<p>Diclofenac has a total volume of distribution of 5-10 L or 0.1-0.2 L/kg.<sup class="text-reference-group"><a class="reference-popover-link" data-content="Davies NM, Anderson KE: Clinical pharmacokinetics of diclofenac. Therapeutic insights and pitfalls. Clin Pharmacokinet. 1997 Sep;33(3):184-213. doi: 10.2165/00003088-199733030-00003. (PubMed ID 9314611)" href="#reference-A178633">7</a></sup> The volume of the central compartment is 0.04 L/kg.<sup class="text-reference-group"><a class="reference-popover-link" data-content="Todd PA, Sorkin EM: Diclofenac sodium. A reappraisal of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy. Drugs. 1988 Mar;35(3):244-85. doi: 10.2165/00003495-198835030-00004. (PubMed ID 3286213)" href="#reference-A180694">8</a></sup> Diclofenac distributes to the synovial fluid reaching peak concentration 2-4h after administration.<sup class="text-reference-group"><a class="reference-popover-link" data-content="Davies NM, Anderson KE: Clinical pharmacokinetics of diclofenac. Therapeutic insights and pitfalls. Clin Pharmacokinet. 1997 Sep;33(3):184-213. doi: 10.2165/00003088-199733030-00003. (PubMed ID 9314611)" href="#reference-A178633">7</a></sup> There is limited crossing of the blood brain barrier and cerebrospinal fluid concentrations only reach 8.22% of plasma concentrations. Doses of 50 mg delivered via intramuscular injection produced no detectable diclofenac concentrations in breast milk, however metabolite concentrations were not investigated. Diclofenac has been shown to cross the placenta in mice and rats but human data is unavailable.<sup class="text-reference-group"><a class="reference-popover-link" data-content="Todd PA, Sorkin EM: Diclofenac sodium. A reappraisal of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy. Drugs. 1988 Mar;35(3):244-85. doi: 10.2165/00003495-198835030-00004. (PubMed ID 3286213)" href="#reference-A180694">8</a></sup></p>