Provided is an apparatus and method for coding and decoding multi-object audio signals with various channels and providing backward compatibility with a conventional spatial audio coding bitstream. The dosage forms of the invention sustain the release of the therapeutically active agent from about 4 to about 24 hours when said dosage form is exposed to aqueous solutions. The pad may be rectangular or square shape or substantially circular in shape. Thus, the trigger cannot turn even if the same is pulled.