Serum morphine concentrations after buccal and intramuscular morphine administration

Area of Science:

• Pharmacology
• Clinical Pharmacy
• Drug Delivery Systems

Background:

• Morphine is a potent opioid analgesic used for pain management.
• Buccal drug delivery offers an alternative route for systemic administration.
• Understanding morphine pharmacokinetics via buccal administration is crucial for optimizing pain control.

Purpose of the Study:

• To compare serum morphine concentrations following buccal tablet administration versus intramuscular injection.
• To evaluate the pharmacokinetic profile of buccal morphine, including peak concentration and time to peak.
• To assess the interindividual variability in serum morphine levels after buccal administration.

Main Methods:

• Serum morphine concentrations were measured using high-performance liquid chromatography (HPLC).
• Buccal morphine (25mg) was given to 11 healthy volunteers; intramuscular morphine (10mg) was given to 5 surgical patients.
• Blood samples were collected up to 8 hours post-administration for analysis.

Main Results:

• Mean maximum serum morphine concentrations were 8 times lower with buccal administration compared to intramuscular injection.
• The time to reach mean maximum morphine concentration was delayed by approximately 4 hours with the buccal route.
• Significant interindividual variability in morphine concentrations was observed with the buccal tablet, linked to tablet retention time.

Conclusions:

• Buccal morphine administration leads to lower and delayed peak serum concentrations compared to intramuscular injection.
• The buccal route exhibits considerable interindividual variability, potentially affecting therapeutic efficacy.
• Further research is needed to optimize buccal morphine formulations for predictable pain relief.