Development of hot-melt extrusion as a novel technique for the ...

disintegrants by absorbing water and the subsequent swelling leads to separation of the tabletparticles. In contrast, XL10, XL and croscarmellose promote wicking via capillary action dueto their high porosity. Subsequently, water is rapidly absorbed and disrupts the interparticularmatrix bonds causing the tablet to fall apart [33] .The superdisintegrant concentration versus the compaction force profiles in Fig.3.4(a-d) showed interesting results regarding the disintegration time performance of eachsuperdisintegrant. At first, it can be seen that XL10 outperformed all superdisintegrants atlow levels (2-5% wt/wt) while XL outperformed at high levels (10-20% w/w) respectively.The disintegration performance can be arranged in descending order for low levels asfollows: XL10>XL>Vivasol>CL-SF>CL, while for high levels the order isXL>XL10>Vivasol>CL-SF>CL. For XL10 the optimum concentration level was between 5-10% w/w with disintegration times varying between 8-20 sec while for 20% w/wdisintegration times were increased without exceeding 60sec. On the other hand, XL‘soptimum level was at 10–20% (wt/wt) showing substantial reduction to the disintegrationtimes (Fig. 3.4C). The better performance of XL10 at low levels can be attributed to thesmaller particle size of XL10 (30-50µm) compared to XL (100-130 µm) facilitating fasterwater absorbance. On the contrary, high XL10 levels led to increased disintegration times.Vivasol showed good disintegration times at high levels (10-20% wt/wt) and betterdisintegration times at compaction forces of 10-20 kN. Interestingly the addition of KollidonCL–SF presented excellent disintegration times at concentrations of 2% w/w withcompaction forces of 8 or 12 kN. This also could be attributed to the particles morphologyfacilitatiung faster water absorptions.Further addition of CL – SF amounts led to prolonged disintegration times but muchlower than 60 sec. In contrast, the Kollidon CL grade showed poor performance for allconcentrations and the entire range of compaction forces. This behaviour can be explained tosome extent because of the small CL–SF (10-30µm) particle size compared to the CL grade(110 – 130µm) similar to the other two crosslinked N-Vinylpyrrolidone grades (XL, XL10).However, the different disintegration times of the five superdisintegrants are mainlyattributed to the different disintegration mechanisms and the tablet porosities. ThePolyplasdone (XL10, XL) and Vivasol grades posses both swelling and wicking properties.All the disintegration studies were carried out at pH 5.6, where these cross-linked polymershave similar swelling capacities (92, 90 and 85% respectively).52 | P a g e