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Pharmacokinetic Study in Healthy VolunteersSOLA-1NCT07817030

Evaluation of Solanidine as an Exogenous Biomarker to Phenotype CYP2D6 Activity in Humans

A study testing Yohimbine and Consumption of a defined potato-rich meal in people with Pharmacokinetic Study in Healthy Volunteers, run by University Medicine Greifswald at 1 site in Germany.

Not yet recruiting

Opening soon. The study is approved but enrolment has not started yet. Sites may already take enquiries.

Sites and contacts
Official record
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Trial summary

This study investigates the evaluation of solanidine as an exogenous biomarker to phenotype CYP2D6-activity in humans. Participants will be classified by their CYP2D6 genotype into poor metabolizers (PM), low intermediate metabolizers (LIM), extensive metabolizers (EM) and ultra-rapid metabolizers (UM), forming four… Read more about this study

Who is it for?
Ages 18 to 40 yearsHealthy volunteers can take part
What is being tested?
Yohimbine and Consumption of a defined potato-rich meal
Type of treatment
Pill or oral medicine
Could I receive a placebo?
No, everyone receives an active treatment
How many people
30 participants
Where
1 siteGermany
Study dates
21 Sep 2026to 31 Dec 2027
Phase
Interventional
Are there results?
Not yet: the study is under way

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 40 years
  • All sexes
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • individuals of both biological sexes, assigned as women or men at birth
  • age: ≥ 18 and ≤ 40 years
  • possesses the ability to understand the study purpose and design
  • contractually capable and provides signed informed consent form
  • in good general health or with mild and/or well-managed conditions such as allergies, asthma, hypertension or orthopedic diseases
  • taking no more than three chronic medications
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  • ability to maintain and record a detailed dietary protocol focusing on the consumption of potato-based products for the specified duration of the study
  • individuals classified as either ultrarapid metabolizers (UM), extensive metabolizers (EM), low intermediate metabolizers (LIM) or poor metabolizers (PM) based on their CYP2D6 genotype:
  • Poor Metabolizer (PM, Gen-Score 0):
  • homozygous or compound heterozygous for CYP2D6 3, CYP2D6 4, CYP2D65, CYP2D6 6
  • Low Intermediate Metabolizer (LIM, Gen-Score 0,25 or 0,5):
  • Homozygous or compound heterozygous for CYP2D6 9, 10, 41 or compound heterozygous with one allele of CYP2D6 3, CYP2D6 4, CYP2D65, or CYP2D66 and one allele of CYP2D6 17 (0,5) or CYP2D6 9, 10, or 41 (0,25)
  • Extensive Metabolizer (EM, Gene-Score 2):
  • homozygous or compound heterozygous for CYP2D6 1, CYP2D6 2, CYP2D635
  • Ultrarapid Metabolizer (UM, Gen-Score ≥ 3):
  • homozygous or compound heterozygous for CYP2D6 1, CYP2D6 2, CYP2D635 with at least one allele duplicated or multiplied

Who cannot join

  • BMI > 30 kg/m2 and < 18 kg/m2
  • body weight < 48 kg
  • women: known pregnancy or lactation period; positive urine pregnancy test at screening or kinetic visit
  • men: hemoglobin < 13 g/dl (8,07 mmol/l) women: hemoglobin < 12 g/dl (7,45 mmol/l)
  • elevated liver function tests (1 or more of ALAT, ASAT, yGT, Bilirubin > 2x ULN)
  • reduced renal function (eGFRMDRD < 60 mL/min/1,7 m2)
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  • QTcF > 450 ms in screening ECG
  • current or recent psychiatric disorders requiring treatment including depression, bipolar disorder, schizophrenia, psychosis or severe anxiety disorders
  • drug dependency at the time of visit
  • use of recreational drugs more than twice a week
  • intake of drugs interfering with CYP2D6 during the past seven days
  • any known hypersensitivity or allergic reactions to yohimbine
  • intake of yohimbine within 48 hours prior to study participation
  • history of hypersensitivity or allergy to potatoes or nightshade vegetables
  • intake of potato-containing meals during the three days before and after eating the potato-rich test meal
  • history of severe hypersensitivity reactions and/or anaphylaxis
  • poor venous conditions that make it impossible to place a peripheral venous catheter and regularly draw blood through it
  • engagement in extreme physical activity within 48 hours prior to study participation

