HealhtyPhase 1NCT07442591
A Study to Assess Effect of Dosing Intervals on Multiple-Dose Pharmacokinetics of WD-1603 Taken Before Meals in Healthy Participants
A Phase 1 study of Healhty, run by Shanghai WD Pharmaceutical Co., Ltd. at 1 site in China.
Trial summary
WD-1603 contains two different drugs called levodopa and carbidopa in one tablet. The goal of this clinical trial is to see if taking the study drug WD-1603 at different time intervals affects how the drug acts in healthy volunteers. We also want to learn about the safety of WD-1603. Read more about this study
- Who is it for?
- Ages 18 to 55 yearsHealthy volunteers can take part
- Conditions the study is for
- Healhty
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 12 participants
- Where
- 1 siteChina
- Study dates
- 17 Mar 2026to 23 Apr 2026
- Phase
- Phase 1
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 55 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy adult male or female participants aged 18 to 55 years (inclusive) at the time of signing the informed consent form (ICF).
- Body weight: male ≥ 50 kg, female ≥ 45 kg; body mass index (BMI) between 18 and 27 kg/m² (inclusive) (BMI = weight [kg] / height² [m²]).
- Medical history inquiry, physical examination, vital signs, laboratory tests (complete blood count, urinalysis, blood biochemistry, serological virology tests, coagulation function), 12-lead ECG, intraocular pressure measurement, abdominal ultrasound, and chest X-ray during the screening period are all within normal ranges or clinically insignificant if outside normal ranges.
- Participants (including their spouses or partners) have no plans for conception or for donating sperm/eggs from the time of signing the ICF (for females)/first dosing (for males) until 3 months after the last dose, and voluntarily agree to use effective non-pharmacological contraception during the trial period.
- Fully understand the trial content, procedures, and potential adverse reactions, voluntarily agree to participate, and sign the ICF before any trial-related procedures begin.
- Able to communicate well with the investigators and capable of understanding and complying with the requirements of this trial.
Who cannot join
- Allergy-prone constitution, history of allergic diseases, or known severe allergic reaction or allergy history to levodopa/carbidopa or related medications.
- Drug use within 3 months prior to screening, history of drug abuse, or positive urine drug abuse screening (morphine, methamphetamine, ketamine, methylenedioxymethamphetamine, tetrahydrocannabinol acid, cocaine).
- History of glaucoma, cancer, diabetes mellitus, bronchial asthma, or any clinically significant cardiovascular, respiratory, metabolic, renal, hepatic, gastrointestinal, hematological, dermatological, endocrine, neuropsychiatric diseases, or other significant conditions.
- Dysphagia or any condition that may affect drug absorption (e.g., gastrectomy, cholecystectomy, gastric bypass, duodenotomy, colectomy), or gastrointestinal diseases causing clinically significant symptoms such as nausea, vomiting, diarrhea, or malabsorption syndrome.
- History of orthostatic hypotension.
- Any relevant medical history, surgical history, or trauma within 3 months prior to the first dose that may affect trial safety or drug pharmacokinetics, or planned surgery during the trial period.
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- Use of prescription drugs, over-the-counter medications, health products, Chinese herbal medicines, or dietary supplements within 4 weeks prior to the first dose, especially monoamine oxidase inhibitors (e.g., phenelzine, rasagiline, selegiline, brofaromine, toloxatone, isocarboxazid, etc.).
- Participation in any clinical trial and receipt of investigational drugs within 3 months prior to the first dose.
- Blood donation (including component blood) or significant blood loss (≥400 mL), blood transfusion, or use of blood products within 3 months prior to the first dose.
- Difficulty with venous access, unsuitability or unwillingness to use intravenous catheters, or history of needle/blood phobia.
- Heavy smokers or average daily cigarette consumption of more than 10 cigarettes within 3 months prior to screening.
- Alcohol consumption exceeding 21 standard units per week within 3 months prior to screening (1 standard unit contains 14g of alcohol, e.g., 360 mL of beer, 45 mL of 40% spirits, or 150 mL of wine), positive alcohol breath test, or unwillingness to abstain from alcohol from 48 hours before the first dose of each period until the completion of blood sampling for that period.
