Post by Amtram on Mar 1, 2014 13:03:06 GMT -5
P&P of Metadate CD from rxlist:
Metadate ER from rxlist:
Pharmacodynamics
Methylphenidate HCl is a central nervous system (CNS) stimulant. The mode of therapeutic action in Attention Deficit Hyperactivity Disorder (ADHD) is not known. Methylphenidate is thought to block the reuptake of norepinephrine and dopamine into the presynaptic neuron and increase the release of these monoamines into the extraneuronal space. Methylphenidate is a racemic mixture comprised of the d-and l-threo enantiomers. The d-threo enantiomer is more pharmacologically active than the l-threo enantiomer.
Pharmacokinetics
The pharmacokinetics of the METADATE CD methylphenidate hydrochloride formulation have been studied in healthy adult volunteers and in children with Attention Deficit Hyperactivity Disorder (ADHD).
Absorption And Distribution
Methylphenidate is readily absorbed. METADATE CD has a plasma/time concentration profile showing two phases of drug release with a sharp, initial slope similar to a methylphenidate immediate-release tablet, and a second rising portion approximately three hours later, followed by a gradual decline. (See Figure 1 below.)
Comparison Of Immediate Release (IR) And METADATE CD Formulations After Repeated Doses Of Methylphenidate HCl In Children With ADHD
METADATE CD was administered as repeated once-daily doses of 20 mg or 40 mg to children aged 7-12 years with ADHD for one week. After a dose of 20 mg, the mean (±SD) early Cmax was 8.6 (±2.2) ng/mL, the later Cmax was 10.9 (±3.9)* ng/mL and AUC0-9h was 63.0 (±16.8) ng•h/mL. The corresponding values after a 40 mg dose were 16.8 (±5.1) ng/mL, 15.1 (±5.8)* ng/mL and 120 (±39.6) ng•h/mL, respectively. The early peak concentrations (median) were reached about 1.5 hours after dose intake, and the second peak concentrations (median) were reached about 4.5 hours after dose intake. The means for Cmax and AUC following a dose of 20 mg were slightly lower than those seen with 10 mg of the immediate-release formulation, dosed at 0 and 4 hours.
*25-30% of the subjects had only one observed peak (Cmax) concentration of methylphenidate.
FIGURE 1 : Comparison of Immediate Release (IR) and METADATE CD Formulations After Repeated Doses of Methylphenidate HCl in Children with ADHD
View Enlarged Table
Dose Proportionality
Following single oral doses of 10-60 mg methylphenidate free base as a solution given to ten healthy male volunteers, Cmax and AUC increased proportionally with increasing doses. After the 60 mg dose, tmax was reached 1.5 hours post-dose, with a mean Cmax of 31.8 ng/mL (range 24.7-40.9 ng/mL).
Following one week of repeated once-daily doses of 20 mg or 40 mg METADATE CD to children aged 7-12 years with ADHD, Cmax and AUC were proportional to the administered dose.
Food Effects
In a study in adult volunteers to investigate the effects of a high-fat meal on the bioavailability of a dose of 40 mg, the presence of food delayed the early peak by approximately 1 hour (range -2 to 5 hours delay). The plasma levels rose rapidly following the food-induced delay in absorption. Overall, a high-fat meal increased the Cmax of METADATE CD by about 30% and AUC by about 17%, on average (see DOSAGE AND ADMINISTRATION).
After a single dose, the bioavailability (Cmax and AUC) of methylphenidate in 26 healthy adults was unaffected by sprinkling the capsule contents on applesauce as compared to the intact capsule. This finding demonstrates that a 20 mg METADATE CD Capsule, when opened and sprinkled on one tablespoon of applesauce, is bioequivalent to the intact capsule.
Metabolism And Excretion
In humans, methylphenidate is metabolized primarily via deesterification to alpha-phenylpiperidine acetic acid (ritalinic acid). The metabolite has little or no pharmacologic activity.
In vitro studies showed that methylphenidate was not metabolized by cytochrome P450 isoenzymes, and did not inhibit cytochrome P450 isoenzymes at clinically observed plasma drug concentrations.
The mean terminal half-life (t½) of methylphenidate following administration of METADATE CD (t½=6.8h) is longer than the mean terminal (t½) following administration of methylphenidate hydrochloride immediate-release tablets (t½=2.9h) and methylphenidate hydrochloride sustained-release tablets (t½=3.4h) in healthy adult volunteers. This suggests that the elimination process observed for METADATE CD is controlled by the release rate of methylphenidate from the extended-release formulation, and that the drug absorption is the rate-limiting process.
Alcohol Effect
An in vitro study was conducted to explore the effect of alcohol on the release characteristics of methylphenidate from the METADATE CD 60 mg capsule dosage form. At an alcohol concentration of 40% there was an increase in the release rate of methylphenidate in the first hour, resulting in 84% of the methylphenidate being released. The results with the 60 mg capsule are considered to be representative of the other available capsule strengths. Patients should be advised to avoid alcohol while taking METADATE CD.
