A Study Of Pregabalin (Lyrica) Drug Levels In Urine, Plasma And Breast Milk Of Healthy Lactating Women

Area under the plasma concentration-time profile from time 0 to tau (AUCtau), where tau was the dosing interval of 12 hours.

Cmax was the peak concentration in plasma post Day 3 dose.

Tmax was the time to peak concentration in plasma post Day 3 dose.

Plasma decay half-life (t1/2) was the time for the plasma concentration to decrease by one-half. The t1/2 is based on the terminal elimination phase time points from this timeframe.

Average plasma concentration during the dosing interval (Cav) was calculated by dividing AUCtau (plasma) with tau, where tau was the dosing interval of 12 hours.

Cmin was the minimum observed plasma concentration of a drug after post Day 3 dose.

Apparent oral clearance (CL/F) was calculated by dividing dose by the AUCtau, where tau was the dosing interval of 12 hours. Clearance of a drug is a measure of the rate at which a drug is metabolized or eliminated by normal biological processes. Clearance obtained after oral dose (apparent oral clearance) is influenced by the fraction of the dose absorbed. Drug clearance is a quantitative measure of the rate at which a drug substance is removed from the blood.

AUCtau (breast milk) was the area under the curve for breast milk, from time 0 to tau (AUCtau), where tau was the dosing interval of 12 hours.

Cmax (breast milk) was the maximum observed concentration in breast milk post Day 3 dose.

Tmax (breast milk) was time of the maximum observed breast milk concentration Day 3 post-dose.

The terminal half-life for breast milk (t1/2 [breast milk]) was the time measured for breast milk concentration to decrease by one-half. For the first 5 participants enrolled under protocol amendment dated: 18 Sep 2012, breast milk was collected up to 24 hours after Day 3 dosing over the following time intervals: 0 to 2, 2 to 4, 4 to 8, 8 to 12, 12 to 24 hours. Terminal half-life was determined over those points characterizing the elimination phase. For the remaining 5 participants, there were 3 additional collection intervals (24 to 32, 32 to 40, 40 to 48 hours) for characterizing the terminal elimination phase. The t1/2 (breast milk) is based on the terminal elimination phase time points from this timeframe.

Average breast milk concentration during the dosing interval (Cav) was calculated by dividing AUCtau (breast milk) with tau, where tau was the dosing interval of 12 hours.

Aetaubm was the amount excreted in breast milk over the dosing interval tau (12 hours). It was calculated as the sum of (breast milk concentration * sample volume) for each collection interval from 0 to 12 hours post-dose, where tau was the dosing interval of 12 hours. Sample volume was based on ratio of volume weight and density.

Percentage of dose excreted in breast milk during the dosing interval tau (Aetaubm percent) was calculated by using the formula: 100*(Aetaubm [sum of {breast milk concentration * sample volume} for each collection interval from 0 to 12 hours post-dose] divided by dose), where tau was the dosing interval of 12 hours.

Breast milk clearance (CLbm) was calculated by dividing Aetaubm (sum of [breast milk concentration * sample volume] for each collection interval from 0 to 12 hours post-dose) by plasma AUCtau, where tau was the dosing interval of 12 hours.

Aetauurine was the amount excreted in urine over the dosing interval tau (12 hours). It was calculated as the sum of (urine concentration * sample volume) for each collection interval from 0 to 12 hours post-dose, where tau was the dosing interval of 12 hours. Here, sample volume was based on the ratio of volume weight and density.

Percent of dose recovered in urine during the dosing interval tau (Aetauurine percent) was calculated as 100* (Aetau [sum of {urine concentration * sample volume} for each collection interval from 0 to 12 hours post-dose] divided by the dose), where tau was the dosing interval of 12 hours.

Renal clearance (CLr) was the volume of plasma from which the drug was completely removed by the kidney in a given amount of time. It was calculated by dividing Aetauurine (sum of [urine concentration * sample volume] for each collection interval from 0 to 12 hours post-dose) with the plasma AUCtau, where tau was the dosing interval of 12 hours.

Ae24bm was the daily amount of pregabalin excreted in breast milk. It was calculated by the formula: 2 * Aetaubm (sum of [breast milk concentration * sample volume] for each collection interval from 0 to 12 hours post-dose), where tau was the dosing interval of 12 hours.

MPAUCtau was the ratio of AUCtau (breast milk) to AUCtau (plasma), where tau was the dosing interval of 12 hours.

Milk to plasma ratio for maximum observed concentration (MPCmax) was calculated as the ratio of Cmax (breast milk) to Cmax (plasma).

Body weight normalized infant dose (BWNID) of pregabalin was the dose that an infant received from breast-feeding and was calculated from the milk to plasma AUCtau ratio multiplied by the average maternal plasma pregabalin concentration (Cav) multiplied by the standardized milk consumption for an infant (150 milliliter/kilogram/day [mL/kg/day]), where tau was the dosing interval of 12 hours.

Body weight normalized maternal dose (BWNMD) was calculated as the maternal dose in microgram per day (mcg/day) divided by maternal weight in kilogram (kg) at screening.

Infant dose expressed as percentage of body weight normalized maternal dose (BWNIDPCM) was the relative infant dose (relative to maternal dose) calculated by the formula: 100 * BWNID (Body Weight Normalized Infant Dose) / Body Weight Normalized Maternal Dose (BWNMD), where tau was the dosing interval of 12 hours.

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. An SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. Treatment-emergent are events between first dose of study drug and up to 28 days after last dose that were absent before treatment or that worsened relative to pretreatment state. AEs included both SAEs and non-SAEs.

The following parameters were analyzed for laboratory abnormalities: hematology (hemoglobin, hematocrit, red blood cell count, mean corpuscular volume [MCV], mean corpuscular hemoglobin [MCH], mean corpuscular hemoglobin concentration [MCHC], platelets, white blood cell count, lymphocytes, total neutrophils, basophils, eosinophils, monocytes); liver function (bilirubin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total protein, albumin); renal function (blood urea nitrogen, creatinine, uric acid); electrolytes (sodium, potassium, chloride, calcium, bicarbonate); clinical chemistry (glucose); urinalysis (urine pH, glucose, ketones, protein, urine blood/hemoglobin, nitrite).

The following parameters were analyzed for examination of vital signs: electrocardiogram (ECG), systolic and diastolic blood pressure, temperature, pulse rate, respiratory rate, radial pulse and body temperature.