Porous cellulose matrices containing lipophilic release modifiers - a potential oral extended-release system

A multiple-unit extended-release matrix preparation was prepared by the inc orporation of a hydrophilic drug (paracetamol) and lipophilic release modif iers (cetyl alcohol and paraffin) into porous cellulose matrices. The incor poration was performed using a one-step melt method. The in vitro drug rele ase could be extended up to at least 16 h. The release rate could be contro lled by varying the ratio of cetyl alcohol to paraffin. The porosity of the matrix during release increased to a larger extent than explainable by dis solution of the drug substance. This increase in porosity appears to be cau sed by swelling of the cellulose in combination with some erosion of the ma trix material. (C) 1999 Elsevier Science B.V. All rights reserved.