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Bioavailability Study of Lidocaine Vitamin C Lozenge (drug combination) in Healthy Volunteers

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 examines lozenges that contain a combination of amylmetacresol, dichlorobenzyl alcohol, lidocaine and vitamin C. These are compared with two existing lozenge products that contain the same ingredients except for one component: one product has vitamin C without lidocaine, and the other has lidocaine without vitamin C. The lozenge is a small tablet that dissolves in the mouth, releasing the medicine.

The aim of the study is to evaluate the bioavailability of the ingredients, meaning how much of each substance reaches the part of the body where it can work. Healthy adult volunteers will take a single dose of each lozenge on separate days while fasting. After each dose, samples will be collected to see how quickly and how much of the ingredients are absorbed. The study involves only a short series of visits and does not include any ongoing treatment.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial Study Visit

    You attend the first study visit after joining the trial. During this visit you receive written information about the study, sign the consent form, and are assigned a random order in which you will take the three different lozenges. The study uses a crossover design, meaning you will receive each lozenge type at separate times.

    The study staff explains the requirement to be in a fasting condition before each dose, which means you must not eat or drink anything except water for a specified period before taking the lozenge.

  2. Step 2

    First Dose Administration

    After the required fasting period, you take the first lozenge assigned by the randomisation schedule. The lozenge is taken orally and you allow it to dissolve slowly in the mouth.

    The dose is one lozenge (1 DF dosage form) containing the active substances specified for that product. No other medication is taken at the same time.

  3. Step 3

    Washout Period

    You wait for a washout period as instructed by the study team. This interval allows the previous lozenge to be cleared from your body before the next dose.

    During the washout period you may resume normal eating and drinking, unless other restrictions are given.

  4. Step 4

    Second Dose Administration

    You again observe the fasting condition and then take the second lozenge according to the randomised order. The lozenge is taken orally, one at a time, and allowed to dissolve in the mouth.

    The dose is one lozenge (1 DF dosage form) of the comparator product, which contains amylmetacresol, ascorbic acid, sodium ascorbate, and 2,4 dichlorobenzyl alcohol.

  5. Step 5

    Washout Period

    You observe another washout interval as instructed before the final dose. The purpose is the same as previously described.

  6. Step 6

    Third Dose Administration

    Following the required fasting, you take the third lozenge. This lozenge contains amylmetacresol, 2,4 dichlorobenzyl alcohol, and lidocaine hydrochloride.

    Again, the dose is one lozenge (1 DF dosage form) taken orally and allowed to dissolve in the mouth.

  7. Step 7

    Study Completion

    After the final dose you attend a closing visit where any remaining study materials are returned and final observations are recorded.

    No further medication is required, and you are free to resume your usual activities.

Who can join the trial?

5 criteria

  • You must give written consent after the study team explains the purpose, possible risks, and that you can stop at any time.
  • You need to be between 18 and 45 years old.
  • You must be a non‑smoker (you do not currently smoke cigarettes or other tobacco products).
  • Your body mass index (BMI) – a calculation using weight and height to estimate body size – must be between 18.5 and 30.0.
  • You can be either male or female and must be a healthy volunteer (no serious medical conditions).

Who cannot join the trial?

