INVESTIGADORES
RAMIREZ RIGO Maria Veronica
congresos y reuniones científicas
Título:
Development of spray-dried medicinal plant extracts with appropriate physical properties for direct compression.
Autor/es:
GALLO, LC; PIÑA J; ALLEMANDI DA; RAMÍREZ RIGO MV; BUCALÁ V
Lugar:
Rosario
Reunión:
Congreso; II RICIFA; 2012
Institución organizadora:
Universidad Nacional de Rosario
Resumen:
Introduction More than 80% of the pharmaceutical industry production is based on powders in tablet form1. Direct compression (DC) is the most efficient process used for tablet preparation; it offers several advantages such as low labor costs, processing time and energy consumption2. Nevertheless, this technique is limited to powders with good flowability and low segregation tendency. Dried plant extracts (DPEs) are usually used as the therapeutically active ingredient for the manufacture of phytotablets. Generally, DPEs have poor flow properties and compactability; consequently, they cannot be directly compressed3. Therefore, the development of new technologies to obtain DPEs with accurate quality characteristics is an important issue for the herbal industry. In particular, the spray-drying technique is the preferred route due to its capacity to produce powders with precise specifications in continuous operations4. In a previous work and by using a factorial statistical design, Gallo et al.5 found the most efficient set of spray-drying operating conditions to produce a Rhamnus purshianus dried extract with good flowability and compactability for DC, low moisture content and hygroscopicity, and high process yield. The goal of this work was to evaluate the feasibility of spray-drying different plant medicinal extracts using the established set of operating conditions to obtain DPEs with good physical properties for DC and high process yield. Materials and methods The selected medicinal plants were: Hamamelis virginiana L., Centella asiatica L., Hypericum perforatum L., Cynara scolymus L. and Peumus boldus Mol. Table 1 presents their therapeutic effects. Each plant extract was spray-dried in a Mini Spray Dryer Büchi B-290 utilizing colloidal silicon dioxide (SiO2) as drying aid. The experimental conditions were: inlet air temperature 130º C, atomization air volumetric flowrate 400 l/h, feed volumetric flow rate 2 ml/min and drying air volumetric flowrate about 35-38 m3/h. The DPEs were obtained by spray-drying a dispersion constituted by the fluid plant extract and SiO2. The proportion of solid plant residue to SiO2 was 1:1. The process yield (PY) was determined. Two flow powder indicators, the angle of repose (α) and Carr´s Index (CI), as well as the product moisture content (MC) were evaluated. For compacted DPEs, the hardness and disintegration time (DT) was investigated. Results The PY was high (higher than 65%) for all the experiments, being the obtained values more than acceptable for the lab-scale spray-dryer. All the DPEs showed good flow properties and compactability for DC5 (Table 1). The powders moisture contents were lower than 4.4 % (i.e. appropriate levels for spray-dried plant extracts). The compacted DPEs exhibited adequate disintegration times (below 30 min)6, except for P. boldus (Table 1). The compacts of the P. boldus powder also presented the highest hardness values (7.8 kgf), which can be related to their highest DT. The addition of suitable excipients, as desintegrants, during the dried extract tablet formulation could improve the DT7. Conclusions The optimal set of spray-drying operating conditions found for R. purshianus extract was useful to produce DPEs of other medicinal plant extracts with good physical properties for DC and high process yields.