- Estimated glomerular filtration rate (eGFR) < 90 mL/min·1.73m² during the screening period.
- During screening: systolic blood pressure < 90 mmHg or ≥ 140 mmHg, diastolic blood pressure < 60 mmHg or ≥ 90 mmHg, pulse rate > 100 beats/min or < 50 beats/min.
- History of prolonged QT interval or other clinically significant cardiac diseases, or QTcF ≥ 450 ms on ECG during screening.
- Symptoms of acute infection (e.g., influenza) or acute gastroenteritis within 2 weeks prior to screening, or history of vomiting or diarrhea within 1 week prior to screening.
- Positive for hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (HCV-Ab), human immunodeficiency virus antibody (HIV-Ab), or Treponema pallidum antibody.
- Currently pregnant (including positive pregnancy test) or lactating female.
- Poor compliance as judged by the investigator, or other factors deemed unsuitable for participation in this trial.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: A Clinical Study to Assess the Effect of Different Dosing Intervals on the Multiple-Dose Pharmacokinetics of WD-1603 (25mg Carbidopa/150mg Levodopa) When Administered Before Meals in Healthy Participants
WD-1603 contains two different drugs called levodopa and carbidopa in one tablet. The goal of this clinical trial is to see if taking the study drug WD-1603 at different time intervals affects how the drug acts in healthy volunteers. We also want to learn about the safety of WD-1603.
The main question we want to answer is:
- How does the body process WD-1603 when it is taken by different time intervals? What will participants do?
- Participants will take one tablet of WD-1603 twice a day on three separate days.
- On each dosing day, the two doses will be spaced different hours apart.
- Between each dosing day, there will be a rest period of up to 7 days.
Read the detailed description
This trial is a multiple-dose, open-label, sequential, three-period pharmacokinetic study comparing different dosing intervals of WD-1603 in healthy participants.
The purpose of the study is:
- To evaluate the effect of different dosing intervals on the pharmacokinetics of twice-daily WD-1603 when administered before meals.
- To assess the safety and tolerability of WD-1603 in healthy participants. Each participant will receive the investigational drug in the sequence of Treatment A, Treatment B, and Treatment C. After each dosing period, there will be a washout period of up to 7 days.
This Phase I clinical trial is planned to enroll 12 healthy participants, with an appropriate proportion of female participants (at least one quarter, i.e., 3 participants).
Pharmacokinetic parameters will be calculated using Phoenix WinNonlin (version 8.3 or higher), and other analyses will be performed using SAS software (version 9.4 or higher). Using PKS, an analysis of variance (ANOVA) is performed on the natural log-transformed Cmax, AUC0-τ, and ΔC0.5. The model includes dosing occasion as a fixed effect and participant as a random effect. The 90% confidence interval for the geometric mean ratio (second dose/first dose) of each parameter is calculated.
- Conditions
- Healhty
- Being tested
- Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg)
- Keywords
- multiple-dose, open-label, pharmacokinetic
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg)Drug
Administered twice daily for one day with a 5-hour interval between doses.
Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg)Drug
Administered twice daily for one day with a 6-hour interval between doses.
Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg)Drug
Administered twice daily for one day with a 7-hour interval between doses.
| Study group | Role | What they receive |
|---|---|---|
| WD-1603 (25 mg/150 mg) 5-hour interval | Experimental | Cohort 1: Participants will take one WD-1603 25 mg/150 mg tablet orally 5 minutes before each meal, twice daily with a 5-hour interval between doses, over a 1-day dosing period. Receives: Drug: Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg) |
| WD-1603 (25 mg/150 mg) 6-hour interval | Experimental | Cohort 2: Participants will take one WD-1603 25 mg/150 mg tablet orally 5 minutes before each meal, twice daily with a 6-hour interval between doses, over a 1-day dosing period. Receives: Drug: Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg) |
| WD-1603 (25 mg/150 mg) 7-hour interval | Experimental | Cohort 3: Participants will take one WD-1603 25 mg/150 mg tablet orally 5 minutes before each meal, twice daily with a 7-hour interval between doses, over a 1-day dosing period. Receives: Drug: Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Maximal Plasma Concentration (Cmax) of Carbidopa and Levodopa
Maximal plasma concentration (Cmax) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Measured: 24 hours after the first dose.