14 criteria

  • Pregnant or breastfeeding women: Anyone who is pregnant (a positive urine pregnancy test) or nursing a baby cannot join.
  • Recent or heavy alcohol use: People who have had alcohol poisoning in the last 6 months, or who regularly drink more than two standard drinks per day (about a small glass of wine, a large beer, or a shot of strong liquor) are excluded.
  • Positive drug screening: If a test shows the presence of cannabis, opiates, cocaine, or amphetamines, the person cannot participate.
  • Positive blood test for hepatitis B, hepatitis C, or HIV: A test that shows infection with these viruses disqualifies a volunteer.
  • Legal or administrative restrictions on freedom: People who are under court orders, probation, or similar legal constraints cannot be enrolled.
  • Inability to follow study instructions: Anyone who cannot understand or cooperate with the study procedures is excluded.
  • Significant medical or mental health conditions: Ongoing serious physical or mental illnesses, or abnormal lab results indicating kidney or liver problems (for example, liver enzymes GOT, GPT, GGT more than 2.5 times the normal limit, or total bilirubin higher than 1.5 times normal) prevent participation.
  • Allergy or sensitivity to any study drug: A known reaction to any of the medicines being tested excludes the person.
  • Hereditary sugar metabolism problems: Individuals with inherited conditions such as fructose intolerance, or problems absorbing glucose, galactose, or sucrose‑isomaltose are not eligible.
  • Abnormal vital signs or heart test: Unusual blood pressure, heart rate, or an abnormal electrocardiogram (ECG) results lead to exclusion.
  • Mouth or throat wounds: Any sores, ulcers, or injuries in the mouth or throat at any time during the study disqualify the volunteer.
  • Current orthodontic treatment: People wearing braces or undergoing other dental alignment procedures cannot take part.
  • Recent use of other medicines: Taking any systemic or topical medication—including multivitamins, mineral supplements, or herbal products—within 7 days before screening (except up to 1 g per day of paracetamol) excludes a participant. Women must use contraceptives for at least 4 weeks before the study and keep the same method throughout.
  • Participation in another clinical trial: If the person has been in a study using experimental drugs within the past 3 months (or at least 1 month, whichever is longer, for studies with marketed drugs) they cannot join.
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Investigated drugs

  • Lidocaine Vitamin C GP

    is an oral lozenge that combines a mild local anesthetic (lidocaine) with vitamin C and two antiseptic ingredients (amylmetacresol and dichlorobenzyl alcohol). The lidocaine helps numb the throat to reduce pain, while the vitamin C and antiseptics work to soothe irritation and fight germs that can cause sore throats.

  • Strepsils con Vitamina C

    is an oral lozenge that contains vitamin C and the same two antiseptic ingredients (amylmetacresol and dichlorobenzyl alcohol) found in the test product, but it does not contain lidocaine. This lozenge is intended to relieve throat discomfort by providing vitamin C for immune support and antiseptics to reduce bacterial activity.

  • Strepsils con lidocaina

    is an oral lozenge that includes the local anesthetic lidocaine together with the antiseptic ingredients amylmetacresol and dichlorobenzyl alcohol, but it does not contain vitamin C. The lidocaine numbs the throat to lessen pain, while the antiseptics help control infection and irritation.

What is already known about the treatment

  • Lidocaine Vitamin C GP

    This lozenge is taken by mouth and dissolves slowly in the throat, delivering a mix of amylmetacresol, vitamin C (as ascorbic acid and sodium ascorbate), 2,4‑dichlorobenzyl alcohol, and lidocaine hydrochloride. It is an over‑the‑counter product that is widely available for treating sore throat symptoms. The lozenge works by using the antiseptic ingredients to reduce germs, the vitamin C to support local tissue health, and lidocaine to numb the throat by blocking pain signals. It is classified as an antiseptic, local anesthetic, and vitamin supplement combined in one lozenge.

  • Strepsils con Vitamina C pastillas para chupar

    This oral lozenge contains amylmetacresol, vitamin C (ascorbic acid and sodium ascorbate), and 2,4‑dichlorobenzyl alcohol and is dissolved slowly in the mouth. It is a commonly sold over‑the‑counter remedy for sore throat and mild cough. The antiseptic agents help lower the number of germs in the throat while the vitamin C may aid the body’s natural defenses. It is classified as an antiseptic‑vitamin C lozenge.

  • Strepsils con lidocaina pastillas para chupar

    This throat lozenge is taken orally and releases amylmetacresol, 2,4‑dichlorobenzyl alcohol, and lidocaine hydrochloride as it dissolves. It is an approved over‑the‑counter product used to ease throat pain. The antiseptic components act against microbes, and lidocaine provides pain relief by temporarily blocking the nerves that send pain signals. It is classified as an antiseptic and local anesthetic lozenge.

Investigated diseases

Healthy volunteer - Individuals without known disease who take part in the study. They remain symptom‑free and do not experience disease progression.
Trial detailsLast updated 21 Oct 2026
Age18+ yearsPhasePhase ITrial ID2023-507599-34-00Protocol codeG23-00Estimated enrolment60 patientsSponsorGeiser Pharma S.L.

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