Phospholipid-Based Delivery System Optimizes the Solubility and Systemic Exposure of Palmitoylethanolamide and Supports Clinical Benefits in Chronic Neuropathic Low Back Pain

Background: Chronic neuropathic low back pain (LBP) is a prevalent health condition and difficult to treat. Conventional therapies often provide limited relief and raise safety concerns. Supplemental palmitoylethanolamide (PEA), an endogenous fatty acid amide with analgesic and anti-inflammatory properties, has shown benefits in neuropathic pain, but its application as a supportive strategy has been limited by poor oral bioavailability. Objectives: This study aimed to investigate a phospholipid-based palmitoylethanolamide formulation (PEA-PL, Cronilief™), developed using Phytosome™ delivery technology, with respect to solubility optimization, systemic exposure, and associated clinical effects in individuals with chronic neuropathic LBP. Methods: PEA-PL solubility was assessed in fasted-state simulated intestinal fluid and compared with unformulated PEA. Plasma PEA concentrations were evaluated in healthy volunteers after 2 weeks of supplementation with unformulated PEA (300 mg/day) or PEA-PL (300 or 600 mg/day). Clinical efficacy was assessed in a double-blind, placebo-controlled randomized, trial in which 120 adults with neuropathic LBP received PEA-PL 600 → 300 mg (n = 40), PEA-PL 450 mg (n = 40), or placebo (n = 40), daily for 8 weeks in addition to Standard of Care. Primary outcomes were effects on neuropathic pain (Douleur Neuropathique 4, DN4) and its intensity (Numeric Pain Rating Scale, NPRS). Secondary outcomes included effect on functional disability (Oswestry Disability Index, ODI), sleep quality (Pittsburgh Sleep Quality Index, PSQI), quality of life (QoL) (SF-12), and concomitant analgesic use. Safety was monitored throughout the 8-week supplementation period. Results: PEA-PL increased PEA solubility approximately eight-fold and resulted in higher plasma PEA concentrations than unformulated PEA. Both PEA-PL regimens significantly improved pain, functional disability, sleep, and QoL outcomes versus placebo (all p < 0.0001), with greater effects for the 600 → 300 mg regimen. Analgesic discontinuation occurred more frequently in PEA-PL groups (65–70%). Supplementation was well tolerated. Conclusions: A phospholipid-based (Phytosome™) PEA formulation (Cronilief™) was developed and associated with optimized systemic exposure and clinically meaningful reductions in pain severity and functional disability in individuals with chronic neuropathic LBP.