Area under the Concentration versus Time Curve from 0 to Time t (AUC0-t) of Carbidopa and Levodopa
Area under the concentration versus time curve from 0 to time t (AUC0-t) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Measured: 24 hours after the first dose.
Area under the Concentration versus Time Curve from 0 Extrapolated to Infinity (AUC0-∞) of Carbidopa and Levodopa
Area under the concentration versus time curve from 0 extrapolated to infinity (AUC0-∞) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Measured: 24 hours after the first dose.
Time to Maximal Plasma Concentration (tmax) of Carbidopa and Levodopa
Time to maximal plasma concentration (tmax) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Measured: 24 hours after the first dose.
Elimination Half-life (t1/2) of Carbidopa and Levodopa
Elimination half-life (t1/2) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Measured: 24 hours after the first dose.
Terminal Elimination Rate Constant (λz) of Carbidopa and Levodopa
Terminal elimination rate constant (λz) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Measured: 24 hours after the first dose.
Apparent Clearance (CL/F) of Carbidopa and Levodopa
Apparent clearance (CL/F) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Measured: 24 hours after the first dose.
Apparent Volume of Distribution (Vd/F) of Carbidopa and Levodopa
Apparent volume of distribution (Vd/F) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Measured: 24 hours after the first dose.
Cmax of Levodopa and Carbidopa for Each Dose
Cmax of carbidopa and levodopa for each dose after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Measured: 24 hours after the first dose.
AUC0-τ of Levodopa and Carbidopa for Each Dose
AUC0-τ of carbidopa and levodopa for each dose after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants, where τ is the dosing interval.
Measured: 24 hours after the first dose.
Ratio of ΔC0.5 between the Two Doses
Ratio of ΔC0.5 of carbidopa and levodopa between the two doses after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants, where the ΔC0.5 of the first dose is equal to the concetration at 0.5 hour C0.5; the ΔC0.5 of the second dose is the difference between the concontration at t+0.5 hours (Ct+0.5) and the concentration at t (Ct) (t is the dosing interval).
Measured: 24 hours after the first dose.
Secondary outcomes (2)
Number and Percentage of Participants for Each Type of Adverse Events (AEs)
All AEs will be coded using MedDRA version 28.1 or higher to provide the System Organ Class (SOC) and Primary Term (PT) for each event. AEs will be summarized by treatment period, including the number and percentage of participants for each event category and for treatment-related adverse events. Additionally, summarize treatment-emergent adverse events (TEAEs) by treatment period for deaths, serious adverse events (SAEs), events leading to discontinuation of study medication, and events leading to early termination of the study.
Measured: Throughout the study, about 21 days.
Number and Percentage of Participants with Abnormal Findings in Laboratory Tests, Physical Examinations, Vital Signs and 12-lead Electrocardiogram (12-lead ECG)
Summarize measurements recorded at each time point (screening, baseline, each visit, and study completion) along with changes from baseline at each visit and study completion. Use cross-tabulation to summarize baseline values for each indicator and the most clinically significant change determined post-treatment.
Measured: Baseline, 1 week, 2 weeks and 3 weeks.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Mar 2026
- Study start17 Mar 2026
- Primary completion23 Apr 2026
- Study completion23 Apr 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (5)Papers the sponsor has linked to this study.
- Other trials for HealhtyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 1
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 12 participants (actual)
Sponsor and investigators
- Lead sponsor
- Shanghai WD Pharmaceutical Co., Ltd.
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- Xuhui Central Hospital, Shanghai, BalGenSource Medical Technology Co. Ltd., Shanghai Xihua Scientific Co., Ltd., Shanghai BioGuider Medical Technology Co., Ltd.
- Responsible party
- Sponsor
- Investigators
- Yanmei Liu, Master, Principal investigator, Xuhui Central Hospital, Shanghai
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07442591
- Sponsor's protocol ID
- WD-1603-1010
- Other IDs
- CTR20260505
- Status last verified
- Sep 2026
- First submitted
- 12 Feb 2026
- Last updated
- 23 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
中华医学会神经病学分会帕金森病及运动障碍学组 and 中国医师协会神经内科医师分会帕金森病及运动障碍学组, 中国帕金森病治疗指南（第四版）. 中华神经科杂志, 2020. 53(12): p. 973-986.