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Germany1 site
  • University Medicine Greifswald

    Greifswald, Mecklenburg-Vorpommern, 17489

    Stefan Engeli, Prof. Dr., +49 3834 86 5633, stefan.engeli@med.uni-greifswald.de

    Stefan Engeli, Prof. Dr.

Other trials in Germany

About this study

This study investigates the evaluation of solanidine as an exogenous biomarker to phenotype CYP2D6-activity in humans. Participants will be classified by their CYP2D6 genotype into poor metabolizers (PM), low intermediate metabolizers (LIM), extensive metabolizers (EM) and ultra-rapid metabolizers (UM), forming four distinct study arms:

Arm 1) Poor Metabolizers (PM) n=10 Arm 2) Low Intermediate Metabolizers (LIM) n=5 Arm 3) Extensive Metabolizers (EM) n=10 Arm 4) Ultra-rapid Metabolizers (UM) n=5

Read more

Participants will be given a standardized potato-rich meal, serving as the natural source of solanidine, and will be phenotyped for CYP2D6 activity with a single oral microdose of the probe drug yohimbine.

The objectives of the study are as follows:

  1. To evaluate the suitability of the SSDA/solanidine and m414/solanidine metabolic ratio as an exogenous biomarker to phenotype CYP2D6 activity in humans.
  2. To characterize the postprandial plasma concentration profile of solanidine, its CYP2D6-dependent metabolites, and its parent molecules α-solanine and α-chaconine following a potato-rich meal.
Read the detailed description

The study follows an open-label, controlled, parallel-cohort design with four study arms based on CYP2D6 genotype. The study consists of two parts: a Yohimbine and a Potato Part.

Yohimbine Part:

Participants will receive a single oral microdose of 50 μg of yohimbine, administered in a fasted state as 2 x 1 tablets of Yohimbinum hydrochloricum D4® (Deutsche Homöopathie Union, Karlsruhe, Germany, containing 25 μg per tablet). A total of 6 blood samples will be collected at defined time points (baseline; 10; 20; 30; 60; 120 min). At each time point, 5 mL of blood will be drawn for plasma separation to determine yohimbine and the primary metabolite 11-OH-yohimbine. The blood sampling protocol is based on the findings of the YOKI-1 study (protocol number: IPHA-2025-011, Greifswald Ethics Committee Registration number BB 069/25). At baseline, an additional blood sample will be collected for a random determination of solanidine and its metabolites. During the 2.5-hour stay in the CRU, participants will be asked to stay in bed.

Potato Part:

Between the Potato and the Yohimbine Part, a period of 4 weeks in any order is acceptable. The Potato Part is divided into two sequential phases: Phase 1 and Phase 2, both featuring supervised meal ingestion at the clincal research unit. During the three days before each Potato Phase and up to 60 hours afterward, no potato products should be eaten. Otherwise, ad libitum food intake is permitted beginning six hours after the potato-rich meal. Blood samples will be analyzed for solanidine, its CYP2D6-dependent metabolites, and its parent molecules α-solanine and α-chaconine in both Potato Phases. Both Potato Phases must be separated by at least one week.

Phase 1 (0-12 hours postprandial):

An initial baseline blood sample will be collected prior to the ingestion of the potato-rich meal. Participants will receive the potato-rich meal at 8 a.m., and a total of 7 blood samples will be collected at defined time points (baseline, 2, 4, 6, 8, 10, and 12 h).Upon successful completion of the 12-hour blood draw, participants will be discharged from the CRU.

