DEXAMETHASONE AND DEXAMETHASONE PHOSPHATE AND THEIR EFFECTS ON DMPC MEMBRANE MODELS.

C. I. CÁMARA; CROSIO, MATÍAS A.; N. WILKE; L. M. YUDI

Graz

Congreso; 7th European Joint Theoretical/Experimental Meeting on Membranes; 2021

UniGraz - NAWI Graz

Dexamethasone (Dex) and Dexamethasone phosphate (Dex-P) are synthetics glucocorticoids with a high anti-inflammatory and immunosuppressor action[1]. Both drugs are used in a wide range of diseases from tumor to asthma attack[2?4].Recently, Dexamethasone has become more renowned because it reduces the mortality in critical patients with SARs-COVID-19 connected to assisted breathing[5,6].We studied the variation of the properties of DMPC monolayers as Dex and Dex-P inserted into the film in different molar proportions. With this aim, we used complementary techniques such as compression isotherms, Brewster angle microscopy (BAM), and insertion experiments. Vesicle shape fluctuations were also analyzed.Results: The hybrid films DMPC: Dex had lower compressibility modulus in the liquid-condensed (LC) phase, as well as lower reflectivity than pure DMPC monolayers. When Dex molar fraction was higher than 0.5, the liquid-expanded (LE)/LC phase transition blurred, and above 0.8, BAM images showed the presence of aggregates. In contrast, the presence of Dex-P in DMPC monolayer increased the compressibility modulus of the LC phase without affecting its reflectivity, after 0.7 of Dex-P some aggregates were also found. Insertion experiments indicates that Dex induced higher surface pressure changes, with a higher exclusion pressures than Dex-P. Conclusion: Both drugs penetrate DMPC monolayers up to high surface pressures. Dex, due to its hydrophobic character, disrupts the lipid surface organization of DMPC, altering the nucleation process and making the monolayer more compressible. This effect was opposite to that observed with Dex-P.