Kempster PA, Frankel JP, Bovingdon M, Webster R, Lees AJ, Stern GM. Levodopa peripheral pharmacokinetics and duration of motor response in Parkinson's disease. J Neurol Neurosurg Psychiatry. 1989 Jun;52(6):718-23. doi: 10.1136/jnnp.52.6.718.
PubMed 2501456Adepu S, Ramakrishna S. Controlled Drug Delivery Systems: Current Status and Future Directions. Molecules. 2021 Sep 29;26(19):5905. doi: 10.3390/molecules26195905.
PubMed 34641447Buril J, Burilova P, Pokorna A, Kovacova I, Balaz M. Representation of Parkinson's disease and atypical Parkinson's syndromes in the Czech Republic-A nationwide retrospective study. PLoS One. 2021 Feb 2;16(2):e0246342. doi: 10.1371/journal.pone.0246342. eCollection 2021.
PubMed 33529251Tysnes OB, Storstein A. Epidemiology of Parkinson's disease. J Neural Transm (Vienna). 2017 Aug;124(8):901-905. doi: 10.1007/s00702-017-1686-y. Epub 2017 Feb 1.
PubMed 28150045
Study at a glance
From the registry record, last updated by the sponsor on 23 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Clinical Study to Assess the Effect of Different Dosing Intervals on the Multiple-Dose Pharmacokinetics of WD-1603 (25mg Carbidopa/150mg Levodopa) When Administered Before Meals in Healthy Participants
- ClinicalTrials.gov ID
- NCT07442591
- Acronym / sponsor ID
- WD-1603-1010
- Conditions
- Healhty
- Keywords
- multiple-dose, open-label, pharmacokinetic
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 12 participants (actual)
- Lead sponsor
- Shanghai WD Pharmaceutical Co., Ltd.Industry (pharma, biotech, devices)
- Collaborators
- Xuhui Central Hospital, Shanghai, BalGenSource Medical Technology Co. Ltd., Shanghai Xihua Scientific Co., Ltd., Shanghai BioGuider Medical Technology Co., Ltd.
- Study start
- 17 Mar 2026 (actual)
- Primary completion
- 23 Apr 2026 (actual)
- Study completion
- 23 Apr 2026 (actual)
- First posted
- 2 Mar 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
WD-1603 contains two different drugs called levodopa and carbidopa in one tablet. The goal of this clinical trial is to see if taking the study drug WD-1603 at different time intervals affects how the drug acts in healthy volunteers. We also want to learn about the safety of WD-1603.
The main question we want to answer is:
- How does the body process WD-1603 when it is taken by different time intervals? What will participants do?
- Participants will take one tablet of WD-1603 twice a day on three separate days.
- On each dosing day, the two doses will be spaced different hours apart.
- Between each dosing day, there will be a rest period of up to 7 days.
Detailed description
This trial is a multiple-dose, open-label, sequential, three-period pharmacokinetic study comparing different dosing intervals of WD-1603 in healthy participants.
The purpose of the study is:
- To evaluate the effect of different dosing intervals on the pharmacokinetics of twice-daily WD-1603 when administered before meals.
- To assess the safety and tolerability of WD-1603 in healthy participants. Each participant will receive the investigational drug in the sequence of Treatment A, Treatment B, and Treatment C. After each dosing period, there will be a washout period of up to 7 days.
This Phase I clinical trial is planned to enroll 12 healthy participants, with an appropriate proportion of female participants (at least one quarter, i.e., 3 participants).
Pharmacokinetic parameters will be calculated using Phoenix WinNonlin (version 8.3 or higher), and other analyses will be performed using SAS software (version 9.4 or higher). Using PKS, an analysis of variance (ANOVA) is performed on the natural log-transformed Cmax, AUC0-τ, and ΔC0.5. The model includes dosing occasion as a fixed effect and participant as a random effect. The 90% confidence interval for the geometric mean ratio (second dose/first dose) of each parameter is calculated.
