A smoking article (10) incorporates a liquid release component of a sustained release liquid delivery material (20), the liquid delivery material comprising a closed matrix structure having a polymer matrix defining a plurality of domains. A liquid composition is trapped within the domains and is releasable from the closed matrix structure upon compression of the liquid release component. The polymer matrix is formed of one or more anionic polysaccharides cross-linked by multivalent cations. A filler comprising one or more amphiphilic polysaccharides is incorporated within the polymer matrix. The one or more amphiphilic polysaccharides of the filler are selected from starch chemically modified to be amphiphilic and starch derivatives chemically modified to be amphiphilic.