Kumud Padhee, Dr.K.A.Chowdhary, Dr. SatyaNarayan Pattnaik3, Sangram Keshari Sahoo, Naveen Pathak
Today, the scenario of pharmaceutical drug delivery is changing from conventional dosage form to novel drug delivery system with main objective of patient compliance. The main objective of the present study was to develop a multiple-unit, extended drug delivery system for prolong drug release through out the day. Verapamil HCL is an antihypertensive drug, having pH dependent solubility and is being used successfully for the treatment of hypertension and other cardiovascular diseases; hence it was used as a model drug. Weakly basic drugs or salts thereof demonstrate pH-dependent solubility. The resulting release from the conventional matrix system decreases with increasing pH of the gastrointestinal tract. Present study involves development of a multiparticulate drug delivery system to overcome this problem and to achieve pHindependent drug release. In this research work Organic acids such as fumaric & malic acid were added to the drug–polymer system were added as a pH-adjuster inside the pellet core for the maintenance of constant acidic micro-environment inside the core of dosage form. Pelletization technique was selected for the formulation of verapamil HCL to reduce the inter individual variations in plasma levels. PH-independent drug release was achieved from pellets consisting of organic acid in their core when coated with selected pH-independent coating polymers like ethylcellucose, hydroxypropylmethyl cellulose and Eudragit. Organic acids are pH-adjuster at higher pH. Therefore, they are able to compensate the poor solubility of weakly basic drugs at high pH. This approach was successful when using organic acids that demonstrated creating an acidic
