This is a Phase I, randomized, double-blind, placebo-controlled, single-center, dose-escalation study to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of HW243040 in healthy participants. The study consists of two parts: Part A (Single Ascending Dose, SAD) and food effect study, and Part B (Multiple Ascending Dose, MAD). A total of approximately 98 healthy participants will be enrolled.
This is a first-in-human, Phase I, randomized, double-blind, placebo-controlled, single-center, dose-escalation clinical trial designed to evaluate the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of HW243040, a novel angiotensin II type 2 receptor (AT2R) antagonist, in healthy participants. Preclinical data have demonstrated that HW243040 exhibits good analgesic efficacy in neuropathic pain models with a favorable safety profile, supporting its further clinical development. This study does not aim to explore the maximum tolerated dose (MTD) but focuses on characterizing the safety and PK profile across a range of doses. The study is divided into two main parts: Part A (Single Ascending Dose, SAD, combined with a Food Effect evaluation) and Part B (Multiple Ascending Dose, MAD) . A total of approximately 98 healthy participants are planned for enrollment across both parts. Part A: SAD and Food Effect Study Part A consists of 6 dose cohorts: 50 mg, 150 mg, 300 mg, 600 mg, 900 mg, and 1200 mg. Except for the 600 mg cohort, each cohort enrolls 10 participants (8 receiving active HW243040 and 2 receiving placebo) under fasting conditions. The 600 mg cohort enrolls 18 participants (16 active, 2 placebo) and utilizes a two-period, two-sequence crossover design to evaluate the effect of a high-fat, high-calorie meal on the PK of HW243040. In this cohort, participants receive the study drug under fasting conditions in one period and under fed conditions in the other, with a 7-day washout between periods. Dose escalation proceeds sequentially from the lowest to the highest dose, with dose progression decisions made by a Safety Review Committee (SRC) based on review of safety and available PK data from the preceding cohort. Dose escalation will be halted if predefined stopping criteria are met (e.g., ≥1/2 participants with moderate related AEs, ≥1/3 with severe related AEs, or any related SAE). Part B: MAD Study Based on the safety and PK results from Part A, Part B evaluates three dose levels of HW243040 administered twice daily (BID). The planned dose levels are 150 mg, 300 mg, and 600 mg BID. Each cohort enrolls 10 participants (8 active, 2 placebo). Participants receive the study drug for 5 consecutive days (morning and evening, approximately 12 hours apart, for a total of 9 administrations, with only the morning dose given on Day 5). The final dosing regimen, duration, and sampling schedule for Part B may be adjusted based on emerging data from Part A. Study Population: Healthy male and female participants aged 18 to 55 years, with a body mass index (BMI) between 19 and 26 kg/m², and body weight ≥50 kg for males and ≥45 kg for females. Participants must be willing to undergo pain testing procedures and comply with the study requirements. Intervention and Blinding: HW243040 is formulated as oral tablets in 50 mg and 200 mg strengths. Matching placebo tablets are provided. The study is double-blinded; participants, investigators, site staff, and outcome assessors will be blinded to treatment allocation. Randomization is performed using a block randomization method with a 8:2 (active:placebo) ratio for most cohorts (and 8:1 for the 600 mg SAD cohort). Study Procedures and Assessments: The study comprises a screening period (Day -7 to Day -1), a treatment/observation period, and a follow-up period (for unresolved AEs). Safety Assessments: Include monitoring of adverse events (AEs), serious adverse events (SAEs), vital signs, physical examinations, 12-lead electrocardiograms (ECGs), clinical laboratory tests (hematology, biochemistry, urinalysis, coagulation, and thyroid function), and pregnancy tests for females of childbearing potential. A C-QTc sub-study is planned for cohorts at doses ≥300 mg (including the 600 mg cohort, Sequence A only) to explore the relationship between HW243040 plasma concentrations and changes in QTcF interval. Pharmacokinetic Assessments: SAD/FE (non-600mg cohorts): Blood samples are collected at 13 time points from pre-dose to 72 hours post-dose. SAD/FE (600mg cohort): Blood samples are collected at 26 time points across two periods (up to 72 hours post-dose per period). MAD: Blood samples are collected on Day 1 (pre-dose to 12 hours), pre-dose on Days 3, 4, and 5, and intensively on