Methylphenidate HCl is a central nervous system (CNS) stimulant. The mode of therapeutic action in Attention Deficit Hyperactivity Disorder (ADHD) is not known. Methylphenidate is thought to block the reuptake of norepinephrine and dopamine into the presynaptic neuron and increase the release of these monoamines into the extraneuronal space. Methylphenidate is a racemic mixture comprised of the d-and l-threo enantiomers. The d-threo enantiomer is more pharmacologically active than the l-threo enantiomer.
Pharmacokinetics
The pharmacokinetics of the METADATE CD methylphenidate hydrochloride formulation have been studied in healthy adult volunteers and in children with Attention Deficit Hyperactivity Disorder (ADHD).
Absorption And Distribution
Methylphenidate is readily absorbed. METADATE CD has a plasma/time concentration profile showing two phases of drug release with a sharp, initial slope similar to a methylphenidate immediate-release tablet, and a second rising portion approximately three hours later, followed by a gradual decline. (See Figure 1 below.)
Comparison Of Immediate Release (IR) And METADATE CD Formulations After Repeated Doses Of Methylphenidate HCl In Children With ADHD
METADATE CD was administered as repeated once-daily doses of 20 mg or 40 mg to children aged 7-12 years with ADHD for one week. After a dose of 20 mg, the mean (±SD) early Cmax was 8.6 (±2.2) ng/mL, the later Cmax was 10.9 (±3.9)* ng/mL and AUC0-9h was 63.0 (±16.8) ng•h/mL. The corresponding values after a 40 mg dose were 16.8 (±5.1) ng/mL, 15.1 (±5.8)* ng/mL and 120 (±39.6) ng•h/mL, respectively. The early peak concentrations (median) were reached about 1.5 hours after dose intake, and the second peak concentrations (median) were reached about 4.5 hours after dose intake. The means for Cmax and AUC following a dose of 20 mg were slightly lower than those seen with 10 mg of the immediate-release formulation, dosed at 0 and 4 hours.
*25-30% of the subjects had only one observed peak (Cmax) concentration of methylphenidate.
FIGURE 1 : Comparison of Immediate Release (IR) and METADATE CD Formulations After Repeated Doses of Methylphenidate HCl in Children with ADHD
View Enlarged Table
Dose Proportionality
Following single oral doses of 10-60 mg methylphenidate free base as a solution given to ten healthy male volunteers, Cmax and AUC increased proportionally with increasing doses. After the 60 mg dose, tmax was reached 1.5 hours post-dose, with a mean Cmax of 31.8 ng/mL (range 24.7-40.9 ng/mL).
Following one week of repeated once-daily doses of 20 mg or 40 mg METADATE CD to children aged 7-12 years with ADHD, Cmax and AUC were proportional to the administered dose.
Food Effects
In a study in adult volunteers to investigate the effects of a high-fat meal on the bioavailability of a dose of 40 mg, the presence of food delayed the early peak by approximately 1 hour (range -2 to 5 hours delay). The plasma levels rose rapidly following the food-induced delay in absorption. Overall, a high-fat meal increased the Cmax of METADATE CD by about 30% and AUC by about 17%, on average (see DOSAGE AND ADMINISTRATION).
After a single dose, the bioavailability (Cmax and AUC) of methylphenidate in 26 healthy adults was unaffected by sprinkling the capsule contents on applesauce as compared to the intact capsule. This finding demonstrates that a 20 mg METADATE CD Capsule, when opened and sprinkled on one tablespoon of applesauce, is bioequivalent to the intact capsule.
Metabolism And Excretion
In humans, methylphenidate is metabolized primarily via deesterification to alpha-phenylpiperidine acetic acid (ritalinic acid). The metabolite has little or no pharmacologic activity.
In vitro studies showed that methylphenidate was not metabolized by cytochrome P450 isoenzymes, and did not inhibit cytochrome P450 isoenzymes at clinically observed plasma drug concentrations.
The mean terminal half-life (t½) of methylphenidate following administration of METADATE CD (t½=6.8h) is longer than the mean terminal (t½) following administration of methylphenidate hydrochloride immediate-release tablets (t½=2.9h) and methylphenidate hydrochloride sustained-release tablets (t½=3.4h) in healthy adult volunteers. This suggests that the elimination process observed for METADATE CD is controlled by the release rate of methylphenidate from the extended-release formulation, and that the drug absorption is the rate-limiting process.
