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Drug Formula Design Based on Scientific Assessment—BUFFERIN Luna

Menstrual pain accounts for more than 20% of OTC antipyretic analgesic use. Lion has advanced research related to such drugs, particularly seeking to meet the needs of women in their 20s, who commonly say that they want quick pain relief. As a result, Lion developed the BUFFERIN Luna Series, which, as the first OTC medicine in Japan formulated with both ibuprofen and acetaminophen, is both easy on the stomach and highly effective.

Determining the Active Ingredient Content

Pain that originates at the peripheries of the body travels as information to the brain, which then processes the information and “feels” it as pain. Menstrual pain begins when high levels of prostaglandin generated in the uterine lining during a woman’s menstrual period cause the smooth muscle of the uterus to forcefully contract while strongly stimulating the peripheral nerves, which transmit pain signals. This stimulus is transmitted up the central nerves until it reaches the cerebral cortex, where it is registered as lower abdominal or stomach pain.

The most notable feature of BUFFERIN Luna is that it is Japan’s first OTC drug formulated with two active ingredients that have different points of action against such pain. Ibuprofen acts on the peripheral nerves, where the pain signals originate, while acetaminophen suppresses the transmission of pain signals through the central nerves.

To design an active ingredient formula, Lion used an animal model of pain relief to examine the efficacy of multiple formulas. As a result, we found that a 1:1 ratio of ibuprofen and acetaminophen produced a highly synergistic pain relief effect (Figure 1).

Furthermore, we looked into the risk of stomach disorders, the most commonly feared side affect of antipyretic analgesics. Using an animal model, we found that, by pairing acetaminophen with an excessive, disorder-causing dose of ibuprofen at a 1:1 ratio, the resulting stomach disorders were almost eliminated (Figure 2).

The final BUFFERIN Luna formulation includes ibuprofen and acetaminophen as well as allylisopropyl acetylurea (a sedative), which is effective against feelings of irritability and gloominess, and the secondary analgesic ingredient caffeine.

Furthermore, to evaluate the efficacy of BUFFERIN Luna in humans, we partnered with three medical institutions to conduct clinical trials of the product with patients suffering from menstrual pain, headache, or pain after tooth extraction.

Lion’s pharmaceutical product development is aimed at delivering more useful OTC drugs by scientifically examining the effects of drug formulations from various angles and combining technologies for designing highly effective and safe combinations of active ingredients with advanced drug manufacturing technologies. Going forward, Lion will continue to utilize these technologies to advance R&D aimed at helping customers enjoy comfortable, healthy living.

R&D Case Study—Pharmaceutical Products