Day 5 up to 72 hours post final dose (25 time points total). Urine and Feces (Exploratory): Full urine and fecal samples are collected from participants in Sequence A of the 600 mg cohort during the first period for metabolite profiling and excretion mass balance exploration. Pharmacodynamic Assessments: PD evaluations are performed using standardized pain tests, including Pressure Pain Threshold (PPT) measured by a pressure algometer and Pain Tolerance Time (PTT) measured by the cold pressor test (immersion of hand in ice water, maximum 120 seconds). PD assessments are conducted at pre-dose and at 1, 2, 4, 6, 8, and 12 hours post-dose. Pharmacokinetic Parameters: Key PK parameters calculated using non-compartmental analysis include: C\~max\~, T\~max\~, AUC\~0-t\~, AUC\~0-inf\~, t\~1/2\~, CL/F, and Vz/F (SAD); and additionally C\~trough,ss\~, AUC\~tau,ss\~, and accumulation ratios (R\~ac\~) for MAD. Statistical Analysis: Analyses will be performed using SAS (Version 9.4 or higher). The Safety Analysis Set (SS) will be used for all safety summaries. PK parameters will be summarized descriptively by dose group. For the food effect evaluation, a linear mixed-effects model (with sequence, period, and treatment as fixed effects and participant as random effect) will be applied to log-transformed exposure parameters (AUC\~0-t\~, AUC\~0-inf\~, C\~max\~) to calculate geometric mean ratios and 90% confidence intervals. PD endpoints, C-QTc relationship, and dose proportionality will be explored descriptively or via appropriate modeling approaches (e.g., power model, linear mixed-effects model). Study Duration and Follow-up: Participants will be confined to the clinical unit from Day -1 through the end of the observation period (Day 4 for most SAD cohorts; Day 11 for the 600 mg cohort; Day 8 for MAD cohorts). All participants with ongoing AEs at discharge will be followed until resolution, return to baseline, stabilization, or loss to follow-up. The study is being conducted at a single center, The Third Xiangya Hospital of Central South University, Changsha, China, under the sponsorship of Hubei Bio-Pharmaceutical Industrial Technology Research Institute Co., Ltd.
HW243040 tablets, 50mg and 200mg规格, administered orally. Doses range from 50mg to 1200mg as a single dose in Part A, or 150mg to 600mg twice daily for 5 days in Part B. Administered with 240mL water under fasting or fed (high-fat, high-calorie meal) conditions as specified per arm.
HW243040 matching placebo tablets, 50mg and 200mg规格, identical in appearance to HW243040 active tablets. Administered orally with 240mL water under the same conditions as the corresponding active dose arm.
Incidence of Treatment-Emergent Adverse Events (TEAEs)
Number of participants with TEAEs, including serious adverse events (SAEs), assessed by CTCAE v5.0.
Time frame: From signing of informed consent form through follow-up period (until AE resolution; up to Day 4 for SAD 50/150/300/900/1200 mg, Day 11 for 600 mg FE, Day 8 for MAD cohorts).
Number of Participants with Clinically Significant Vital Signs Changes
Time frame: Baseline (Day -1) to End of Study; measured at screening, Day -1, pre-dose and 1, 2, 4, 8, 12, 24, 48, 72 hours post-dose (schedule varies per cohort).
Number of Participants with Clinically Significant Laboratory Abnormalities
Time frame: Baseline (Screening) to End of Study (Day 4 for SAD 50/150/300/900/1200 mg; Day 11 for 600 mg FE; Day 8 for MAD).
Number of Participants with Clinically Significant 12-lead ECG Abnormalities
Time frame: Baseline (Day -1) to End of Study; measured at screening, Day -1, pre-dose and 1, 2, 4, 8, 12, 24, 48, 72 hours post-dose (schedule varies per cohort).
Maximum Observed Plasma Concentration (Cmax) Following Single Ascending Dose Administration
Cmax of HW243040 in plasma following single ascending dose administration, measured by validated LC-MS/MS method.
Time frame: Day 1: pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72 hours post-dose.
Time to Maximum Observed Plasma Concentration (Tmax) of HW243040 Following Single Ascending Dose Administration
Tmax of HW243040 in plasma following single ascending dose administration, determined directly from concentration-time data.
Time frame: Day 1: pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72 hours post-dose.
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Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
TRIPLE
Enrollment
98
Apparent Terminal Elimination Half-life (t1/2) of HW243040 Following Single Ascending Dose Administration
Terminal elimination half-life of HW243040 in plasma following single ascending dose administration, calculated as ln(2)/λz.
