A subcutaneous injection of liposomal synthetic CBD provided sustained blood levels and pain relief in dogs with osteoarthritis—bypassing the poor oral absorption that limits current CBD products.
Veterinarians treating canine arthritis, pharmaceutical scientists developing CBD formulations, and researchers interested in drug delivery innovation.
What the researchers found
Oral CBD has a fundamental problem: most of it gets destroyed by the liver before reaching the bloodstream (first-pass metabolism). This team developed a liposomal CBD formulation—synthetic CBD encapsulated in tiny lipid spheres—designed to be injected subcutaneously, completely bypassing the digestive system.
Eight dogs with radiographically confirmed osteoarthritis each received both the liposomal CBD injection (7 mg/kg) and a placebo injection in a randomized, blinded, crossover design. The 4-week interval between injections allowed washout.
The pharmacokinetic results were striking: the subcutaneous injection provided sustained CBD blood levels that oral formulations can't match. The slow-release properties of the liposomes meant a single injection maintained CBD exposure over an extended period.
Efficacy was assessed through activity monitoring and clinical assessment, building on a pilot study from the same group that had already shown analgesia in arthritic dogs. The synthetic CBD (rather than plant-derived) ensures consistent purity and avoids THC contamination.
While this is a veterinary study, the bioavailability challenge it addresses is identical in humans. The same liposomal technology could potentially be adapted for human use, where oral CBD's poor absorption similarly limits therapeutic potential.
Why it matters
Poor oral bioavailability is the single biggest limitation of current CBD therapeutics—for both animals and humans. If injectable liposomal CBD can provide sustained therapeutic levels from a single injection, it could transform how CBD is used for chronic pain. The veterinary application also matters directly: many dog owners already give their pets oral CBD for arthritis with questionable absorption.
The numbers in context
8 dogs with confirmed OA. 7 mg/kg subcutaneous L-sCBD (50 mg/mL). Crossover with 4-week washout. Sustained CBD blood levels from single injection. Safety monitored via CBC and serum chemistry for 4 weeks.
How the study worked
Randomized, blinded, placebo-controlled, crossover trial in 8 client-owned dogs (4M, 4F; median age 8.5 years; median weight 34.9 kg) with radiographically confirmed osteoarthritis. Two subcutaneous injections 4 weeks apart: 7 mg/kg liposomal synthetic CBD (L-sCBD, 50 mg/mL) and empty liposomes (placebo). Blood sampled for CBD and metabolites, CBC, and serum chemistry up to 4 weeks post-injection.
Who was studied
N=8 dogs (4 males, 4 females; aged 4.5-12.5 years; weight 22.7-42.7 kg)
What this study cannot tell us
Very small sample (8 dogs). Veterinary data—dog pharmacokinetics and OA pathophysiology differ from humans. Subcutaneous injection isn't as convenient as oral dosing for chronic conditions. The crossover design is efficient but 4-week washout may be insufficient if liposomal CBD has very long tissue half-life. No comparison to oral CBD in this study. Client-owned dogs continued their routine analgesics, which could mask effects.
How to read the evidence
Small randomized crossover trial in dogs—strong design for a veterinary pilot but requires larger studies and human translation.
When this study was published
Published in 2025, building on the team's prior pilot data on liposomal CBD in dogs.
The bigger picture
This addresses the same bioavailability problem as RTHC-00179 (DehydraTECH oral formulation) and the nanotechnology approaches reviewed in RTHC-00184—but from a completely different angle: bypassing oral absorption entirely. RTHC-00182's null result for oral CBD in knee osteoarthritis raises the question of whether the negative finding was due to CBD not working for OA or due to insufficient drug reaching the joints. An injectable formulation could help answer that question.
Replication
Not stated in abstract.
Funding
Not reported in abstract.
Conflicts of interest
Not reported in abstract.
Questions still open
- Would liposomal injectable CBD work in human osteoarthritis where oral CBD failed? How often would injections need to be repeated for chronic conditions? Is the convenience trade-off (injection vs. daily oral) acceptable to patients?
Read the original research
Efficacy, pharmacokinetics and safety of liposomal synthetic cannabidiol injected subcutaneously in dogs: a randomized, blinded, placebo-controlled, crossover clinical trial.
Frontiers in veterinary science, 12, 1746266
Frontiers in Veterinary Science is a reputable journal focused on animal health and veterinary research.
Citation
Shilo-Benjamini, Yael; Milgram, Joshua; Lavy, Eran; Quint, Maxim; Barasch, Dinorah; Cern, Ahuva; Barenholz, Yechezkel. (2025). Efficacy, pharmacokinetics and safety of liposomal synthetic cannabidiol injected subcutaneously in dogs: a randomized, blinded, placebo-controlled, crossover clinical trial.. Frontiers in veterinary science, 12, 1746266. https://doi.org/10.3389/fvets.2025.1746266
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