Application of Solid Dispersion Technique to Improve Solubility and Sustain Release of Emamectin Benzoate

Abstract

The solid dispersion technique, which is widely used in the medical field, was applied to prepare a pesticide dosage form of emamectin benzoate (EM). The preparation, physicochemical characterization, aqueous solubility, release dynamics, photolytic degradation, bioactivity, and sustained-release effects of the prepared EM solid dispersions were studied by a solvent method, using polymer materials as the carriers. Water-soluble polyvinyl pyrrolidone (PVP) K30 and water-insoluble polyacrylic resin (PR)III were used as the carriers. The influence of various parameters, such as different EM:PVP-K30 and EM:PRIII feed ratios, solvent and container choices, rotational speed and mixing time effects on pesticide loading, and the entrapment rate of the solid dispersions were investigated. The optimal conditions for the preparation of EM-PVP-K30 solid dispersions required the use of methanol and a feed ratio between 1:1 and 1:50, along with a rotational speed and mixing time of 600 rpm and 60 min, respectively. For the preparation of EM-PRIII solid dispersions, the use of methanol and a feed ratio between 1:4 and 1:50 were required, in addition to the use of a porcelain mortar for carrying out the process. Under optimized conditions, the prepared EM-PVP-K30 solid dispersions resembled potato-like, round, and irregular structures with a jagged surface. In contrast, the EM-PRIII solid dispersions were irregular solids with a microporous surface structure. The results of X-ray powder diffraction (XRD), differential scanning calorimetry (DSC), ultraviolet (UV) spectrometry, and infrared (IR) spectrometry showed that the solid dispersions were formed by intermolecular hydrogen bonding. The solid dispersion preparation in PVP-K30 significantly improved the solubility and dissolution rate of EM, particularly the aqueous solubility, which reached a maximum of 37.5-times the EM technical solubility, when the feed ratio of 1:10 was employed to prepare the dispersion. Importantly, the wettable powder of EM-PVP-K30 solid dispersion enhanced the insecticidal activity of EM against the Plutella xylostella larvae. Furthermore, the solid dispersion preparation in PRIII afforded a significant advantage by prolonging the EM technical release in water at a pH below 7.0, especially when the PRIII content in solid dispersions was high. While the amplified toxicity of the wettable powder of EM-PRIII solid dispersions against the P. xylostella larvae showed no significant differences from that of the EM technical, the long-term toxicity under the field condition was much better than that of the commercially available EM 1.5% emulsifiable concentrate. Notably, solid dispersions with both the PVP-K30 and PRIII carriers reduced the effect of UV photolysis.

Sustained-Release Solid Dispersion of High-Melting-Point and Insoluble Resveratrol Prepared through Hot Melt Extrusion to Improve Its Solubility and Bioavailability

“…Sustained-release (SR) dosage forms can reduce the dosing frequency by maintaining therapeutically effective drug concentrations over a prolonged period of time and improve patient compliance. Among various formulation approaches for sustained drug release, preparing matrices with insoluble polymers using the SD technique is an effective way to produce SR oral dosage forms [ 22 ]. In polymer matrix systems, drug molecules are homogeneously distributed throughout a matrix, and drug release rate is controlled by water-soluble or erodible matrices consisting of various hydrophilic or hydrophobic polymeric excipients [ 23 ].…”

Preparation and Evaluation of Silymarin‐Loaded Solid Eutectic for Enhanced Anti‐Inflammatory, Hepatoprotective Effect: In Vitro–In Vivo Prospect

“…The X-ray diffraction spectrum of pure SL is depicted in Figure 2 and 28.95 °at 2θ angle. The intense peaks assigned for respective miller indices confirm the crystalline nature [34]. The resultant solid dispersion formed by solvent evaporation methods can be able to successfully convert into amorphous form.…”

“…FTIR spectrum of SSD3 is represented in Figure 1(d) , which displayed distinct vibration intensity describing the successful formation of solid dispersion. The spectral intensity slightly increases, which may possibly be due to the weak Van der Waals interaction or hydrogen bonding between water molecule and PVP K30-encapsulating SL [ 31 , 34 ]. A broad peak appeared at 3628 cm −1 , which showed strong interaction between SL and PVP K30 representing hydroxyl stretching.…”

“…A strong peak observed at 1670 cm −1 was due to C=O stretching, which may be emerged from both SL and PVP K30. The small peak was observed at 1508 cm −1 represents N binding due to the presence of C-N in the structure of PVP K30 [ 34 ]. Two new peaks formed at 1423 cm −1 and 1374 cm −1 represent C-H bending were emerged due to physical interaction.…”

A long‐lasting biological larvicide against the dengue vector mosquito Aedes albopictus

“…In addition, many Bit products are less water soluble than other synthetic insecticides, which results in the short residual activity of current preparations under field conditions. Solid dispersion is the molecular dispersion of drugs in a polymer matrix, which leads to improved solubility and hence improved bioavailability 25 …”