Transdermal skin patch based on reduced graphene oxide: A new approach for photothermal triggered permeation of ondansetron across porcine skin.

The development of a skin-mounted patch capable of controlled transcutaneous delivery of therapeutics through thermal activation provides a unique solution for the controlled release of active principles over long-term periods. Here, we report on a flexible transdermal patch for photothermal triggered release of ondansetron (ODS), a commonly used drug for the treatment of chemotherapy-induced nausea and vomiting and used as model compound here. To achieve this, a dispersion of ODS-loaded reduced graphene oxide (rGO-ODS) nanosheets were deposited onto Kapton to produce a flexible polyimide-based patch. It is demonstrated that ODS loaded Kapton/rGO patches have a high drug delivery performance upon irradiation with a continuous laser beam at 980nm for 10min due to an induced photothermal heating effect. The ability of ODS impregnated Kapton/rGO patches as transdermal delivery scaffolds for ODS across the skin is in addition investigated using porcine ear skin as a model. We show that the cumulative quantity and flux of ODS passing the skin are highly depending on the laser power density used. At 5Wcm-2 irradiation, the ODS flux across pig skin was determined to be 1.6µgcm-2h-1 comparable to other approaches. The use of tween 20 as skin enhancer could significantly increase the ODS flux to 13.2µgcm-2h-1. While the skin penetration enhancement is comparable to that obtained using other well-known permeation enhancers, the actual superiority and interest of the proposed approach is that the Kapton/rGO photoactivatable skin patch can be loaded with any drugs and therapeutics of interest, making the approach extremely versatile. The on demand delivery of drugs upon local laser irradiation and the possibility to reload the interface with the drug makes this new drug administration route very appealing.

[Photodegradation of chlorpromazine, a drug-related adverse event]. / La photodégradation de la chlorpromazine, un événement indésirable médicamenteux.

The photodegradation of an active substance during treatment is a rare drug-related adverse event which can sometimes have serious consequences. Health professionals must be aware of the specific storage and administration instructions with regard to chlorpromazine and ensure that they are respected.

Electron beam and gamma radiolysis of solid-state metoclopramide.

PURPOSE: Study the radiolysis of solid-state metoclopramide hydrochloride at various absorbed doses. Elucidate the structure of the degradation products to gain information on the radiolysis mechanisms. METHODS: Solid-state metoclopramide samples were irradiated at several doses with gamma rays and high-energy electrons to evaluate the influence of the dose rate. High-performance liquid chromatography with a diode array detector was used to measure the chemical potency as a function of the absorbed dose and to quantify the degradation products. The characterization of degradation products was performed by liquid chromatography/atmospheric pressure chemical ionization/tandem mass spectrometry. RESULTS: The degradation of solid-state metoclopramide after irradiation was negligible. No qualitative or quantitative differences were observed between gamma and electron beam irradiations (no dose rate effect). Four degradation products that were similar to metoclopramide were detected in trace levels (below 0.1% of the drug concentration) and were not unique to irradiation because they were found in lower amounts in unirradiated metoclopramide. The major degradation product formed after radiation was due to the loss of the chlorine atom from the metoclopramide molecule. CONCLUSION: Solid-state metoclopramide is radioresistant from a chemical point of view and therefore could be a suitable candidate for radiosterilization studies by either gamma rays or high-energy electrons.