A new study has found that a generic version of the anti-platelet drug Cilostazol is not bioequivalent to the innovator drug.
Bioequivalence is an important pharmacokinetic parameter that indicates whether two proprietary preparations of the same drug are equal or exert the same effect in terms of efficacy and safety.
If two products are found to be bioequivalent, it means that they would be expected to be, for all intents and purposes, the same.
Cilostazol is a medication that inhibits platelet aggregation and widens (dilates) the arteries supplying blood to the legs. It is manufactured by Otsuka Pharmaceutical Co. of Japan.
Cilostazol is used to alleviate symptoms of intermittent claudication in individuals with peripheral artery disease (PAD).
At least half of people who have PAD don’t have any signs or symptoms of the disease. Those who do have signs or symptoms may have pain when walking or climbing stairs, which may be relieved after resting. This pain is called intermittent claudication.
Blood brings oxygen to the muscles; during physical activity or exercise, muscles need more blood. If there is a blockage in the blood vessels, muscles will not get enough blood.
A hallmark of intermittent claudication is that a brief rest relieves the muscle pain because muscles at rest require less blood flow; resumption of physical activity triggers pain recurrence.
Intermittent claudication is more likely to develop in people who also have atherosclerosis in other arteries, such as the heart and brain.
Atherosclerosis is the hardening and narrowing of arteries due to the formation of cholesterol plaques. About 10 percent of people with PAD have intermittent claudication.
Other signs and symptoms of PAD include:
• Pain, numbness, aching, and heaviness in the muscles;
• Cramping in the legs, thighs, calves, and feet;
• A weak or absent pulse in the legs or feet;
• Sores or wounds on toes, feet, or legs that heal slowly, poorly, or not at all;
• Color changes in skin, paleness, or blueness (called cyanosis);
• A decreased temperature in one leg compared to the other leg;
• Poor nail growth and decreased hair growth on toes and legs; and
• Erectile dysfunction, especially among people with diabetes.
The bioavailability study was conducted from Feb. 29 to March 15 at the University of Santo Tomas Center for Drug Research, Evaluation and Studies (UST CeDRES) located at the Clinical Division of the UST Hospital.
It compared the bioavailability of the generic drug product to the innovator product following a single-dose administration.
The study involved 12 healthy male volunteers who were each given either one 100mg tablet of the generic drug or 100mg tablet of the innovator drug according to a randomized dosing sequence.
Eighteen blood samples were drawn from the subjects in 30-minute increments post-drug intake.
The subjects’ vital signs were monitored at pre-specified intervals throughout the blood collection period.
Plasma collected from the blood samples were analyzed for Cilostazol concentration using a validated laboratory analysis method.
The blood analysis revealed that all bioavailability parameters of 100mg tablet of the generic drug were inferior to those of 100mg tablet of the innovator drug.
“On the basis of the findings therefore, the generic drug product, 100mg tablet, is not bioequivalent to the reference/innovator drug product Pletaal‚ 100mg tablet,” concluded William D. Torres, principal investigator for the bioavailability study.