Minimizing Drug Extraction via Simultaneous Binding and Coagulation

Nova Southeastern University, Davie, Florida, USA

Objective. The study was conducted to determine the combined effect of binding and coagulation on drug extraction from a bentonite drug dispersion. Background. Previously, our laboratory has shown the successful use of bentonite clays to prevent drug extraction for IV abuse due to its complex formation with cationic drugs. In this work, we have enhanced the deterrence capacity of bentonite clays by coagulating the bentonite particles during the extraction process. Methods. A suspension was prepared by dispersing calcium bentonite (50, 75, and 100 mg) into a 10 mL solution (2.5 mg/mL) of dextromethorphan HBr (DMX), followed by an addition of 2 mg of PEO. Non-coagulated (control) samples were also prepared in a similar way without addition of PEO. All samples were analyzed by a UV-spectrophotometer at a wavelength of 271 nm. The % of drug entrapped was measured indirectly from the amount remaining in the filtrate. The amount of filtrate recoverable after dispersion of bentonite clay with and without coagulant was measured using a graduated cylinder. Results. A higher % of drug entrapped within coagulated clays in all dispersions compared to the control. As the amount of clay in the drug solution was increased, about 5-6.5 % increase in drug entrapment was observed. With the dispersed system, the recoverable filtrate volume was 9.4 mL whereas, the recoverable amount of filtrate was 8.6 mL for the coagulated system. Conclusion. The coagulation process affected the drug extraction process by causing around a 6% increase in drug entrapment and an 8% decrease in solvent recovery compared to a non-coagulated dispersed clay system.