The effect of porous calcium silicate (Florite R) and microcryst. cellulose (Avicel PH 102) on the physicochem. characterizations and dissoln. rate of lidocaine (LD) and consequently the effect on the in vitro release of LD from some suppository bases was studied.  The solid dispersions (sorbates) of LD with the previous adsorbents were prepd. by the solvent deposition method.  The characterizations of sorbates were established by x-​ray, DTA and IR-​spectroscopy.  The x-​ray diffraction results indicate reducing the crystallinity of LD.  The thermograms of DTA indicate a weak and reversible endothermic interaction between LD and the previous adsorbents.  The dissoln. rate of LD from its phys. mixts. and sorbates, in various ratios (1:1, 3:2, 4:1 and 9:1 wt.​/wt.) were studied.  The LD​/Florite R sorbate in 3:2 wt.​/wt. ratio achieved the best dissoln. rate.  In vitro release of LD from some water-​sol. bases (polyethylene glycols) and fatty bases (Witepsol H 15 and Suppocires AM and CM) was studied by using a diffusion cell with artificial membrane at 37°.  The release of LD was significantly faster from water-​sol. bases contg. LD​/Avicel PH 102 sorbate.  Increasing the proportion of low mol. wt. polyethylene glycols in the suppository formulation had greater effect on the rate and extent of release and diffusion of the drug through the membrane.