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Publication
A molecular biophysical approach to diclofenac topical gastrointestinal damage
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| 3.51 MB | Adobe PDF |
Advisor(s)
Abstract(s)
Diclofenac (DCF), the most widely consumed non-steroidal anti-inflammatory drug
(NSAID) worldwide, is associated with adverse typical effects, including gastrointestinal (GI)
complications. The present study aims to better understand the topical toxicity induced by DCF
using membrane models that mimic the physiological, biophysical, and chemical environments of
GI mucosa segments. For this purpose, phospholipidic model systems that mimic the GI protective
lining and lipid models of the inner mitochondrial membrane were used together with a wide set of
techniques: derivative spectrophotometry to evaluate drug distribution at the membrane; steady-state
and time-resolved fluorescence to predict drug location at the membrane; fluorescence anisotropy,
differential scanning calorimetry (DSC), dynamic light scattering (DLS), and calcein leakage studies to
evaluate the drug-induced disturbance on membrane microviscosity and permeability; and small- and
wide-angle X-ray scattering studies (SAXS and WAXS, respectively), to evaluate the effects of DCF at
the membrane structure. Results demonstrated that DCF interacts chemically with the phospholipids
of the GI protective barrier in a pH-dependent manner and confirmed the DCF location at the lipid
headgroup region, as well as DCF’s higher distribution at mitochondrial membrane contact points
where the impairment of biophysical properties is consistent with the uncoupling effects reported for
this drug.
Description
Keywords
Diclofenac NSAIDs Derivative spectrophotometry Steady-state and time-resolved fluorescence Steady-state anisotropy DLS DSC SAXS WAXS Gastrointestinal topical toxicity