Synthesis of a monophasic nanohybrid for a controlled release formulation of two active agents simultaneously

A new monophasic nanohybrid containing two phenoxyherbicides anions, 4-(2,4-dichlorophenoxy)butyrate (DPBA) and 2-(3-chlorophenoxy)propionate (CPPA), was successfully synthesized. The two anions were simultaneously intercalated into the inorganic interlayers of zinc-aluminum-layered double hydroxide (ZAL) for the formation of a nanohybrid, ZAL-CPPA-DPBA (NCDX) by an anion-exchange method. Powder X-ray diffraction, direct-injection mass spectrometry and Fourier transform infrared spectroscopy studies confirmed the dual intercalation of both anions into the host interlayer regions. The well-ordered, layered nanohybrid was synthesized using 0.1 M solution of both anions. The basal spacing expanded from 8.9 Å in ZAL to 27.43 Å in the nanohybrid. The release of both anions from the nanohybrid into an aqueous solution of 0.001 M sodium carbonate was found to be governed by pseudo second-order kinetics. This release demonstrates the potential application of layered materials as reservoirs and delivery system, especially when multiple active agents are used simultaneously in the formation of an organic–inorganic host–guest nanohybrid with controlled-release properties.

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► Two herbicides were simultaneously intercalated into Zn-Al-LDH.
► DPBA anion is the dominant species in the LDH interlayers.
► Simultaneous release of both herbicides is controlled by pseudo second-order kinetics.
► LDHs as a host and delivery system for multiple active agents.