Study design
- Primary purpose
- Treatment
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| WD-1603 (25 mg/150 mg) 5-hour interval | Experimental | Drug: Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg)Cohort 1: Participants will take one WD-1603 25 mg/150 mg tablet orally 5 minutes before each meal, twice daily with a 5-hour interval between doses, over a 1-day dosing period. |
| WD-1603 (25 mg/150 mg) 6-hour interval | Experimental | Drug: Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg)Cohort 2: Participants will take one WD-1603 25 mg/150 mg tablet orally 5 minutes before each meal, twice daily with a 6-hour interval between doses, over a 1-day dosing period. |
| WD-1603 (25 mg/150 mg) 7-hour interval | Experimental | Drug: Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg)Cohort 3: Participants will take one WD-1603 25 mg/150 mg tablet orally 5 minutes before each meal, twice daily with a 7-hour interval between doses, over a 1-day dosing period. |
Who may qualify
- Ages
- 18 to 55 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (6 listed)
- Healthy adult male or female participants aged 18 to 55 years (inclusive) at the time of signing the informed consent form (ICF).
- Body weight: male ≥ 50 kg, female ≥ 45 kg; body mass index (BMI) between 18 and 27 kg/m² (inclusive) (BMI = weight [kg] / height² [m²]).
- Medical history inquiry, physical examination, vital signs, laboratory tests (complete blood count, urinalysis, blood biochemistry, serological virology tests, coagulation function), 12-lead ECG, intraocular pressure measurement, abdominal ultrasound, and chest X-ray during the screening period are all within normal ranges or clinically insignificant if outside normal ranges.
- Participants (including their spouses or partners) have no plans for conception or for donating sperm/eggs from the time of signing the ICF (for females)/first dosing (for males) until 3 months after the last dose, and voluntarily agree to use effective non-pharmacological contraception during the trial period.
- Fully understand the trial content, procedures, and potential adverse reactions, voluntarily agree to participate, and sign the ICF before any trial-related procedures begin.
Key exclusion criteria (19 listed)
- Allergy-prone constitution, history of allergic diseases, or known severe allergic reaction or allergy history to levodopa/carbidopa or related medications.
- Drug use within 3 months prior to screening, history of drug abuse, or positive urine drug abuse screening (morphine, methamphetamine, ketamine, methylenedioxymethamphetamine, tetrahydrocannabinol acid, cocaine).
- History of glaucoma, cancer, diabetes mellitus, bronchial asthma, or any clinically significant cardiovascular, respiratory, metabolic, renal, hepatic, gastrointestinal, hematological, dermatological, endocrine, neuropsychiatric diseases, or other significant conditions.
- Dysphagia or any condition that may affect drug absorption (e.g., gastrectomy, cholecystectomy, gastric bypass, duodenotomy, colectomy), or gastrointestinal diseases causing clinically significant symptoms such as nausea, vomiting, diarrhea, or malabsorption syndrome.
- History of orthostatic hypotension.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg)Administered twice daily for one day with a 5-hour interval between doses. | Drug | WD-1603 (25 mg/150 mg) 5-hour interval |
| Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg)Administered twice daily for one day with a 6-hour interval between doses. | Drug | WD-1603 (25 mg/150 mg) 6-hour interval |
| Carbidopa and Levodopa Controlled-Release Tablets (25 mg/150 mg)Administered twice daily for one day with a 7-hour interval between doses. | Drug | WD-1603 (25 mg/150 mg) 7-hour interval |
Primary outcome
Maximal Plasma Concentration (Cmax) of Carbidopa and Levodopa
Time frame: 24 hours after the first dose.
Maximal plasma concentration (Cmax) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Area under the Concentration versus Time Curve from 0 to Time t (AUC0-t) of Carbidopa and Levodopa
Time frame: 24 hours after the first dose.
Area under the concentration versus time curve from 0 to time t (AUC0-t) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Area under the Concentration versus Time Curve from 0 Extrapolated to Infinity (AUC0-∞) of Carbidopa and Levodopa
Time frame: 24 hours after the first dose.