Time frame: Day 1: pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72 hours post-dose.
Area Under the Plasma Concentration-Time Curve from Time Zero to Last Measurable Concentration (AUC0-t) of HW243040 Following Single Ascending Dose Administration
AUC0-t of HW243040 in plasma following single ascending dose administration, calculated using the linear-up/log-down trapezoidal method. Unit: h\*ng/mL.
Time frame: Day 1: pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72 hours post-dose.
Area Under the Plasma Concentration-Time Curve from Time Zero Extrapolated to Infinity (AUC0-inf) of HW243040 Following Single Ascending Dose Administration
AUC0-inf of HW243040 in plasma following single ascending dose administration, calculated as AUC0-t + Clast/λz.
Time frame: Day 1: pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72 hours post-dose.
Apparent Total Clearance (CL/F) of HW243040 Following Single Ascending Dose Administration
Apparent total clearance of HW243040 from plasma following single ascending dose administration, calculated as Dose/AUC0-inf.
Time frame: Day 1: pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72 hours post-dose.
Apparent Volume of Distribution (Vz/F) of HW243040 Following Single Ascending Dose Administration
Apparent volume of distribution of HW243040 during the terminal phase following single ascending dose administration, calculated as Dose/(AUC0-inf × λz).
Time frame: Day 1: pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72 hours post-dose.
Maximum Observed Plasma Concentration (Cmax) of HW243040 Following Single Dose in Fed and Fasted States
Cmax of HW243040 in plasma following single dose in fed and fasted states, measured by validated LC-MS/MS method.
Time frame: Period 1 (Day 1) and Period 2 (Day 8): pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72 hours post-dose in each period (two-way crossover, fasted vs fed).
Time to Maximum Observed Plasma Concentration (Tmax) of HW243040 Following Single Dose in Fed and Fasted States
Tmax of HW243040 in plasma following single dose in fed and fasted states.
Time frame: Period 1 (Day 1) and Period 2 (Day 8): pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72 hours post-dose in each period (two-way crossover, fasted vs fed).
Apparent Terminal Elimination Half-life (t1/2) of HW243040 Following Single Dose in Fed and Fasted States
Terminal elimination half-life of HW243040 in plasma following single dose in fed and fasted states, calculated as ln(2)/λz.
Time frame: Period 1 (Day 1) and Period 2 (Day 8): pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72 hours post-dose in each period (two-way crossover, fasted vs fed).
Area Under the Plasma Concentration-Time Curve from Time Zero to Last Measurable Concentration (AUC0-t) of HW243040 Following Single Dose in Fed and Fasted States
AUC0-t of HW243040 in plasma following single dose in fed and fasted states, calculated by linear-up/log-down trapezoidal method.
Time frame: Period 1 (Day 1) and Period 2 (Day 8): pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72 hours post-dose in each period (two-way crossover, fasted vs fed).
Area Under the Plasma Concentration-Time Curve from Time Zero Extrapolated to Infinity (AUC0-inf) of HW243040 Following Single Dose in Fed and Fasted States
AUC0-inf of HW243040 in plasma following single dose in fed and fasted states, calculated as AUC0-t + Clast/λz.
Time frame: Period 1 (Day 1) and Period 2 (Day 8): pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72 hours post-dose in each period (two-way crossover, fasted vs fed).
Apparent Total Clearance (CL/F) of HW243040 Following Single Dose in Fed and Fasted States
Apparent total clearance of HW243040 in plasma following single dose in fed and fasted states, calculated as Dose/AUC0-inf.
Time frame: Period 1 (Day 1) and Period 2 (Day 8): pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72 hours post-dose in each period (two-way crossover, fasted vs fed).
Apparent Volume of Distribution (Vz/F) of HW243040 Following Single Dose in Fed and Fasted States
Apparent volume of distribution of HW243040 in plasma following single dose in fed and fasted states, calculated as Dose/(AUC0-inf × λz).
Time frame: Period 1 (Day 1) and Period 2 (Day 8): pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24, 48, 72 hours post-dose in each period (two-way crossover, fasted vs fed).
Maximum Observed Plasma Concentration (Cmax) of HW243040 on Day 1 of Multiple Ascending Dose Administration
Cmax of HW243040 in plasma on Day 1 after the first dose of multiple ascending dose administration, measured by validated LC-MS/MS method.
