirrolidone K-30. The granules coating operation was carried out in a fluidized bed with top spraying by a double-fluid nozzle. The dissolutions studies of the coated granules were performed in triplicate in a dissolution test station according to “in vitro testing requirements” Method A (paddle method, rotation of 100 RPM and temperature fixed at 37°C). The dissolution mediums were 0.1N HCl solution and a pH 6.8 phosphate buffer solution, following the pH change dissolution procedure specified in USP for enteric-coated articles: 2 h of exposure to 750 mL of 0.1N HCl followed by testing in 1000 mL of pH 6.8 phosphate buffer, the pH being adjusted with 250 mL of 0.2 M tribasic sodium phosphate solution. The released amount of sodium diclofenac was periodically determined by UV spectrophotometry at wavelength of 276 nm, using a spectrophotometer UV-VIS HP 8453. The coated product showed gastric resistance properties confirming the feasibility of the fluidized bed for applying enteric coating in granules and pharmaceutical powders.

Surfactant Mediated Extraction of Antioxidants from Syzygium aromaticum

In the present study surfactant mediated extraction has been investigated for the extraction of antioxidants from clove flower buds (Syzygium aromaticum). The advantage of this technique is the replacement of organic solvents or other toxic substances by surfactants that could be part of a formulation. The influence of the Hydrophilic Lipophylic Balance (HLB) on extraction was examined in the range of 4.3 to 15 by the mixture of two commonly used surfactants in pharmaceutical and food applications (Tween 80 and Span 80). The effect of the surfactant concentration (2, 5, and 10%) was also evaluated. Results showed that higher HLB values improved eugenol and polyphenols extraction, which could be correlated with the in vitro antioxidant activity. Surfactant concentration of 5% (w/w) showed to be more effective than 2% and there were no significant differences between the results obtained at concentrations of 5 and 10%. The effect of the pH was also investigated on Tween 80 solutions and results showed that increases on the pH value improved the eugenol extraction.

Physicochemical and antioxidant properties of spray dried preparations from Psidium guajava L

This work evaluated the antioxidant activity and physicochemical properties of spray dried preparations (SDP) from leaves of Psidium guajava L. Different drying carriers, namely: maltodextrin, colloidal silicon dioxide, Arabic gum and β-cyclodextrin at concentrations of 40 and 80% relative to solids content were added to drying composition. SDP were characterized through determination of the total phenolic, tannins and flavonoid content. Antioxidant activity of the SDP was assessed by two assays: cellular test that measure the luminol-enhanced chemiluminescence (LumCL) produced by neutrophils stimulated with phorbol myristate acetate (PMA) and the DPPH radical scavenging. SDP containing 40% of maltodextrin showed the best result with respect to total phenolics (18.09% w/w), tannins (10.21% w/w) and flavonoid contents (16.56% w/w). SDP were effective inhibitors of the PMA-stimulated neutrophil function [IC50 (in µg/106cells) ranging from 5.42 to 6.50 µg/mL. LumCL (IC50 of quercetin=1.67 µg/mL]. SDP showed antioxidant activities (IC50) ranging from 6.16 to 10.31 µg/mL by the DPPH method (IC50 of quercetin=0.96 µg/mL). The neutrophil reactive oxygen species generation, triggered by PMA and assessed by luminol was inhibited by SDP in a concentration-dependent manner, with insignificant toxicity to the cells under the tested conditions. Two chemical markers, catechin and quercetin which could be used in the monitoring of the quality of SDP were identified. Structural information of the compounds was obtained from the retention times, UV and mass spectra. In conclusion, SDP from Psidium guajava presented significant antioxidant activity with high potential as an active phytopharmaceutical ingredient for herbal medicine.