Recently, in many medical facilities, generic drugs have replaced name-brand drugs for the purpose of reducing medical expenses. Adhesive tape containing 20 mg ketoprofen (KP) as the active ingredient is categorized as a nonsteroidal, anti-inflammatory drug for external use. To assess the difference in quality between a genuine KP tape and three generic substitutes, we attempted to investigate the permeability of KP through rat or human skin. The permeability of KP using genuine KP tape was about four times greater than two generic KP tapes in rats. Residuum of KP in the genuine KP tape applied to human skin after 24 hours was 36.0%±10.5%, which was significantly less than the residuum of the two generic KP tapes. Since the KP content of the generic drugs was greater than that of the genuine drug, the difference in permeability between genuine KP tape and generic tape may be caused by the form, ingredient, dosage form design, or base.
The present study demonstrated a significant difference in the permeability of KP between name-brand and generic adhesive tapes. These results suggested that the evaluation of permeability or pharmaceutical properties with external use of drugs was useful method when the assessment of the biological equivalent was difficult.
Buprenorphine hydrochloride (BP) is a semi-synthetic opiate derived from the morphine precursor thebaine which has been used as a replacement therapy for opiate dependence. Conventionally, BP is widely used as a parenteral injection for postoperative pain and cancerous pain. However, the injection is not preferable for the cases of intractable chronic pain such as cancerous pain, because frequent administration is needed, considerable pain accompanies injection, and treatment at home is not possible. On the other hand, when BP is orally administered it is metabolized quickly in the liver, and a satisfactory analgesic effect is not expected in its oral dosage form. With this background, the development of BP suppositories has been keenly desired.
The characteristic of developed BP suppositories is to formulate propylene glycol (PG) as an additive. The present study suggested that PG improved rectal absorption of BP and relieved the irritative effect on rectal membrane of BP suppositories without PG. In addition, it became possible to manufacture excellent BP suppositories uniform in content by dissolving BP in a suppository base.