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Palmitoylethanolamide (PEA, N -hexadecanoylethanolamide) is an endogenous compound belonging to the family of N -acylethanolamines. PEA has anti-inflammatory and analgesic properties and is very well tolerated in humans. In the present article, the basal pharmacology of PEA is reviewed. In terms of its pharmacokinetic properties, most work has been undertaken upon designing formulations for its absorption and upon characterising the enzymes involved in its metabolism, but little is known about its bioavailability, tissue distribution, and excretion pathways. PEA exerts most of its biological effects in the body secondary to the activation of peroxisome proliferator-activated receptor-α (PPAR-α), but PPAR-α-independent pathways involving other receptors (Transient Receptor Potential Vanilloid 1 (TRPV1), GPR55) have also been identified. Given the potential clinical utility of PEA, not least for the treatment of pain where there is a clear need for new well-tolerated drugs, we conclude that the gaps in our knowledge, in particular those relating to the pharmacokinetic properties of the compound, need to be filled.

Ketorolac tromethamine is a racemic, non-steroidal, anti-inflammatory drug (NSAID). An intra-nasal (IN) formulation, SPRIX(®), is approved for the treatment of short term (up to 5 days) acute moderate to moderately severe pain. The primary objective of this study was to determine whether (99m)Tc-diethylenetriaminepenta acetic acid (DTPA) radiolabelled ketorolac tromethamine formulation (31.5 mg) was deposited in the lungs of healthy subjects (4 men and 9 women) following nasal inhalation of different intensities (gentle or vigorous sniff) and under different postural conditions (upright or semi-supine). The secondary objectives were to determine the deposition pattern of radiolabelled ketorolac solution in the nasal cavity and the clearance of the radiolabel over a 6h period post-administration. The nasal spray pump delivery device used showed a droplet size distribution with a volume mean diameter (VMD) of 50 μm and approximately 85% of the aerosol mass contained in droplets >10 μm diameter. The fraction of the dose recorded from the lung regions averaged <0.5%, and was considered to represent scattered radiation rather than true pulmonary deposition. This fraction was not affected by posture or by inhalation manoeuvre. The majority of the radiolabelled intranasal dose was deposited in the nasal cavity. The visual spread patterns within the nasal cavity were most uniform following administration in the upright position regardless of inhalation manoeuvre. Clearance from the nasal cavity was initially very rapid, with only 16-30% of the dose remaining after 10 min and 6-14% after 6 h. Retention was greatest following gentle inhalation., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Bacillus megaterium contains a soluble cytochrome P450 termed BM-3, which is highly inducible by barbiturates, peroxisome proliferators, and nonsteroidal antiinflammatory drugs. In rats and mice, the chronic administration of peroxisome proliferators induces a sustained oxidative stress in hepatic tissue and may be responsible for the nongenotoxic carcinogenesis observed with prolonged treatment. Here it is shown that ibuprofen induces a variety of enzymes associated with the oxidative stress response in Bacillus, including catalase, glucose-6-phosphate-dehydrogenase, and aldehyde reductase in a dose-related manner. Furthermore, evidence is presented to show that the expression of cytochrome P450 in Bacillus is associated with a marked depletion in cellular glutathione levels and that it renders these cells considerably more sensitive to oxidant insult. Finally, this work reports that a variety of structurally diverse antioxidants such as ascorbic acid, reduced glutathione, alpha-tocopherol acetate and the artificial antioxidant, butylated hydroxyanisole, all dramatically attenuate the expression of the cytochrome P450BM-3 gene and its repressor, Bm3R1, following ibuprofen treatment. These observations provide the first evidence that the expression of cytochrome P450 genes can lead to increased oxidant sensitivity but can be strongly modulated by dietary and artificial antioxidants, as well as antioxidant enzymes. The important implications of this phenomenon are also discussed.