Intervention: Diclofenac
Trial phase: Phase 1
ATC code: D11AX18 | M01AB05 | M01AB55 | M02AA15 | S01BC03 | S01CC01
SMILES: O=C(O)Cc1ccccc1Nc1c(Cl)cccc1Cl
Sex: Male
Age groups: Adult | Older Adult
Healthy volunteers: Accepts Healthy Volunteers
Participants at risk: 20
Group description: Cohort 2: Diclofenac, DCF100 gel (4% w/w)

Diclofenac: Subjects were randomised to receive 22 uL (20 ± l mg) DCF100 Gel (diclofenac 2% w/w) / DCF100 Gel (diclofenac 4% w/w) / Matching Placebo DCF100 Gel / Voltarol® 12 Hour Emulgel® P 2.32% Gel. The gels were administered topically on two test sites on the lower back of the subject, each 1.76 cm2 in size. The two test sites were UVB irradiated on the previous day, between 22 and 26 hours (24 ± 2 hours) before dosing.
Eligibility criteria:
Inclusion Criteria:

Were able to provide written informed consent.
Male between 18 and 65 years old, inclusive, at the time of screening.
Good general health as ascertained by detailed medical history and physical examination.
Body mass index (BMI) ≥18 and ≤29 kg/m2 (BMI = weight/height2), at the time of screening.
No clinically relevant abnormalities in 12-lead ECG as per PI's judgement, e.g., absence of cardiac rhythm disorder, in particular bradycardia (<40 beats per minute), conduction abnormalities such as atrioventricular block, absence of active ischemia (such as unstable angina pectoris) or recent myocardial infarction, no QTcF interval >450 milliseconds, no QRS complex ≥120 milliseconds, at Screening.
No clinically relevant abnormalities in results of laboratory tests as per PI's judgement; in particular, no significant liver impairment defined as aspartate aminotransferase (AST), alanine aminotransferase (ALT) 1.5x upper limit of normal (ULN); no significant kidney impairment defined as serum creatinine 2x ULN; abnormal thyroid function as defined by thyroid-stimulating hormone (TSH) and total thyroxin (T4) (TSH within range 0.27 to 4.2 mIU/L, total T4 within range 59 to 154 nmol/L).
Had a skin type II or III (Fitz Patrick classification).
Non-smokers or ex-smokers for at least 6 months prior to the Screening Visit, as confirmed by a urine cotinine test.
Subjects were able to communicate well with the PI/designee. -

Exclusion Criteria:

History of hypersensitivity to the IMP or any of the excipients or to medicinal products with similar chemical structures.
Presence of any clinically relevant acute or chronic disease which could interfere with the subject safety during the study, expose the subject to undue risk, limit the biological sampling (e.g., blood collection), interfere with the absorption of the IMP (e.g., active dermatological conditions at the application sites, or ulcers, irritable bowel syndrome) or interfere with the study objectives.
Skin type I, IV, V or VI (Fitzpatrick Classification).
History of chronic pain symptoms (>6 months) or ongoing pain.
Any condition that required regular concomitant medication including herbal products, or predicted need of any concomitant medication from Screening Visit until the end of the study.
Intake of any medication including over the counter (OTC) medication (in particular any pain killers), herbal and dietary supplements such as St John's Wort, vitamins and minerals that could affect the outcome of the study, within 48 hours before the first administration of the investigational product and for the duration of the study.
Use of photosensitising medication, such as phenothiazines, tetracyclines, quinolones, sulphonamides, nalidixic acid, non-steroidal anti-inflammatories, furosemides, hydrochlorothiazides, fibrate, phytotherapeutic drugs (herbal supplements), phenothiazines, quinidines, psoralens and amiodarone within 4 weeks before the first UVB irradiation and for the duration of the study.
Any skin disease, acute or chronic (e.g., psoriasis vulgaris, neurodermatitis) or auto immune diseases associated with increased light sensitisation.
Any active dermatological conditions, local pigmentary disorders, body art (e.g., tattoos), or excessive hair growth at the lower back that might interfere with the study assessments or absorption of the IMP.
History of skin cancer (i.e., melanoma, squamous cell carcinoma or basal cell carcinoma).
History of conditions that increase risk for melanoma (e.g., dysplastic nevus [>5 nevi], xeroderma pigmentosum, Fanconi anaemia, Bloom's syndrome, Werner syndrome, Cockayne syndrome, trichothiodystrophy, or familial mole melanoma syndrome).
History of bleeding disorders, peptic ulceration or gastro intestinal bleeding, heart burn, cardiovascular disease, myocardial infarction or stroke.
Inability to give reproducible HPPT ratings on naïve skin at screening, (defined as HPTT test re-test difference ≥1.0 °C)
Heat pain perception threshold <40°C or >51°C on naïve skin at Screening.
Supine systolic blood pressure (SBP) <90 mmHg or >140 mmHg, or supine diastolic blood pressure (DBP) <50 mmHg or >90 mmHg after 5 minutes supine, at the Screening Visit.
Positive test results for HBsAg, HCVAb or HIV-1 and/or -2 antibodies at Screening.
Excessive use of caffeine-containing beverages exceeding 500 mg caffeine/day (5 cups of coffee) and the inability to refrain from the use of caffeine-containing beverages during confinement in the Clinical Unit.
Excessive alcohol consumption (regular alcohol intake ≥21 units per week). Use of alcohol 48 hours before any study visit, as confirmed by urine alcohol testing at Screening, Day -2, and with any additional tests at the discretion of the PI.
History in the last year or presence of drug addiction (positive urine drug screen) at Screening and Day -2.
Presence or history of alcohol abuse in the last year, as confirmed by subject's general practitioner (GP).
Blood donation within 8 weeks before the first IMP administration.
Participation in another study with an experimental drug within 3 months before the first dosing day.
Any psychological, emotional problems, any disorder or resultant therapy that was likely to invalidate informed consent, or limited the ability of the subject to comply with the protocol requirements.
Unlikely to comply with the protocol requirements, instructions and study-related restrictions; e.g., uncooperative attitude, inability to return for Follow-up visits and improbability of completing the clinical study.
Planned surgery, dental procedure, or hospitalisation from the Screening Visit until the end of the study.
Inability to give written informed consent or to comply fully with the protocol.

Subjects who, in the opinion of the PI, were considered unsuitable for any other reason.

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