An oral controlled matrix tablet of Metformin HCl was formulated by hydrophilic polymer such as hydroxy propyl methyl cellulose K100 M (HPMC K100 M) as rate retarding polymer along with pharmaceutically acceptable electrolytes. Electrolytes such as aluminium hydroxide, magnesium carbonate and sodium carbonate were used at different concentrations (40 to 60 mg / tablet) in various formulations, while the ratio of drug and polymer were maintained constantly. In this work, a attempt was made for in-situ interactions between drug and electrolytes to control the release of highly water soluble drug from oral hydrophilic monolithic system. These electrolytes were used to monitor matrix swelling and gel properties. Electrolytes at higher concentrations exhibited greater retardation in drug release from than in low concentrations for controlled release of the drug. The results indicated that the drug released at a controlled rate were due to differential swelling rate and matrix stiffening and provides a uniform gel layer. These findings indicated that the swelling and gel formation in the presence of ionisable species within the hydrophilic matrices provide an attractive alternative for controlled drug delivery from a monolithic system. Accelerated stability studies were carried out as per ICH guidelines for some selected formulations, which indicated that these formulations were stable at accelerated storage conditions.