**5. Recent advances in suspension concentrate formulations**

Effect of polymeric surfactant on physical stability has investigated in suspension concentrate. Polymeric surfactants provide high critical micellar concentration (CMC) and reduced Gibbs-free energy ΔG [15]. In another study, silicone surfactant is used as adjuvants in the SC formulation that results in high performance of surfactant and improves the physical stability and the quality of the formulation [16].

Particle size is also an important factor for stability as well as bio-efficacy enhancement. In a study, Vineela et al. [17] have reported that in *Bacillus thuringenesis* SC formulations, further reduction of particle size enhanced the bio-efficacy of formulation against *Spodoptera litura* (Lepidoptera: Noctuidae).

Some pesticides are photosensitive and easily decomposed. In a study, an aminemodified ligno-sulfonate surfactant was synthesized to make the SC formulation anti-photolysis [18]. Similar advancements have been conducted in IPFT on botanical-based formulations to inhibit photolysis. In addition to this, IPFT has developed several other UV protectant-based SC formulations for various SC formulations.

Entomopathogenic fungus, *Beauveria bassiana*, has been formulated as SC against *Helicoverpa armigera* larvae with LC50 value of 61.22 mg l−1 after 3 days of application [19]. Several other entomo-pathogenic fungi have been formulated as SC formulation by IPFT against various insect pests of different economically important crops such as spices and oil crops of Asian region.

Along with this IPFT has developed many synthetic and botanical pesticide SC formulations for agricultural pest control which include Isoproturon 50SC, Carbendazim 50SC, Sulfur 52SC, fipronil 5SC, thiomethxam 14.1% + Lamda cyhalothrin 10.6% SC, metamitron 70 SC, Neem SC, etc.

#### **5.1 Capsule suspension (CS)**

Capsule suspension (CS) is water-based slow release formulation containing active ingredient encapsulated inside microcapsules up to 10 microns size (**Figure 8**). CS formulation is a stable suspension of micro-capsules containing active ingredients and these microcapsules are synthesized by interfacial polymerization mechanism. CS formulations provide regulated, slow, and delayed the release of pesticides. This formulation is safer delivery mode by giving protection from toxic ingredients and stops the pesticide rate of degradation.

#### **5.2 Advanced features of CS**

CS are water-based (free from any organic solvent) homogeneous and uniform suspension formulation. Its application is safe, and provides enhanced and efficient bio-safety with reduced phytotoxicity. In order to develop CS formulation, the active ingredients should have low solubility in water and altogether hydrolytically stable. The pesticide from microcapsules gets slowly released after application. The CS formulations are slow release formulations and theses formulations prolong the availability of pesticide at target site. The CS formulation reduces environmental

#### *Agricultural Development in Asia - Potential Use of Nano-Materials and Nano-Technology*

**Figure 8.**

*Schematic representation of capsulated suspension formulation procedure a. and its application b.*

contamination and leaching of pesticide and degradation of active ingredient by environmental factors like sunlight.

In a recent study, it was found that carboxy, methyl cellulose (CMC) and diallyl, dimethyl, ammonium chloride (DMDAAC) as monomers are the effective encapsulating agents of avermectin pesticide. This capsulated form gave higher performance and has excellent UV protecting property [20]. Thus, IPFT has developed CS for seed dressing for targeted delivery of pesticides without any wastage in environment [21].

Cyhalothrin is the most effective and broad-spectrum pesticide used in Central Asia. It has dual mode of action contact as well as systemic. Most efficient CS formulations developed by IPFT for sustainable agricultural applications are Lambda Cyhalothrion 10CS and Lambda Cyhalothrin 4.9CS.

#### **5.3 Microemulsion**

Microemulsion (ME) is the most efficient delivery system of botanicals as well as synthetic pesticides. By definition- "ME is a system of water, oil, and an amphiphile which is a single optically isotropic and thermodynamically stable liquid solution" [22]. *Vital Role of IPFT in Development of New-Generation Pesticide Formulation for Crop… DOI: http://dx.doi.org/10.5772/intechopen.101134*

Droplet size of ME is in nano-range, that is, 10 nm–20 nm. Based on dispersion medium, ME can be classified into two categories: O/W ME and W/O ME. Aqueous dilution of ME is required before spray application (**Figure 8**). Being a new-generation formulations, the characteristic features of MEs are nano sized, thermodynamically stable system with good penetrability, quick spreading ability, low and zero interfacial tension, and extended shelf life formulation.