Phase 2 (12-60 hours postprandial):

On a separate scheduled study day, participants will report to the CRU at 7:30 p.m. A baseline blood sample will be collected prior to meal ingestion. Participants will then ingest an identical, defined potato-rich meal at 8:00 p.m. Following meal consumption, participants are permitted to go home for the night. The next morning, starting at 7:30 a.m., blood sampling collections will begin at the designated time points. A total of ten blood samples will be collected at defined time points (baseline, 12, 14, 16, 18, 20, 22, 24 h, 36 h in the next morning and at 60 h in the morning thereafter).

Being tested
Yohimbine, Consumption of a defined potato-rich meal
Keywords
genetic polymorphisms, pharmacokinetics, CYP2D6, yohimbine, drug metabolism, solanidine

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • YohimbineDietary supplement

    A single oral dose of 50 µg yohimbine, administered as 2 x 1 tablets of Yohimbinum hydrochloricum D4® will be administered as drinking solution with 240mL of water under overnight fasting conditions. A total of 6 blood samples will be collected at defined time points (baseline; 10; 20; 30; 60; 120 min). At each time point, 5 mL of blood will be drawn for plasma separation to determine yohimbine and the primary metabolite 11-OH-yohimbine.

  • Consumption of a defined potato-rich mealOther

    Also called potato-rich meal, potato

    Potato Intervention (2 phases):

    Diet restriction: No potato products 3 days before and until 60h after each meal. Ad libitum food intake is allowed from 6h post-meal. Blood will be analyzed for solanidine, its metabolites and its parent molecules α-solanine, and α-chaconine.

    Phase 1 (0-12h postprandial): Baseline blood draw at 8:00 AM, followed by supervised ingestion of a potato-rich meal. A total of 7 blood samples will be collected (baseline, 2, 4, 6, 8, 10, 12h) before discharge from the CRU.

    Phase 2 (12-60h postprandial): Baseline blood draw at 7:30 PM, identical meal ingestion at 8:00 PM. Participants can go home afterwards and return to the CRU the next morning at 8:00 AM for their 12 hour post meal blood draw. A total of 10 blood samples will be collected (baseline, 12, 14, 16, 18, 20, 22, 24h, 36h next morning, 60h subsequent morning).

Study groups in NCT07817030
Study groupRoleWhat they receive
Poor Metabolizers (PM):Active comparatorParticipants in this arm are classified as poor metabolizers (PM, Gene-Score 0) based on their CYP2D6 genotype. Poor metabolizers are homozygous or compound heterozygous for CYP2D6 *3, CYP2D6 *4, CYP2D6 *5, CYP2D6 *6. Participants were selected to achieve best matching between arms according to age, BMI, alcohol consumption and smoking.
Receives: Dietary Supplement: Yohimbine; Other: Consumption of a defined potato-rich meal
Low Intermediate Metabolizer (LIM)Active comparatorLow intermediae metabolizers (LIM, Gene-Score 0,25 or 0,5) are homozygous or compound heterozygous for CYP2D6 *9, *10, *41 or compound heterozygous with one allele of CYP2D6 *3, CYP2D6 *4, CYP2D6*5, or CYP2D6 *6 and one allele of CYP2D6 *17 (0,5) or CYP2D6 *9, *10, or *41 (0,25). Participants were selected to achieve best matching between arms according to age, BMI, alcohol consumption and smoking.
Receives: Dietary Supplement: Yohimbine; Other: Consumption of a defined potato-rich meal
Extensive Metabolizer (EM)Active comparatorExtensive Metabolizer (EM, Gene-Score 2) are homozygous or compound heterozygous for CYP2D6 *1, CYP2D6 *2, CYP2D6*35. Participants were selected to achieve best matching between arms according to age, BMI, alcohol consumption and smoking.
Receives: Dietary Supplement: Yohimbine; Other: Consumption of a defined potato-rich meal
Ultrarapid MetabolizerActive comparatorUltrarapid Metabolizer (UM, Gen-Score ≥ 3) are homozygous or compound heterozygous for CYP2D6 *1, CYP2D6 *2, CYP2D6*35 with at least one allele duplicated or multiplied. Participants were selected to achieve best matching between arms according to age, BMI, alcohol consumption and smoking.
Receives: Dietary Supplement: Yohimbine; Other: Consumption of a defined potato-rich meal

