Philcort-16 Mechanism of Action

Pharmacotherapeutic group: Corticosteroid.
Pharmacology: Mechanism of Action: Methylprednisolone is a potent anti-inflammatory steroid. It has greater anti-inflammatory potency than prednisolone, even less tendency than prednisolone to induce sodium and water retention. The relative potency of methylprednisolone to hydrocortisone is at least four to one.
Pharmacokinetics: Methylprednisolone pharmacokinetics is linear, independent of route of administration.
Absorption: Methylprednisolone is rapidly absorbed and the maximum plasma methylprednisolone concentration is achieved around 1.5 to 2.3 hours across doses following oral administration in normal healthy adults. The absolute bioavailability of methylprednisolone in normal healthy subjects is generally high (82% to 89%) following oral administration. The mean oral time of peak concentration is 1.1-2.2 hours.
Distribution: Methylprednisolone is widely distributed throughout the body and is described by a two-compartment model. The mean volume of distribution reported in 34 adults volunteers ranged from 41 to 61.5 L. Methylprednisolone is widely distributed into the tissues, crosses the blood-brain barrier, the placental barrier, and is secreted in breast milk. Its apparent volume of distribution is approximately 1.4 L/kg. The plasma protein binding of methylprednisolone in humans is approximately 77%.
Methylprednisolone Tablets readily crosses the blood-brain barrier into the central nervous system with peak CSF levels being 5-6% of the corresponding plasma levels. Methylprednisolone peak CSF levels occurred within five minutes to one hour after IV administration of a 500 mg dose to patients with lupus cerebritis.
Metabolism: In humans, methylprednisolone is metabolised in the liver to inactive metabolites, the major ones 20 α-hydroxymethylprednisolone and 20 β-hydroxymethylprednisolone. Metabolism in the liver occurs primarily via the CYP3A4 enzyme. For a list of drug interactions based on CYP3A4-mediated metabolism.
Methylprednisolone, like many CYP3A4 substrates, may also be a substrate for the ATP-binding cassette (ABC) transport protein p-glycoprotein, influencing tissue distribution and interactions with other medicines.
Elimination: The mean elimination half-life for total methylprednisolone is in the range of 1.8 to 5.2 hours. Total clearance is approximately 5 to 6 mL/min/kg.
Following IV administration of radiolabelled 6-methylprednisolone to six cancer patients, 75% of total reactivity was recovered in the urine after 96 hours and 9% in the faeces after five days. Twenty percent of the total dose was excreted in the bile, but the time course was not cited.