An object of the present invention is to provide a kidney-targeting drug delivery agent which is composed of bioabsorbable materials, transiently accumulates in a kidney and particularly kidney functional units such as tubular epithelial cells for a short period of time, and does not remain in the kidney for a prolonged time after accumulation. The application agent may be associated with a 1-8YY toll-free number or other national or international telephone number. The left and right guide arms 50 and 60 are formed with symmetrical structures so that they are interchangeable between the left and right sides. The CHARi field performs control of the data transmission by supplying control fields including a multimedia event index and data fields in the user data.