Modes of Association of Indometacin with Human Polymorphonuclear Leucocytes

Abstract

The basic transport properties of indometacin (INDO) were investigated in human blood polymorphonuclear leucocytes (PMNs) of healthy volunteers. The silicone oil cushion centrifugation method was used as ligand-binding assay for both the measurements of the cellular association of INDO and the intracellular volume. This assay enabled us to calculate the intracellular INDO concentrations. A considerable amount of INDO accumulates in the PMNs to cause cell/medium ratios between 20 and 90. At low INDO levels (1–10 nmol/l) the cell/medium ratio appeared to be higher than at high INDO levels (>2 μmol/l). This finding suggests that the cell accumulation of INDO comprises saturable binding and/or transport components. Scatchard analysis of the association isotherm of INDO after incubation for 60 min at 37 °C reveals apparent K_D values of 3.7 μmol/l (low affinity) and 1.2 nmol/l (high affinity). The number of high-affinity association sites (60 fmol/3 × 106 PMNs) was 1,000–2,000 times lower than the number of low-affinity association sites (103 pmol/3 × 10⁶ PMNs). INDO cell association is suggested to be a net result of diffusive and mediated influx and efflux mechanisms, and of binding to (plasma) membranes. The capacity of the PMN to accumulate INDO is enhanced upon (1) establishment of an inward gradient of [H⁺], and (2) activation of the Na⁺-H⁺ antiport by chemotactic peptide. The possible mechanisms of incorporation of INDO in the PMN are discussed in the scope of the proposed PMN-related anti-inflammatory action of INDO.

S(+)-Flurbiprofen Shows Potent PGE2 Inhibitory Activity in Inflammatory Cells, Superior Cell Transport Activity and Skin Permeability

“…There are only a few reports on the binding affinities of other NSAIDs to PMNs. Raghoebar reported that indomethacin was rapidly taken up by the cells, reaching a steady state after 30 min [12], which is consistent with the rapid cell binding of SFP observed in our study. However, it remained unclear in our binding study as to whether the SFP was incorporated into the cells or not.…”

“…The whole cell was kept at 37˚C and stirred using a magnetic stirrer. An aliquot of the receiver solution was collected as the sample at determined times (4,6,8,10,12 and 24 h). The concentrations of SFP and RFP in the samples were determined by HPLC.…”

Hydroxychloroquine blood levels predicts flare in childhood-onset lupus nephritis

“…Higher leukocytes and lymphocytes counts were also associated with higher HCQ blood levels in our cSLE patients. These findings had already been reported in the adult population, possibly indicating the role of these immune cells as targets for drug accumulation and transport to inflamed tissues 24,25 .…”

Avaliação dos níveis sanguíneos de hidroxicloroquina em pacientes com doença de Sjögren: adesão à medicação e correlações clínicas

“…Estudos em animais e humanos demonstraram ainda que o estado de equilíbrio da concentração de HCQ nos diferentes tecidos e no plasma é atingido após três meses de tratamento (Browning, 2014). Além disso, a aplicação de critérios de exclusão rigorosos foi importante para evitar fatores de confusão devido a interações medicamentosas (McElnay et al, 1985;Munster et al, 2002;Browning, 2014;Melles & Marmor, 2014;Jallouli et al, 2015;Baburaj et al, 2021), bem como infecções atuais, insuficiências hepática, cardíaca e renal grave (Raghoebar et al, 1986;Schrezenmeier & Dörner, 2020).…”

“…insuficiências hepática e cardíaca (Raghoebar et al, 1986;Schrezenmeier & Dörner, 2020); diálise, insuficiência renal crônica grave (creatinina sérica ≥ 3 mg/dL) (AbuRahma et al, 2014;Schrezenmeier & Dörner, 2020); gestação; e recusa em participar do estudo. A adesão ao tratamento foi avaliada por meio dos dados eletrônicos de refil de farmácia (RF) disponíveis no sistema de dispensação de medicamentos da farmácia institucional.…”