Electrospun Nanofibre System Shields Mitragynine From Stomach Acid, Enabling Targeted Intestinal Delivery

Why it matters

Mitragynine's poor oral bioavailability — as low as 3% — has blocked its development as a pharmaceutical drug. A new drug delivery approach may change that, opening a path toward standardized, dose-controlled kratom-based therapeutics for pain and opioid withdrawal.

The big picture

Mitragynine degrades rapidly in stomach acid, which is why traditional kratom consumption relies on raw leaves or teas that bypass some of this problem. As researchers push to develop purified mitragynine as a regulated pharmaceutical — including an ongoing NIH Phase 1 trial — solving the bioavailability problem is essential. Electrospinning, a technique that creates drug-loaded nanofibres using electrostatic force, has successfully improved delivery of many poorly soluble drugs.

Key findings

• Eudragit L100 fibres protected mitragynine from gastric degradation, releasing only 30% in simulated stomach acid while achieving 128% full release in intestinal fluid
• Eudragit RLPO (time-controlled) fibres released all drug in gastric conditions — unsuitable for targeted intestinal delivery
• Fibre diameters ranged from 331–573 nm, smaller than drug-free fibres, indicating successful drug incorporation
• FTIR analysis confirmed strong polymer-drug interactions protecting the alkaloid structure
• Authors conclude L100 electrospun fibres are a promising platform warranting further in vivo investigation

What they say

The researchers stated: "L100 electrospun fibres represent a promising platform for intestinal delivery of mitragynine and warrant further in vivo investigation." The study, funded by Malaysia's Ministry of Higher Education, is the first to report successful oral delivery of mitragynine via this protection mechanism.

Bottom line

pH-responsive Eudragit L100 nanofibres can protect mitragynine from gastric degradation and deliver it intact to the intestine — a key technical milestone for pharmaceutical development of kratom-derived medicines.