Window of detection of cocaine-related alkaloids in oral fluid collected with the FloqSwab™ after coca tea consumption.

Coca tea is a popular drink in some countries of South America, where it is presented as a safe energy preparation, based on a limited total content of cocaine of ∼3-5 mg. Tea bags can be bought with no legal considerations in these countries both by locals and tourists, but its consumption can have consequences when consumed overseas. Driving under the influence of cocaine is banned in most of the places in the world and can be documented by oral fluid testing. A study was implemented with coca tea bags (Coca & Muna) purchased in Peru, after a French attorney-at-law contacted the laboratory to assess the involvement of coca tea in the positive oral fluid results of a driver. Ten healthy volunteers consumed 250 mL of coca tea containing 4.5 mg of cocaine. No volunteer reported any change in behavioral effects after consumption of the coca tea. Oral fluid was collected with a swab (FloqSwab™, Copan) over 8 h to follow the elimination of cocaine and its major metabolites (benzoylecgonine and ecgonine methylester). This is the procedure used by the French police. All samples were analyzed by UHPLC-MS-MS after Quantisal™ buffer desorption. As the device does not allow measurement of the amount of collected fluid, the results are qualitative. This is in accordance with the French law that requires a yes or no response about the presence of cocaine, with a minimum required performance level of 10 ng/mL of cocaine or benzoylecgonine. Parent cocaine was identified for 30-120 min. Benzoylecgonine and ecgonine methylester were identified between 1 and 8 h, with a large inter-individual variation. Although it is generally accepted that a 4-5 mg cocaine dose has no significant pharmacological effect, the consumption of coca tea can lead to the suspension of a person's driving license due to a positive oral fluid test.

Responsive microgels-based colloidosomes constructed from all-aqueous pH-switchable coacervate droplets.

HYPOTHESIS: Colloidosomes made of stimuli-responsive microgels offer the opportunity to design polymeric capsules with a hierarchical and tunable pore distribution. Coacervates stabilized by a microgel monolayer represent a unique strategy to build colloidosomes from all-aqueous emulsion drops, while exploiting the sequestration and dissolution properties of the coacervates. EXPERIMENTS: Methacrylated poly(N-isopropylacrylamide) (pNIPAM) microgels are used to stabilize coacervates made of an ampholyte polymer at a pH close to its isoelectric point. They are further cross-linked under UV-irradiation. The resulting assemblies are studied by means of confocal microscopy. Their permeability towards dextrans and nanoparticles is studied before and after dissolution of the coacervate. FINDINGS: PNIPAM microgels are found to stabilize the coacervates by adsorbing at their surface. Inter cross-linking the microgels results in the formation of an elastic colloidosome that persists after the coacervate dissolution and withstands surface deformations up to about 200%. The coacervate is exploited as a sequestrating core to entrap a water-soluble payload, which can be further released upon coacervate dissolution, while the membrane exhibits a size-selecting permeability. The membrane properties can also be switched by the volume phase transition of the microgels. Coacervate-embedded colloidosomes open new perspectives in the area of encapsulation/extraction and controlled transport of water-soluble/dispersed species.