Ultra-Micronized vs Liposomal PEA 600 mg: A Crossover PK Study in Healthy Subjects

**Detailed Description**

Palmitoylethanolamide (PEA) is an endogenous lipid mediator belonging to the N-acylethanolamine family, extensively studied for its analgesic, immunomodulatory, antimicrobial, and anti-inflammatory properties. It is currently used as a nutraceutical for its antinociceptive, neuroprotective, and immunomodulatory effects, particularly in supporting brain and joint health and in mitigating inflammatory processes. Despite this significant potential, the clinical utility of PEA is limited by its poor water solubility, extensive gastrointestinal metabolism, and consequently low oral bioavailability. Over the years, several technological strategies have been explored to improve the pharmacokinetic profile of PEA, including particle-size reduction techniques such as micronization and ultra-micronization, as well as the use of lipid-based carriers such as liposomal delivery systems.

This single-center, open-label, randomized (systematic alternate allocation), two-treatment, two-period, single-dose crossover study is designed to compare the oral absorption of a single 600 mg dose of PEA administered in two different technological formulations: an ultra-micronized formulation (Normast 600, tablet) and a liposomal formulation (AliaMed, sachet), in order to evaluate the impact of formulation technology on the nutraceutical utilization of the molecule.

A total of 6 healthy adult subjects will be enrolled at the Crabion S.r.l. research center (Corciano, Perugia, Italy) among individuals presenting for routine laboratory testing who meet the eligibility criteria and provide written informed consent.

Participants will be allocated to one of two sequence groups using non-random, systematic alternate allocation: Group 1 (n=3) will receive Treatment A (ultra-micronized PEA, Normast 600) in Period 1 followed, after washout, by Treatment B (liposomal PEA, AliaMed) in Period 2; Group 2 (n=3) will receive Treatment B in Period 1 followed by Treatment A in Period 2. On Day 1 of each period, after a fasting baseline blood draw (T0), subjects will take a single oral 600 mg dose of PEA according to group assignment; breakfast will be permitted immediately after dosing. Venous blood samples (~3 mL per draw) will be collected at 0.5, 1, 2, 4, and 24 hours post-dose. Subjects will remain at the research center for approximately 4 hours (through the 4-hour draw) and will return the following morning for the 24-hour sample. A 7-day washout period separates the two treatment periods, after which the crossover occurs and the alternate formulation is administered following the same sampling schedule.

At each visit, clinical examination and blood collection are performed for: complete blood count (T0 and 24h only), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) (all time points), plasma PEA quantification (all time points), and plasma 2-arachidonoylglycerol (2-AG) quantification (all time points). Blood is collected using a 22G two-way cannula needle into NaEDTA-anticoagulated tubes (hematology, PEA, 2-AG, ESR) and into dry tubes with separator gel (CRP). PEA and 2-AG are quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) following protein precipitation, extraction, and purification with appropriate organic solvents; absolute quantification is based on a multi-level calibration curve prepared in matrix, with linearity, accuracy, and precision verified according to international bioanalytical guidelines.

Sample size was calculated using G*Power 3.1.9.7 based on the primary endpoint (AUC₁ ≠ AUC₂), using a paired-samples t-test consistent with the crossover design, an effect size of 1.327 derived from AUC data of a reference pharmacokinetic comparison study of two PEA formulations, a type I error probability (α) of 0.05, and a statistical power (1-β) of 80%, yielding a total sample size of 6 subjects.

The overall study duration is 24 days, comprising: subject enrollment (1 day); the study phase itself, including both treatment periods and washout (9 days); execution of chemical/biochemical analyses at the CRABION S.r.l. laboratory (7 days); and statistical analysis and data processing (7 days). Blood samples will not be retained beyond the end of the study, as they will be fully utilized for study-related analyses.

The study will be conducted in accordance with the ethical principles of the Declaration of Helsinki, Good Clinical Practice (GCP) guidelines, and applicable clinical research regulations. The main procedural risk is associated with venipuncture and may occasionally include mild discomfort or transient pain, minor hematoma at the puncture site, vasovagal reaction (spontaneously and rapidly resolving), or, in very rare cases, local inflammation or infection. These risks are considered minimal and proportionate to the scientific objective of the study; appropriate monitoring is in place to ensure immediate intervention if such events occur.

Inclusion criteria

• Aged 18-70 years
• BMI 18-30 kg/m²
• Healthy participants
• Written informed consent

Exclusion criteria

• Use of PEA-based supplements in the preceding 2 weeks.
• Significant liver, kidney, gastrointestinal or metabolic conditions.
• Known allergy or intolerance to PEA or excipients.
• Pregnancy or breastfeeding