Area under the concentration versus time curve from 0 extrapolated to infinity (AUC0-∞) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Time to Maximal Plasma Concentration (tmax) of Carbidopa and Levodopa
Time frame: 24 hours after the first dose.
Time to maximal plasma concentration (tmax) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Elimination Half-life (t1/2) of Carbidopa and Levodopa
Time frame: 24 hours after the first dose.
Elimination half-life (t1/2) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Terminal Elimination Rate Constant (λz) of Carbidopa and Levodopa
Time frame: 24 hours after the first dose.
Terminal elimination rate constant (λz) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Apparent Clearance (CL/F) of Carbidopa and Levodopa
Time frame: 24 hours after the first dose.
Apparent clearance (CL/F) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Apparent Volume of Distribution (Vd/F) of Carbidopa and Levodopa
Time frame: 24 hours after the first dose.
Apparent volume of distribution (Vd/F) of carbidopa and levodopa after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
Cmax of Levodopa and Carbidopa for Each Dose
Time frame: 24 hours after the first dose.
Cmax of carbidopa and levodopa for each dose after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants.
AUC0-τ of Levodopa and Carbidopa for Each Dose
Time frame: 24 hours after the first dose.
AUC0-τ of carbidopa and levodopa for each dose after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants, where τ is the dosing interval.
Ratio of ΔC0.5 between the Two Doses
Time frame: 24 hours after the first dose.
Ratio of ΔC0.5 of carbidopa and levodopa between the two doses after two doses of WD-1603 administered orally before meals at different dosing intervals in healthy participants, where the ΔC0.5 of the first dose is equal to the concetration at 0.5 hour C0.5; the ΔC0.5 of the second dose is the difference between the concontration at t+0.5 hours (Ct+0.5) and the concentration at t (Ct) (t is the dosing interval).
2 secondary outcomes
Number and Percentage of Participants for Each Type of Adverse Events (AEs)
Time frame: Throughout the study, about 21 days.
Number and Percentage of Participants with Abnormal Findings in Laboratory Tests, Physical Examinations, Vital Signs and 12-lead Electrocardiogram (12-lead ECG)
Time frame: Baseline, 1 week, 2 weeks and 3 weeks.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Sep 2026.
- Background中华医学会神经病学分会帕金森病及运动障碍学组 and 中国医师协会神经内科医师分会帕金森病及运动障碍学组, 中国帕金森病治疗指南（第四版）. 中华神经科杂志, 2020. 53(12): p. 973-986.
- Background: PubMed 2501456Kempster PA, Frankel JP, Bovingdon M, Webster R, Lees AJ, Stern GM. Levodopa peripheral pharmacokinetics and duration of motor response in Parkinson's disease. J Neurol Neurosurg Psychiatry. 1989 Jun;52(6):718-23. doi: 10.1136/jnnp.52.6.718.
- Background: PubMed 34641447Adepu S, Ramakrishna S. Controlled Drug Delivery Systems: Current Status and Future Directions. Molecules. 2021 Sep 29;26(19):5905. doi: 10.3390/molecules26195905.
- Background: PubMed 33529251Buril J, Burilova P, Pokorna A, Kovacova I, Balaz M. Representation of Parkinson's disease and atypical Parkinson's syndromes in the Czech Republic-A nationwide retrospective study. PLoS One. 2021 Feb 2;16(2):e0246342. doi: 10.1371/journal.pone.0246342. eCollection 2021.
- Background: PubMed 28150045Tysnes OB, Storstein A. Epidemiology of Parkinson's disease. J Neural Transm (Vienna). 2017 Aug;124(8):901-905. doi: 10.1007/s00702-017-1686-y. Epub 2017 Feb 1.
- SINEMET CR \[package insert\].Link provided by the sponsor.
- Individual participant dataSharing planned: No
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Healhty
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Yanmei Liu, Master principal investigator
Xuhui Central Hospital, Shanghai
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study of Healhty, run by Shanghai WD Pharmaceutical Co., Ltd. at 1 site in China.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 19 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 23 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Maximal Plasma Concentration (Cmax) of Carbidopa and Levodopa (time frame: 24 hours after the first dose.). The study lists 11 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07442591, which also lists 5 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Sep 2026.