Alcohol Effect
An in vitro study was conducted to explore the effect of alcohol on the release characteristics of methylphenidate from the METADATE CD 60 mg capsule dosage form. At an alcohol concentration of 40% there was an increase in the release rate of methylphenidate in the first hour, resulting in 84% of the methylphenidate being released. The results with the 60 mg capsule are considered to be representative of the other available capsule strengths. Patients should be advised to avoid alcohol while taking METADATE CD.
METADATE ER (methylphenidate hydrochloride tablet) is a mild central nervous system stimulant.
The mode of action in man is not completely understood, but methylphenidate presumably activates the brain stem arousal system and cortex to produce its stimulant effect.
There is neither specific evidence which clearly establishes the mechanism whereby methylphenidate produces its mental and behavioral effects in children, nor conclusive evidence regarding how these effects relate to the condition of the central nervous system.
METADATE ER (methylphenidate hydrochloride tablet) in extended-release tablets is more slowly but as extensively absorbed as in the regular tablets. Bioavailability of METADATE 20 mg Extended-Release Tablets was compared to a sustained-release reference product and an immediate-release product. The extent of absorption for the three products was similar, and the rate of absorption of the two sustained-release products was not statistically different.
In another reported study with a brand of Methylphenidate HCl sustained-release, the time to peak rate in children was reported as 4.7 hours (1.3 - 8.2 hours) for the sustained-release tablet dosage form and 1.9 hours (0.3 - 4.4 hours) for immediate release tablets. An average of 67% of a sustained-release tablet dosage form was excreted in children compared to 86% in adults.
Based on rate of bioavailability (AUC0#∞, Tmax, and Cmax), no significant statistical difference was found following single dose administration, in fasting and fed adults, of two METADATE 10 mg Extended-Release Tablets, or one methylphenidate hydrochloride, USP sustained-release 20 mg tablet. The administration of the extended-release methylphenidate HCl, USP, tablets with food, resulted in a greater Cmax and AUC0#∞ than when administered in a fasting condition.
Pharmacokinetic and statistical analyses for a multiple dose study demonstrated that 3 times daily administration of two METADATE 10 mg Extended-Release Tablets met the requirements for bioequivalence to one methylphenidate hydrochloride, USP sustainedrelease 20 mg tablet when administered every eight hours. Pharmacokinetic parameters (i.e., AUC0#∞, Tmax, Cmax, Cmin, and Cav) demonstrated achievement of steady state following 3 times daily administration of two METADATE 10 mg Extended-Release Tablets was confirmed.
In a clinical study involving adult subjects who received Extended-release (ER) tablets, plasma concentrations of methylphenidate hydrochloride's major metabolite appeared to be greater in females than in males. No gender differences were observed for methylphenidate hydrochloride's plasma concentration in the same subjects.
The mode of action in man is not completely understood, but methylphenidate presumably activates the brain stem arousal system and cortex to produce its stimulant effect.
There is neither specific evidence which clearly establishes the mechanism whereby methylphenidate produces its mental and behavioral effects in children, nor conclusive evidence regarding how these effects relate to the condition of the central nervous system.
METADATE ER (methylphenidate hydrochloride tablet) in extended-release tablets is more slowly but as extensively absorbed as in the regular tablets. Bioavailability of METADATE 20 mg Extended-Release Tablets was compared to a sustained-release reference product and an immediate-release product. The extent of absorption for the three products was similar, and the rate of absorption of the two sustained-release products was not statistically different.
In another reported study with a brand of Methylphenidate HCl sustained-release, the time to peak rate in children was reported as 4.7 hours (1.3 - 8.2 hours) for the sustained-release tablet dosage form and 1.9 hours (0.3 - 4.4 hours) for immediate release tablets. An average of 67% of a sustained-release tablet dosage form was excreted in children compared to 86% in adults.
Based on rate of bioavailability (AUC0#∞, Tmax, and Cmax), no significant statistical difference was found following single dose administration, in fasting and fed adults, of two METADATE 10 mg Extended-Release Tablets, or one methylphenidate hydrochloride, USP sustained-release 20 mg tablet. The administration of the extended-release methylphenidate HCl, USP, tablets with food, resulted in a greater Cmax and AUC0#∞ than when administered in a fasting condition.
Pharmacokinetic and statistical analyses for a multiple dose study demonstrated that 3 times daily administration of two METADATE 10 mg Extended-Release Tablets met the requirements for bioequivalence to one methylphenidate hydrochloride, USP sustainedrelease 20 mg tablet when administered every eight hours. Pharmacokinetic parameters (i.e., AUC0#∞, Tmax, Cmax, Cmin, and Cav) demonstrated achievement of steady state following 3 times daily administration of two METADATE 10 mg Extended-Release Tablets was confirmed.
In a clinical study involving adult subjects who received Extended-release (ER) tablets, plasma concentrations of methylphenidate hydrochloride's major metabolite appeared to be greater in females than in males. No gender differences were observed for methylphenidate hydrochloride's plasma concentration in the same subjects.