Study of Valacyclovir Oral Suspension Bioavailability Compared with Valaciclovir Hydrochloride Extemporaneous Suspension in Healthy Adults (fasted and fed conditions)

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What is this study about?

The study examines the medicine valacyclovir, which is available as the tablet brand Valtrex and as a liquid oral suspension. Both forms contain the same active ingredient and are taken by mouth.

The purpose is to compare the bioavailability of the liquid suspension with that of the tablet form and to see whether eating food changes how much of the drug reaches the bloodstream.

Healthy volunteers will receive each form of the medicine in separate periods, sometimes on an empty stomach and sometimes after a meal, using a crossover design. Blood samples will be collected to measure the drug levels over time, which is part of a pharmacokinetic assessment, and participants will be monitored for any side effects.

1 randomization and assignment to treatment sequence

after joining the study, a computer will assign you to one of three possible sequences. each sequence determines the order in which you will receive the two forms of valacyclovir (a tablet suspension and an oral suspension) and whether you will take them while fasting or after a meal.

2 first study period – fasting dose

you will be asked to avoid eating or drinking anything except water for at least ten hours before the visit.

on the day of the visit you will take a single dose of valacyclovir equal to 1 gram. the dose will be given either as a tablet that is crushed and mixed with water to form a suspension, or as a powder that you will mix with water to create an oral suspension, depending on your assigned sequence.

the dose is taken by mouth under the supervision of study staff.

3 blood sampling after the first dose

shortly after you take the medication, small amounts of blood will be drawn at several time points over the next several hours. these samples are used to measure how much valacyclovir and its breakdown product acyclovir are in your bloodstream.

4 washout period

after the first period you will wait for a washout period, typically about seven days, to allow the drug to leave your body completely before the next dose.

5 second study period – fed or fasting dose

depending on your sequence, the second period may require you to eat a standard high‑fat meal before taking the medication, or to remain fasting as described in step 2.

you will again receive a single 1‑gram dose of valacyclovir in the form assigned for this period (tablet suspension or oral suspension) and swallow it under observation.

6 blood sampling after the second dose

as in the first period, blood will be drawn at multiple time points after the dose to assess the drug’s appearance and clearance from your blood.

7 second washout period

you will again wait for a washout period of about seven days before the final period.

8 third study period – the remaining condition

in the last period you will receive the remaining form of valacyclovir (tablet suspension or oral suspension) and the opposite food condition from the second period (fasting if you previously ate, or fed if you previously fasted).

the dose remains 1 gram and is taken orally under supervision.

9 final blood sampling

blood samples will be collected at the same scheduled times as in the earlier periods to complete the pharmacokinetic assessment.

10 study completion

after the last blood draw the study procedures are finished. no further medication is taken.

Who Can Join the Study?

Be a healthy man or woman (not pregnant and not breastfeeding) who is between 18 and 45 years old.
Have a Body Mass Index (BMI) from 18.5 to 30 and weigh between 50 kg and 100 kg. (BMI is a simple calculation that relates weight to height.)
Be willing and able to follow the study visits and procedures, and sign a written informed consent form.
Have a blood pressure (the force of blood against artery walls) measured after sitting for 5 minutes that is between 90 and 140 mm Hg systolic (upper number) and no higher than 90 mm Hg diastolic (lower number), and a heart rate (beats per minute) between 50 and 90.
Be generally healthy as shown by medical history, a physical exam, and vital signs; small differences that the doctor says are not important are allowed.
Not have used any nicotine‑containing products (such as cigarettes, vaping, or chewing tobacco) in the 30 days before taking the study medication.
Show a negative result on a urine drug screen at the screening visit and again at the check‑in visit (this test checks for illegal or recreational drugs).
Show a negative result on an alcohol breath test at the screening visit and again at the check‑in visit (this test checks for recent alcohol use).
Show a negative result on a urine cotinine test at the screening visit and again at the check‑in visit (cotinine is a substance that indicates recent nicotine use).
Have all laboratory test results within normal limits, unless the investigator decides that any small deviation is not clinically important.
If female, be either postmenopausal (no natural periods for at least one year), surgically sterile, abstinent, or using an effective method of birth control throughout the study.
If female, have a negative pregnancy test (blood β‑hCG at screening and urine at check‑in).
If male, agree to use appropriate contraception, not donate sperm during the study and for three months after the last dose.
Be able to understand and speak Czech fluently.

Who Cannot Join the Study?

