The aim of the current study was to prepare a novel co-processed excipient for extended-release tablet dosage form of weakly basic drug. The co-processed excipient was prepared from hydroxypropyl methyl cellulose (HPMC) as a hydrophilic polymer and hydrogenated castor oil (HCO) as a hydrophobic ingredient and anhydrous citric acid as an acidifier. Quetiapine fumarate was selected as model weakly basic drug. Drug-excipients compatibility was studied by differential scanning Calorimetry (DSC) and fourier Transform Infrared (FTIR) studies. The effect of different formulation variables, namely, concentration of co-processed excipient and hardness of the tablet on the in-vitro release was studied using 32factorial design. Stability studies of the optimized formulations was carried out. The prepared co-processed excipient has complied all the established criteria for tablet formulation. There was no interaction seen among excipients while co-processing. The 24-hour dissolution profile of optimized batch and market product was comparable with the f2 value of 69. The short-term stability study shows no significant change in the physical characteristics and drug release pattern. The prepared co-processed excipient is novel and proved as a universal excipient for weakly basic drugs. Method of preparation of co-processed excipient wassolvent evaporation technique and was optimized for lab-scale production. The excipient has excellent flow property as well as compressibility. Any method of tableting from direct compression, wet granulation, and hot-melt extrusion, can be applied as per the necessity.

Co-processed excipient, weakly basic drugs, HPMC, hydrogenated castor oil, anhydrous citric acid.