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Bioequivalence Study of Paracetamol Orodispersible Tablet 500 mg vs Paracetamol Oral Solution 100 mg/mL in Healthy Volunteers (fasted)

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

The trial involves healthy volunteers who will not eat before receiving the medication. The medication being tested is a 500 mg dose of paracetamol in a rapidly dissolving tablet that can be taken without water (an orodispersible tablet) and a 100 mg/ml oral solution of the same drug marketed as Apiretal.

The main purpose of the study is to determine whether the two formulations provide the same amount of drug in the body, a concept known as bioequivalence, which means that the tablet and the liquid give comparable exposure to the medicine.

Participants will receive a single dose of each formulation in a random order, with a period of no medication between doses. All doses are taken while fasting, and blood samples are collected over several hours to measure how much of the medicine appears in the bloodstream, using simple measures such as the total exposure (AUC0-t) and the highest level reached (Cmax). Safety is monitored through basic checks like vital signs and a brief medical examination.

The research process

The trial runs in 9 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Randomization and schedule briefing

    After joining the study you will be assigned a random order for receiving the three study medicines. the order determines which formulation you will take first, second, and third.

    You will receive a written schedule that shows the days when each dose will be taken and the required fasting periods.

  2. Step 2

    Fasting before each dose

    You must not eat or drink anything except water for at least ten hours before each study dose. this is called fasting and it helps ensure accurate measurement of the medicine in your blood.

  3. Step 3

    First dose administration

    On the scheduled day you will receive a single dose of paracetamol worth 500 mg.

    If the assigned formulation is the orodispersible tablet, you will place one 500 mg tablet in your mouth and allow it to dissolve without chewing. the tablet may be taken with a small sip of water if the schedule specifies “with water,” or without water if it specifies “without water.”

    If the assigned formulation is the oral solution, you will be given 5 ml of a liquid that contains 100 mg/ml of paracetamol, providing the same 500 mg dose.

  4. Step 4

    Blood sampling and monitoring after the dose

    Shortly after the dose you will remain in the clinic while staff draw small blood samples at several time points. these samples are used to measure the amount of paracetamol in your blood over time.

    Your vital signs (such as blood pressure and heart rate) will be checked, and an electrocardiogram (ECG) may be performed to monitor heart activity.

    Any side effects you experience will be recorded.

  5. Step 5

    Washout period

    After the last blood sample for the first period you will return to normal eating and drinking.

    A washout period of several days (as indicated in your schedule) will follow before the next dose. the washout allows the previous dose of paracetamol to leave your body completely.

  6. Step 6

    Second dose administration

    You will repeat steps 2, 3, and 4 using the second formulation assigned by the random schedule.

    The same fasting requirement, single 500 mg dose, and monitoring procedures apply.

  7. Step 7

    Second washout period

    After the second set of blood samples you will observe another washout period before the final dose.

  8. Step 8

    Third dose administration

    You will repeat steps 2, 3, and 4 a third time with the remaining formulation.

    The same fasting, single 500 mg dose, and safety monitoring are required.

  9. Step 9

    Final assessments and study completion

    After the last blood sample you will undergo final safety checks, including vital signs, laboratory tests, and an ECG.

    Once all assessments are finished you will be considered to have completed the study.

Who can join the trial?

8 criteria

  • You must be between 18 and 50 years old and can be either male or female.
  • You must be healthy, without any organic (physical) or psychic (mental) conditions.
  • Your medical records and the physical exam done at screening must not show any important problems.
  • Your blood tests (haematology and biochemistry) and screenings for infections (serology for hepatitis B marker HBsAg, hepatitis C antibodies HCV antibodies, and HIV antibodies HIV antibodies) as well as urine drug tests must all be normal.
  • Your vital signs—including blood pressure, breathing rate, body temperature, and pulse rate—and the heart’s electrical test (electrocardiogram) must be without significant abnormalities.
  • Your body weight must give a BMI (body mass index) between 18.5 and 30.0 kg/m², which means your weight relative to your height is in a healthy range.
  • You must agree to use a medically acceptable barrier method of contraception (such as condoms) during the study; hormonal contraceptives and an intrauterine hormone‑releasing system (IUS) are not allowed.
  • You must sign a written informed consent form that has been approved by the study’s ethics committee.

Who cannot join the trial?

16 criteria

  • Allergy or unusual reaction (hypersensitivity) to the study drug or any of its ingredients (including inactive components called excipients).
  • Drinking a lot of caffeine‑containing beverages (more than 5 cups of coffee, tea, chocolate drinks, or cola each day).
  • History of alcohol dependence or illegal drug use in the last 5 years, or drinking more than 40 grams of alcohol per day for men or 24 grams per day for women.
  • Taking any medication within 14 days before the study (except short‑term ibuprofen if the doctor allows) or using any over‑the‑counter products, vitamins, or herbal supplements within 7 days before the study.
  • Positive test for hepatitis B surface antigen, hepatitis C antibody, or HIV infection.
  • Positive result for illegal drugs in a urine test or for alcohol in a breath test on the first day of the study.
  • Having any ongoing disease of the heart (cardiovascular), lungs (respiratory), kidneys (renal), liver (hepatic), hormones (endocrine), stomach/intestines (gastrointestinal), blood (haematological), nerves (neurological), or any other long‑term illness.
  • Women who are pregnant or breastfeeding.
  • Smoking any tobacco or using nicotine products (including e‑cigarettes, patches, or smokeless tobacco) within the past 6 months.
  • Participating in another clinical trial in the 3 months before this study.
  • Donating blood within the 4 weeks before the screening visit.
  • Having major surgery in the past 6 months or having planned surgery during the study period.
  • Being mentally or legally unable to give informed consent.
  • Unwillingness or inability to follow the study procedures.
  • Difficulty understanding the language in which the study information is provided.
  • Any other condition that the investigator believes could put the participant’s health at risk or affect the conduct of the trial.
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Investigated drugs

  • Paracetamol orodispersible tablet

    is a tablet that melts in the mouth without needing water. It contains paracetamol and provides a dose of 500 mg. In the study, healthy volunteers take this tablet on an empty stomach, and researchers measure how quickly and how much of the drug reaches the bloodstream.

  • Paracetamol oral solution

    is a liquid form of paracetamol, with a concentration of 100 mg per milliliter. When the correct amount is measured, it also delivers a 500 mg dose. Participants drink this solution while fasting, and it serves as the reference product to compare the absorption of the tablet.

What is already known about the treatment

  • Apiretal 500 mg comprimidos bucodispersables

    This medication is a 500 mg orodispersible tablet that is placed in the mouth and allowed to dissolve, with or without water, for buccal (mouth) use. Paracetamol, the active ingredient, is an over‑the‑counter pain reliever and fever reducer that is well established in medical literature and everyday practice. It is mainly used to treat mild to moderate pain such as headaches, toothaches, and to lower fever. The drug works by blocking the COX enzymes, which reduces the production of prostaglandins that cause pain and raise body temperature, and it belongs to the analgesic‑antipyretic class.

  • Apiretal 100 mg/ml solución oral

    This product is a liquid oral solution containing 100 mg/ml of paracetamol, taken by swallowing the measured dose for oral use. Paracetamol is a widely used, approved medication with a long history of safety and efficacy in treating pain and fever. It is indicated for relief of mild to moderate aches, pains, and for reducing fever in children and adults. The molecule works by inhibiting COX enzymes, lowering prostaglandin levels, and it is classified as an analgesic‑antipyretic.

Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase ITrial ID2023-504815-34-00Protocol codeBESPA-ODTEstimated enrolment24 patientsSponsorLaboratorios Ern S.A.

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