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

Herbicide-Intercalated Zinc Layered Hydroxide Nanohybrid for a Dual-Guest Controlled Release Formulation

Herbicides, namely 4-(2,4-dichlorophenoxy) butyrate (DPBA) and 2-(3-chlorophenoxy) propionate (CPPA), were intercalated simultaneously into the interlayers of zinc layered hydroxide (ZLH) by direct reaction of zinc oxide with both anions under aqueous environment to form a new nanohybrid containing both herbicides labeled as ZCDX. Successful intercalation of both anions simultaneously into the interlayer gallery space of ZLH was studied by PXRD, with basal spacing of 28.7 Å and supported by FTIR, TGA/DTG and UV-visible studies. Simultaneous release of both CPPA and DPBA anions into the release media was found to be governed by a pseudo second-order equation. The loading and percentage release of the DPBA is higher than the CPPA anion, which indicates that the DPBA anion was preferentially intercalated into and released from the ZLH interlayer galleries. This work shows that layered single metal hydroxide, particularly ZLH, is a suitable host for the controlled release formulation of two herbicides simultaneously