The influence of liquid binder on the liquid mobility and preparation of spherical granules by the process of extrusion/spheronization.
The influence of the type of liquid on the movement of water and the performance of the preparation of pellets by the process of extrusion/spheronization has been studied. Liquid movement was assessed by a pressure membrane technique and by extrusion, while the pellet properties were assessed in the terms of their median size, size range (interquartile range), roundness (by a two-dimensional shape factor) and porosity. The model formulations studied were microcrystalline cellulose (MCC) and mixtures of MCC and barium sulphate at 20, 50 and 80% levels. The liquids were water, a 25% solution of glycerol in water and an anionic surfactant (sodium lauryl sulphate) below its c.m.c. and two concentrations (0.01 and 0.0001%) of a non-ionic surfactant (Pluronic PF68). The presence of the different liquids changed the ease and extent with which the liquid could be removed (drying) and reabsorbed (wetting), resulting in lower levels of saturation with the glycerol solution and considerably increased levels of saturation with the surfactants. Changes in liquid movement during extrusion, were influenced more by the level of liquid and the rate of extrusion, than by its composition. The level of liquid was also an important factor in terms of the force necessary to extrude the different formulations. For a given level of liquid, the glycerol solution tended to increase extrusion force, while the surfactant solutions tended to decrease the extrusion force. The liquid levels, particulate composition and rate of extrusion were important in terms of pellet size, size range, roundness and porosity. The low level of liquid involved produced elongated pellets. The wet formulations produced larger, agglomerated pellets with a wide particle size range and a higher porosity. The lowest porosity pellets were prepared from mixtures with no or a low barium sulphate content while the highest levels of porosity were found with equal parts MCC and barium sulphate. In general, for equivalent liquid contents, pellets made with the glycerol solution were more porous than those prepared with water while the opposite was true for pellets made with surfactants. Although the different liquids influenced water movements, they did not prevent the formation of high quality pellets by the process of extrusion/spheronization.
Boutell
S
S
Department of Pharmaceutics, The School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX, UK.
Newton
J M
JM
Bloor
J R
JR
Hayes
G
G
D000465:Algorithms; D001466:Barium Sulfate / Q000008:administration & dosage / Q000737:chemistry; D002482:Cellulose; D003287:Contrast Media / Q000008:administration & dosage / Q000737:chemistry; D004339:Drug Compounding / Q000379:methods*; D005079:Excipients; D008567:Membranes, Artificial; D010316:Particle Size; D016062:Porosity; D011208:Powders; D011312:Pressure; D012967:Sodium Dodecyl Sulfate; D012995:Solubility; D013500:Surface Tension; D013501:Surface-Active Agents
D003287:Contrast Media; D005079:Excipients; D008567:Membranes, Artificial; D011208:Powders; D013501:Surface-Active Agents; D001466:Barium Sulfate; D012967:Sodium Dodecyl Sulfate; D002482:Cellulose; C109691:microcrystalline cellulose