The main objective of this study is to assess the relative systemic bioavailability of diclofenac in the presence and absence of capsaicin by comparing the systemic bioavailability of diclofenac from a combination product (Diclofenac 2% + Capsaicin 0.075% Topical Gel) with two diclofenac only products, Diclofenac Mono Gel 2% and Voltarol® 12 Hour Emulgel 2.32% Gel, following topical administration. In order to examine potential racial differences in pharmacokinetics (PK), the study population will be stratified 50:50, Caucasian versus Black people. With respect to the main objective, additionally a supportive analysis will be performed to investigate the influence of race on the intra-individual bioavailability ratios.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
48
twice daily
twice daily
twice daily
Bloemfontein Early Phase Clinical Unit, PAREXEL International (South Africa)
Bloemfontein, South Africa
Area Under the Plasma Concentration-time Curve (AUC) Over One Dosing Interval for Diclofenac at Steady State (AUC0-τ,ss) (τ = 12 Hours) (Day 7)
AUC0-τ,ss, Area under the plasma concentration-time curve (AUC) over one dosing interval at steady state for diclofenac at day 7 (τ = 12 hours). Stratification by race was analysed using a supportive Analysis of Variance (ANOVA) yielding point estimates for each underlying pairwise comparison analog to the main analysis. As the resulting two Least Square Means and Geometric Means (gMeans) per treatment and race are very similar, only gMeans per treatment and race are presented.
Time frame: Pharmacokinetic samples were collected on Day 7 at pre-dose and 0.5, 1, 2, 3, 4, 6, 8, 10 and 12 hours after the drug administration
Maximum Plasma Concentration During a Dosage Interval (Cmax,ss) Obtained Directly From the Concentration-time Data for Diclofenac at Steady State (Day 7)
Cmax,ss, Maximum plasma of diclofenac concentration during a dosage interval obtained directly from the concentration-time data at steady state for diclofenac on day 7. Stratification by race was analysed using a supportive Analysis of Variance (ANOVA) yielding point estimates for each underlying pairwise comparison analog to the main analysis. As the resulting two Least Square Means and gMeans per treatment and race are very similar, only gMeans per treatment and race are presented.
Time frame: Pharmacokinetic samples were collected on Day 7 at pre-dose and 0.5, 1, 2, 3, 4, 6, 8, 10 and 12 hours after the drug administration
Time to Maximum Observed Plasma Concentration at Steady State for Diclofenac at Steady State (Tmax,ss) (Day 7)
tmax,ss, Time to maximum observed plasma concentration at steady state for diclofenac at day 7 (tmax,ss). Descriptive statistics by race are reported in addition.
Time frame: Pharmacokinetic samples were collected on Day 7 at pre-dose and 0.5, 1, 2, 3, 4, 6, 8, 10 and 12 hours after the drug administration
Average Plasma Concentration (Cav,ss) for Diclofenac at Steady State
Average plasma concentration (Cav,ss) calculated as AUC0-t,ss divided by τ=12 hours (τ is the duration of the dosing interval). Descriptive statistics by race are reported in addition.
Time frame: Pharmacokinetic samples were collected on Day 7 at pre-dose and 0.5, 1, 2, 3, 4, 6, 8, 10 and 12 hours after the drug administration
Percentage Peak-trough Fluctuation (%PTF), Calculated as [100*(Cmax,ss - Cpre,ss)/Cav,ss]
Percentage peak-trough fluctuation (%PTF) which was calculated as \[100\*(Cmax,ss - Cpre,ss)/Cav,ss\] for Diclofenac. Descriptive statistics by race are reported in addition.
Time frame: Pharmacokinetic samples were collected on Day 7 at pre-dose and 0.5, 1, 2, 3, 4, 6, 8, 10 and 12 hours after the drug administration
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