Hydroxypropylmethylcelluloses (HPMC) are cellulose ethers which may be used as the basis for hydrophilic matrices for controlled release oral delivery and offer the advantages of being non-toxic and relatively inexpensive. In this work, we designed new drug release system using HPMC as matrix, manufactured by direct compression technology and have investigated the effects of the controlling factors on drug release from a swellable hydrophillic delivery system. It was found that the release rate of the drug decreased with increasing the polymer molecular weight and the polymer content in tablets, and was independent of compaction pressure and pH of dissolution fluids. Especially, the ability of the anionic surfactant, sodium laurylsulfate, to retard the release of pseudoephedrine hydrochloride from HPMC was characterised. With increasing the concentration of the sodium laurysulfate within the matrix, drug release rate decreased. It is believed that, provided the pseudoephedrine hydrochloride and the sodium laurysulfate are oppositely charged, they will bind together in situ within the HPMC matrix, leading to reduced drug release rates.