Time frame: Day 1: pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-dose (12-hour sample is pre-dose for second administration).
Time to Maximum Observed Plasma Concentration (Tmax) of HW243040 on Day 1 of Multiple Ascending Dose Administration
Tmax of HW243040 in plasma on Day 1 after the first dose of multiple ascending dose administration.
Time frame: Day 1: pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-dose (12-hour sample is pre-dose for second administration).
Area Under the Plasma Concentration-Time Curve from Time Zero to 12 Hours (AUC0-12h) of HW243040 on Day 1 of Multiple Ascending Dose Administration
AUC0-12h of HW243040 in plasma on Day 1, calculated by linear-up/log-down trapezoidal method.
Time frame: Day 1: pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-dose (12-hour sample is pre-dose for second administration).
Area Under the Plasma Concentration-Time Curve from Time Zero Extrapolated to Infinity (AUC0-inf) of HW243040 on Day 1 of Multiple Ascending Dose Administration
AUC0-inf of HW243040 in plasma on Day 1, calculated as AUC0-t + Clast/λz.
Time frame: Day 1: pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-dose (12-hour sample is pre-dose for second administration).
Apparent Total Clearance (CL/F) of HW243040 on Day 1 of Multiple Ascending Dose Administration
Apparent total clearance of HW243040 on Day 1, calculated as Dose/AUC0-inf.
Time frame: Day 1: pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-dose (12-hour sample is pre-dose for second administration).
Apparent Volume of Distribution (Vz/F) of HW243040 on Day 1 of Multiple Ascending Dose Administration
Apparent volume of distribution of HW243040 on Day 1, calculated as Dose/(AUC0-inf × λz).
Time frame: Day 1: pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-dose (12-hour sample is pre-dose for second administration).
Apparent Terminal Elimination Half-life (t1/2) of HW243040 on Day 1 of Multiple Ascending Dose Administration
Terminal elimination half-life of HW243040 on Day 1, calculated as ln(2)/λz.
Time frame: Day 1: pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-dose (12-hour sample is pre-dose for second administration).
Area Under the Plasma Concentration-Time Curve over One Dosing Interval (AUC0-tau) of HW243040 on Day 1 of Multiple Ascending Dose Administration
AUC0-tau of HW243040 in plasma on Day 1, covering the 12-hour dosing interval, calculated by linear-up/log-down trapezoidal method.
Time frame: Day 1: pre-dose (within 30 minutes) and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-dose (12-hour sample is pre-dose for second administration).
Area Under the Plasma Concentration-Time Curve over a Dosing Interval at Steady State (AUCtau,ss) of HW243040
AUC over one dosing interval at steady state on Day 5 of multiple ascending dose administration, calculated by linear-up/log-down trapezoidal method.
Time frame: Day 3, Day 4, and Day 5: pre-dose (morning troughs); Day 5: pre-dose and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-morning dose; plus 24 hours (Day 6), 48 hours (Day 7), and 72 hours (Day 8) post-morning dose on Day 5.
Area Under the Plasma Concentration-Time Curve from Time Zero to Last Measurable Concentration at Steady State (AUC0-t,ss) of HW243040
AUC0-t at steady state on Day 5 of multiple ascending dose administration, calculated by linear-up/log-down trapezoidal method.
Time frame: Day 3, Day 4, and Day 5: pre-dose (morning troughs); Day 5: pre-dose and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-morning dose; plus 24 hours (Day 6), 48 hours (Day 7), and 72 hours (Day 8) post-morning dose on Day 5.
Area Under the Plasma Concentration-Time Curve from Time Zero Extrapolated to Infinity at Steady State (AUC0-inf,ss) of HW243040
AUC0-inf at steady state on Day 5 of multiple ascending dose administration, calculated as AUC0-t + Clast/λz.
Time frame: Day 3, Day 4, and Day 5: pre-dose (morning troughs); Day 5: pre-dose and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-morning dose; plus 24 hours (Day 6), 48 hours (Day 7), and 72 hours (Day 8) post-morning dose on Day 5.
Time to Maximum Observed Plasma Concentration at Steady State (Tmax,ss) of HW243040
Tmax at steady state on Day 5 of multiple ascending dose administration.
Time frame: Day 3, Day 4, and Day 5: pre-dose (morning troughs); Day 5: pre-dose and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-morning dose; plus 24 hours (Day 6), 48 hours (Day 7), and 72 hours (Day 8) post-morning dose on Day 5.
