Hemp Therapies Wiki / Liposomal Delivery Systems

Liposomal Technology in Approved Pharmaceuticals

Liposomal delivery has an established regulatory history in pharmaceutical medicine, with multiple FDA-approved drugs built on the technology.

Doxil, the First Approved Liposomal Drug

The U.S. Food and Drug Administration approved Doxil, a pegylated liposomal formulation of the chemotherapy drug doxorubicin, in November 1995, initially for treating AIDS-related Kaposi’s sarcoma. Doxil’s liposomes are described in FDA labeling as “STEALTH” liposomes, meaning the particle surface is modified with methoxypolyethylene glycol (a process called pegylation) intended to reduce detection and clearance by the body’s mononuclear phagocyte system and extend circulation time in the bloodstream. Doxil’s liposome shell has a reported circulation half-life of approximately 55 hours in humans, with at least 90% of the doxorubicin reported to remain liposome-encapsulated while circulating.

Other Approved and Studied Liposomal Drugs

Other liposomal drug products with FDA approval or clinical use include DaunoXome (daunorubicin), DepoCyt (cytarabine), Marqibo (vincristine), Onivyde (irinotecan), Vyxeos (a cytarabine/daunorubicin combination), and AmBisome (amphotericin B) — an antifungal formulation in which amphotericin B is encapsulated within a liposome shell rather than delivered as a free compound. Exparel is an injectable, liposomal formulation of the local anesthetic bupivacaine, administered at a surgical site as a single-dose suspension at a fixed concentration of 13.3 mg/mL. Exparel’s formulation encapsulates bupivacaine within small lipid-based particles designed for extended-duration release, and prescribing guidance, referred to as the “Exparel 50 rule,” limits how much non-liposomal bupivacaine can be combined with it during the same procedure. Liposome-encapsulated amikacin has been studied in past clinical trials as an inhaled antibiotic delivery format for cystic fibrosis patients with Pseudomonas lung infections.

Lipid Nanoparticle mRNA Vaccines

Lipid nanoparticle-based mRNA vaccines, including the Pfizer-BioNTech and Moderna COVID-19 vaccines, use a lipid-based particle composed of cationic lipids, PEGylated lipids, phospholipids, and cholesterol — sharing compositional overlap with liposome technology while relying on a different internal particle structure suited to carrying nucleic acid material.

Scale of Clinical Use

The National Cancer Institute’s Drug Dictionary maintains individual reference entries for multiple liposomal drug formulations, including liposomal NDDP, liposomal curcumin, liposomal amphotericin B, and pegylated liposomal doxorubicin hydrochloride. A count reported in December 2021 identified more than 500 liposomal drug formulations in active clinical trials across Phase I, II, and III stages.

Summary

Liposomal delivery has three decades of pharmaceutical regulatory history, beginning with Doxil’s 1995 approval and extending to a range of FDA-approved cancer, antifungal, and anesthetic drugs, plus a structurally related lipid nanoparticle format used in mRNA vaccines.