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Metabolic ratio of SSDA/solanidine

    This study determines the sensitivity of the metabolic ratio of SSDA/solanidine and the metabolic ratio of m414/solanidine to correctly identify the CYP2D6 metabolizer status. Each MR will be considered separately in order to identify the most suitable one. As we will recruit individuals from the lowest and highest level of CYP2D6 activity, we will test the sensitivity independently for the prediction of the lowest activity level (PM + LIM) and the highest activity level (EM + UM). The "true" CYP2D6 metabolizer status will be determined by the combination of the CYP2D6 genotype and the yohimbine-determined phenotype in recruited individuals. Those individuals with a perfect match of genotype and phenotype are considered the controls to which the solanidine results are then compared as the ratio of phenotype predicted (by solandine MR)/ phenotype determined (by genotyping + yohimbine-phenotyping)

    Measured: From enrollment to 60 hours after eating the potato-rich meal.

Secondary outcomes (3)
  1. AUC for solanidine, SSDA, m414, α-solanine and α-chaconine

    Plasma concentrations expressed as area under the curve (AUC) will be determined for solanidine, its CYP2D6-dependent metabolites SSDA and m414, and its parent molecules α-solanine and α-chaconine for each metabolizer status cohort (PM, LIM, EM, UM).

    Measured: 60 hours

  2. Cmax for solanidine, SSDA, m414, α-solanine and α-chaconine

    The maximum concentration (Cmax) will be determined for solanidine, its CYP2D6-dependent metabolites SSDA and m414, and its parent molecules α-solanine and α-chaconine for each metabolizer status cohort (PM, LIM, EM, UM).

    Measured: 60 hours

  3. Tmax for solanidine, SSDA, m414, α-solanine and α-chaconine

    Time to maximum concentration (tmax) of solanidine, its CYP2D6-dependent metabolites SSDA and m414, and its parent molecules α-solanine and α-chaconine will be determined for each metabolizer status cohort (PM, LIM, EM, UM).

    Measured: 60 hours

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted14 Sep 2026
  2. Study start21 Sep 2026 (estimated)
  3. Primary completion30 Sep 2027 (estimated)
  4. Study completion31 Dec 2027 (estimated)

Resources

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 N/A
Primary purpose
Basic science
Allocation
Non-randomised
Intervention model
Parallel groups
Model description
The study is designed as an open-label, controlled, parallel-cohort design with four study arms based on CYP2D6 genotype.
Masking
None (open label)
Enrolment
30 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07817030
Sponsor's protocol ID
IPHA-2026-12
Acronym
SOLA-1
Status last verified
Sep 2026
First submitted
8 Sep 2026
Last updated
14 Sep 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A study testing Yohimbine and Consumption of a defined potato-rich meal in people with Pharmacokinetic Study in Healthy Volunteers, run by University Medicine Greifswald at 1 site in Germany.

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 16 inclusion and 18 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: opening soon, as of the sponsor's last update on 14 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 Germany. 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.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Stefan Engeli, Prof. Dr. (+49 3834 86 5633, stefan.engeli@med.uni-greifswald.de), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Metabolic ratio of SSDA/solanidine (time frame: From enrollment to 60 hours after eating the potato-rich meal.). It is what the study was designed to measure, not a finding.

Where can I read the original study information?
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 14 Sep 2026.

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