Apparent Terminal Elimination Half-life (t1/2) of HW243040 at Steady State
Terminal elimination half-life at steady state on Day 5 of multiple ascending dose administration, calculated as ln(2)/λz.
Time frame: Day 3, Day 4, and Day 5: pre-dose (morning troughs); Day 5: pre-dose and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-morning dose; plus 24 hours (Day 6), 48 hours (Day 7), and 72 hours (Day 8) post-morning dose on Day 5.
Apparent Clearance at Steady State (CLss/F) of HW243040
Apparent clearance at steady state on Day 5 of multiple ascending dose administration, calculated as Dose/AUCtau,ss.
Time frame: Day 3, Day 4, and Day 5: pre-dose (morning troughs); Day 5: pre-dose and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-morning dose; plus 24 hours (Day 6), 48 hours (Day 7), and 72 hours (Day 8) post-morning dose on Day 5.
Apparent Volume of Distribution at Steady State (Vz/F) of HW243040
Apparent volume of distribution at steady state on Day 5 of multiple ascending dose administration, calculated as Dose/(AUCtau,ss × λz).
Time frame: Day 3, Day 4, and Day 5: pre-dose (morning troughs); Day 5: pre-dose and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-morning dose; plus 24 hours (Day 6), 48 hours (Day 7), and 72 hours (Day 8) post-morning dose on Day 5.
Trough Concentration at Steady State (Ctrough,ss) of HW243040
Trough plasma concentration at steady state on Day 5 of multiple ascending dose administration.
Time frame: Day 3, Day 4, and Day 5: pre-dose (morning troughs); Day 5: pre-dose and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-morning dose; plus 24 hours (Day 6), 48 hours (Day 7), and 72 hours (Day 8) post-morning dose on Day 5.
Peak Concentration at Steady State (Cmax,ss) of HW243040
Peak plasma concentration at steady state on Day 5 of multiple ascending dose administration.
Time frame: Day 3, Day 4, and Day 5: pre-dose (morning troughs); Day 5: pre-dose and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-morning dose; plus 24 hours (Day 6), 48 hours (Day 7), and 72 hours (Day 8) post-morning dose on Day 5.
Accumulation Ratio (Rac) of HW243040 at Steady State
Accumulation ratio based on AUC (Rac,AUC) and Cmax (Rac,Cmax) at steady state on Day 5 of multiple ascending dose administration.
Time frame: Day 3, Day 4, and Day 5: pre-dose (morning troughs); Day 5: pre-dose and 0.25, 0.5, 1, 1.5, 2, 4, 6, 8, 12 hours post-morning dose; plus 24 hours (Day 6), 48 hours (Day 7), and 72 hours (Day 8) post-morning dose on Day 5.
Cumulative Amount of Unchanged HW243040 Excreted in Urine (Ae)
Cumulative amount of unchanged HW243040 excreted in urine, measured by validated LC-MS/MS method.
Time frame: Period 1 (Day 1): pre-dose (within 12 hours) and 0-4, 4-8, 8-12, 12-24, 24-48, 48-72 hours post-dose.
Cumulative Amount of Unchanged HW243040 Excreted in Feces (Ae)
Cumulative amount of unchanged HW243040 excreted in feces, measured by validated LC-MS/MS method.
Time frame: Period 1 (Day 1): pre-dose (within 12 hours) and 0-4, 4-8, 8-12, 12-24, 24-48, 48-72 hours post-dose.
Fraction of Unchanged HW243040 Excreted in Urine (fe)
Fraction of unchanged HW243040 excreted in urine, calculated as Ae/dose.
Time frame: Period 1 (Day 1): pre-dose (within 12 hours) and 0-4, 4-8, 8-12, 12-24, 24-48, 48-72 hours post-dose.
Fraction of Unchanged HW243040 Excreted in Feces (fe)
Fraction of unchanged HW243040 excreted in feces, calculated as Ae/dose.
Time frame: Period 1 (Day 1): pre-dose (within 12 hours) and 0-4, 4-8, 8-12, 12-24, 24-48, 48-72 hours post-dose.
Renal Clearance (CLR) of HW243040
Renal clearance of HW243040, calculated as cumulative amount excreted in urine divided by AUC.
Time frame: Period 1 (Day 1): pre-dose (within 12 hours) and 0-4, 4-8, 8-12, 12-24, 24-48, 48-72 hours post-dose.