No prescription or over‑the‑counter medicines (including vitamins, food supplements, and herbal products) taken within 28 days before the first dose, except oral contraceptives or hormone therapy that have been stable for 90 days. (Prescription medication requires a doctor’s order; OTC medication can be bought without a prescription.)
No use of drugs that are toxic to organs or that strongly affect liver enzymes, especially those that change the activity of a liver enzyme called CYP1A2, within 90 days before the first dose.
Not have taken part in another clinical study or used any investigational drug or device within 30 days (or at least five drug half‑lives, whichever is longer) before screening. (Half‑life is the time it takes for half of a drug to leave the body.)
No serious mental illness and must be able to cooperate with the study team.
No blood, stomach‑gut, heart, kidney, or liver diseases (or past history of them) that could affect how the drug works.
No current or past diabetes, thyroid problems, nerve disease, infections, or any other illness the doctor thinks could interfere with the study.
No acute (sudden) or chronic (long‑lasting) disease or health findings that could interfere with the study’s goals or the safety of the drug.
No current or past irregular heart rhythm, other heart disease, blood disorders, clotting problems, abnormal cholesterol, or lung disease that the doctor feels should exclude you.
No severe liver damage, defined as liver enzymes ALT or AST at least twice the normal upper limit (ULN). (ALT and AST are chemicals measured to check liver health.)
No significant illness within 28 days before the first dose, including major surgery.
No abnormal blood test, chemistry, or urine test results that the doctor considers important.
Not test positive for HIV, hepatitis B surface antigen (HBsAg), or hepatitis C at screening.
No important abnormal findings on physical exam, vital signs, or a 12‑lead ECG (heart tracing) at screening, unless the doctor decides they are not significant.
Body temperature must be between 35.4 °C and 37.0 °C (95.7 °F‑98.6 °F) at screening and check‑in; temperatures outside this range exclude you.
No new tattoo, body piercing, or skin‑penetrating cosmetic procedure within 90 days before screening unless the doctor decides it is not a problem.
No donation of at least 500 mL of blood within 90 days, or donation of plasma or platelets within 14 days before the first dose.
No anemia, defined as hemoglobin below 120 g/L for women or 130 g/L for men at screening. (Hemoglobin is a protein in red blood cells that carries oxygen.)
Veins in the arms must be suitable for blood collection; if they are not, you cannot participate.
No use of recreational drugs and no history of drug abuse or alcoholism.
No antiviral medication (including creams or eye drops) within 14 days (or 10 drug half‑lives, whichever is longer) before the first dose.
No current kidney problems, defined as creatinine clearance less than 50 mL/min/1.73 m² at screening. (Creatinine clearance measures how well the kidneys filter waste.)
No severe allergy to acyclovir, valacyclovir, their related drugs, heparin, or any of the ingredients (excipients) in the study medicine.
Exclusion related to COVID‑19 as defined in the study protocol.
Any other condition or abnormal finding that the doctor thinks would increase risk or make it hard to obtain reliable study data.

Where you can join this trial?

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Site Name	City	Country	Status
Qtctktszglmirljk svvesu	Prague	Czechia

Trial status

Country	Status	Recruitment Start
Czechia	Not recruiting	20.09.2023

Trial locations

Investigated Drugs:

VALACICLOVIR HYDROCHLORIDE

VALTREX is a brand-name tablet that contains the antiviral medicine valaciclovir. In this study, the tablets were crushed and mixed with water to create a liquid (extemporaneous suspension) so it can be compared with the new liquid form. It serves as the standard or “comparator” to show how the usual tablet version behaves in the body when given as a suspension.

Valacyclovir Oral Suspension is a powder that is mixed with water to make a liquid medication containing the same antiviral ingredient, valaciclovir. This new liquid form is the “test” product being evaluated. The study looks at how well the body absorbs this suspension compared to the standard tablet suspension and also examines whether eating food changes its absorption.

Herpes simplex virus infection – A viral infection that causes painful blisters on the skin or mucous membranes, which may recur when the virus reactivates and spreads to nearby areas. Herpes zoster – A reactivation of varicella‑zoster virus that produces a painful, localized rash following a nerve pathway, with skin lesions that gradually crust over and heal over several weeks.

Trial ID:

2023-504760-42-00

Trial Phase:

Human Pharmacology (Phase I) – Bioequivalence Study

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Study of Valacyclovir Oral Suspension Bioavailability Compared with Valaciclovir Hydrochloride Extemporaneous Suspension in Healthy Adults (fasted and fed conditions)

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?