Force-displacement parameters of maltodextrins after the addition of lubricants

The effect of the presence of lubricants on the tableting properties of Maltrin(R) M510 and M150 was examined using an instrumented single punch tablet press. The lubricants studied were the classical magnesium stearate as well as PRUV(R) and PRECIROL(R). The energy balance parameters have been discussed in relation with the three lubricants and the conditions established in the study (concentration of lubricant, mixing time and applied pressure). The expansion work and the net apparent work did not distinguish between both maltodextrins. Although M150 presented more capacity to form compacts than M510, it showed higher friction during compression. The addition of lubricants decreased the friction work and increased the expansion work. The bonding characteristics indicated that PRECIROL(R) was the lubricant that disminshed it to a greater extent, probably due to its morphological properties. It presents a small size in comparison with the other two lubricants under study and occupied more places between particles. The effect of concentration and mixing time was variable and different for both maltodextrins due to a slightly insensitivity showed by M150. The higher the applied pressure was, the higher expansion and net apparent work was obtained, showing a linear regression. When the expression for friction work proposed by Juslin was considered, the regression fit was better than with de Blaey's equation. The study of plasticity in relation with applied pressure showed that over 100 MPa there was a limit of plastic deformation for these maltodextrins. (C) 1997 Elsevier Science B.V.