The invention provides a method of sustained delivery of a lactam, imide, amide, sulfonamide, carbamate or urea containing parent drug by administering to a patient an effective amount of a prodrug compound of the invention wherein upon administration to the patient, release of the parent drug from the prodrug is sustained release. The first and second groups of cells may be coupled in series to a DC bus to deliver DC voltage and power to the DC bus. In some embodiments, the generated parser comprises two or more handlers forming a processing pipeline. Thus, only a portion of the user’s concern is extracted from an enormous amount of multimedia information, and individual information is selectively provided in units of users.