Comparative Bioavailability Study of Carbidopa/Levodopa Extended-Release Tablets Under Fasting and Fed Conditions

August 24, 2026 updated by: Shanghai WD Pharmaceutical Co., Ltd.

An Open-label, Balanced, Randomized, Five-treatment, Five-period, Five-sequence, Multiple Oral Dose, Crossover Comparative Bioavailability Study of Different Strengths of Carbidopa/Levodopa Extended-release Tablets With Carbidopa and Levodopa Tablets in Normal, Healthy Adult Human Subjects Under Fasting and Fed Conditions

It is an open-label, balanced, randomized, five-treatment, five-period, five-sequence, multiple oral dose, crossover comparative bioavailability study of different strengths of carbidopa/levodopa extended-release tablets with carbidopa and levodopa tablets in normal, healthy adult human subjects under fasting and fed conditions. The primary objective of the study is to compare the pharmacokinetic profiles between WD-1603 extended-release formulations and carbidopa and levodopa tablets 25mg/100mg following three times a day after oral administration in fasting and fed conditions in healthy subjects and to compare relative bioavailability between treatments.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Study WD-1603-1005 is to compare the fluctuation index between WD-1603 extended-release formulations and Carbidopa and Levodopa Tablets following three times a day oral administration and the food effect on the initial absorption of levodopa in the morning in healthy subjects. At least 15 subjects will be enrolled at the beginning of the study and the order of receiving the Treatment A, B, C, D & E for each subject during all the periods of the the study will be determined according to a randomization schedule.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
15

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • India
    • Gujarat
      • Ahmedabad, Gujarat, India, 382481
        • Lambda Therapeutic Research Ltd.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 45 years (Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Normal, healthy adult human volunteers between 18 to 45 years of age (both inclusive).
  2. Having a Body Mass Index (BMI) between 18.5 to 29.9 (both inclusive), calculated as weight in kg/ height in m2, a minimum body weight of 50.0 kg.
  3. Not having any significant disease or clinically significant abnormal findings during screening, medical history, clinical examination, laboratory evaluations, 12- lead ECG, and X-ray chest (P/A view) recordings.
  4. In the case of female subjects:

a. Surgically sterilized at least 6 months prior to study participation or If of childbearing potential is willing to use a suitable and effective double barrier contraceptive method or intra-uterine device during the study and for at least 28 days after the last study drug administration.

And b. Serum Pregnancy test must be negative.

Exclusion Criteria:

  1. Known hypersensitivity or idiosyncratic reaction to Carbidopa or Levodopa or any of the excipients or any related drug.
  2. History or presence of any disease or condition which might compromise the hemopoietic, renal, hepatic, endocrine, pulmonary, central nervous, cardiovascular, immunological, dermatological, gastrointestinal, or any other body system.
  3. Ingestion of a medicine (prescribed & over the counter (OTC) medication including herbal remedies and MAO inhibitors) at any time within 30 days before first dosing in Period I. In any such case, subject selection will be at the discretion of the Principal Investigator.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: 25 mg /100 mg treatment A group
Treatment A: carbidopa/levodopa (25 mg /100 mg)
Drug: WD-1603 Carbidopa-Levodopa Extended-Release Tablets
For fasting conditions in the morning, a single oral dose will be administered to each subject under fasting conditions before 5 minutes of serving a standardized vegetarian breakfast as per the randomization schedule; for fasting conditions in the afternoon and evening, a single oral dose will be administered to each subject under fasting condition before 5 minutes of serving standardized vegetarian lunch and dinner as per randomization schedule. For fed condition, single oral dose will be administered to each subject after 30 minutes of serving standardized vegetarian breakfast, lunch and dinner as per randomization schedule. Dosing interval between two subsequent dosing should be 5 hours in each period. There will be one tablet for A, B, C, D and E.
Other Names:
  • WD-1603
Experimental: 25 mg /150 mg treatment B group
Treatment B: carbidopa/levodopa (25 mg/150mg)
Drug: WD-1603 Carbidopa-Levodopa Extended-Release Tablets
For fasting conditions in the morning, a single oral dose will be administered to each subject under fasting conditions before 5 minutes of serving a standardized vegetarian breakfast as per the randomization schedule; for fasting conditions in the afternoon and evening, a single oral dose will be administered to each subject under fasting condition before 5 minutes of serving standardized vegetarian lunch and dinner as per randomization schedule. For fed condition, single oral dose will be administered to each subject after 30 minutes of serving standardized vegetarian breakfast, lunch and dinner as per randomization schedule. Dosing interval between two subsequent dosing should be 5 hours in each period. There will be one tablet for A, B, C, D and E.
Other Names:
  • WD-1603
Experimental: 25 mg /150 mg treatment C group
Treatment C: carbidopa/levodopa (25 mg /150 mg)
Drug: WD-1603 Carbidopa-Levodopa Extended-Release Tablets
For fasting conditions in the morning, a single oral dose will be administered to each subject under fasting conditions before 5 minutes of serving a standardized vegetarian breakfast as per the randomization schedule; for fasting conditions in the afternoon and evening, a single oral dose will be administered to each subject under fasting condition before 5 minutes of serving standardized vegetarian lunch and dinner as per randomization schedule. For fed condition, single oral dose will be administered to each subject after 30 minutes of serving standardized vegetarian breakfast, lunch and dinner as per randomization schedule. Dosing interval between two subsequent dosing should be 5 hours in each period. There will be one tablet for A, B, C, D and E.
Other Names:
  • WD-1603
Experimental: 25 mg /150 mg treatment D group
Treatment D: carbidopa/levodopa (25 mg /150 mg)
Drug: WD-1603 Carbidopa-Levodopa Extended-Release Tablets
For fasting conditions in the morning, a single oral dose will be administered to each subject under fasting conditions before 5 minutes of serving a standardized vegetarian breakfast as per the randomization schedule; for fasting conditions in the afternoon and evening, a single oral dose will be administered to each subject under fasting condition before 5 minutes of serving standardized vegetarian lunch and dinner as per randomization schedule. For fed condition, single oral dose will be administered to each subject after 30 minutes of serving standardized vegetarian breakfast, lunch and dinner as per randomization schedule. Dosing interval between two subsequent dosing should be 5 hours in each period. There will be one tablet for A, B, C, D and E.
Other Names:
  • WD-1603
Placebo Comparator: 25 mg /100 mg placebo group
Treatment E(Reference): Carbidopa and Levodopa tablets (a generic version of Sinemet® IR) 25 mg/100 mg
Drug: WD-1603 Carbidopa-Levodopa Extended-Release Tablets
For fasting conditions in the morning, a single oral dose will be administered to each subject under fasting conditions before 5 minutes of serving a standardized vegetarian breakfast as per the randomization schedule; for fasting conditions in the afternoon and evening, a single oral dose will be administered to each subject under fasting condition before 5 minutes of serving standardized vegetarian lunch and dinner as per randomization schedule. For fed condition, single oral dose will be administered to each subject after 30 minutes of serving standardized vegetarian breakfast, lunch and dinner as per randomization schedule. Dosing interval between two subsequent dosing should be 5 hours in each period. There will be one tablet for A, B, C, D and E.
Other Names:
  • WD-1603

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Cmax of the pharmacokinetics of WD-1603 extended-release formulations and carbidopa and levodopa tablets 25mg/100mg from the morning of day 1 to the morning of day 2.
Time Frame: 24 hours-from morning of Day 1 to morning of Day 2
To evaluate Cmax (Maximum Plasma Concentration) of the pharmacokinetics of WD-1603 extended-release formulations and carbidopa and levodopa tablets 25mg/100mg following three times a day after oral administration in fasting and fed conditions in healthy subjects.
24 hours-from morning of Day 1 to morning of Day 2
The duration (hours) for the levodopa concentrations ≥ 50% of Cmax between WD-1603 extended-release formulations and carbidopa and levodopa tablets following three times a day orally administration in healthy subjects.
Time Frame: 24 hours-from morning of Day 1 to morning of Day 2
To compare the duration (hours) for the levodopa concentrations ≥ 50% of Cmax, where maximum measured plasma concentration after 1st dose or 2nd or 3rd dose for each dose interval.
24 hours-from morning of Day 1 to morning of Day 2

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Shanghai WD Pharmaceutical Co., Ltd.

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Akash Patel, M.D., Lambda Therapeutic Research Ltd.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 29, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 9, 2021

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 9, 2021

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 27, 2021

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 10, 2021

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 19, 2021

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
August 26, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 24, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • WD-1603-1005

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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