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Innovation through Formulation – Oil Dispersion
Sep. 1, 2015
OXITENO
BrazilFollow
BrazilCo-authored by: Fernanda Costa, Priscila Castelani and André Conde
The global crop protection market has grown from US$ 30 billion in 2006 to US$ 54 billion in 2013. On the other hand, there has been a decline in the rate of new active ingredients in development and reaching the market (fig 1).
Figure 1. AIs in development
Bringing a new product to market is costly and difficult and the regulatory barriers are getting higher. For example, it is estimated that the cost for Research, Development and Registration of a new agrochemical is about US$ 256 million (based on 2009 Crop Life America/ECPA study) and it takes up to 10 years for registration of a synthetic pesticide from time of discovery. Depending on the regulatory scenario in the country, it takes longer.
This does not mean a decline in innovation. Companies have turned to formulation technology to extend the life of products and to give them a technical or regulatory advantage. In particular, it presents opportunities to generic formulation companies to enter the market when proprietary compounds come off patent.
We would like to demonstrate this strategy by presenting a case study on Insecticide Formulation Development.
Oil Dispersion Formulation
The recent phase out of insecticides endosulfan and methamidophos in the Brazilian market has forced many companies to develop new insecticide formulations to replace these popular pesticides used primarily to control insects in soybean and cotton crops.
Neonicotinoid and pyrethroids are obvious choices among non-patented pesticides. Due to their physico-chemical properties, most pyrethroids usually are formulated as ECs (Emulsifiable Concentrate) while neonicotinoids as SCs (Suspension Concentrate). To formulate a mixture of these active ingredients, the natural choice would be a SE (SuspoEmulsion), but even for skilled formulators, development of SEs is not an easy task and very time consuming. In this way, Oxiteno developed an OD (Oil Dispersion) system, where neonicotinoids can be suspended in the oil phase, while pyrethroids are solubilized in it, making easily feasible to formulate different active ingredients with different solubilities in oil and water (fig 2).
Figure 2. Different approaches on neonicotinoid + pyrethroid formulation
New OD formulations are of great interest as they can be considered “adjuvanted” suspension concentrates, i.e., SCs or flowables that already contain oil-based adjuvants commonly added to tank-mix products. Most oil-based tank mix adjuvants are primordial for improvement and guarantee of biological efficacy of SCs, which are known for not having the highest efficacy due to the fact that the active ingredient are suspended particles. In addition, ODs show another advantage compared with SCs regarding the hydrolysis of active ingredients, which is overcome in such oil-based system.
On the other hand, the active ingredient must be insoluble in the oil phase (< 200 ppm) to be suspended and to avoid crystal growth during long-term storage. Another issue is that ODs usually have a high viscosity at low shear rate to prevent sedimentation jeopardizing the self-emulsification process during dilution in water. In this way, the great challenge in the development of OD formulations is to achieve shelf-life stability and desired behavior when diluted in water for spraying.
A mix of neonicotinoid and pyrethroid was successfully formulated in an OD formulation-type. For that, new products as dispersants, emulsifiers and rheology modifiers were developed to be suitable products for this type of formulation since the oil phase requires different surfactants (fig 3). Accelerated stability and rheology tests showed that these formulations were stable in a long-term shelf life. In addition, by tests upon dilution in water it was demonstrated that the formulations gave the desirable performance for tank mixing and spraying.
Figure 3. Formulation process
To prove the biological efficacy of the OD formulation and compare the performance in the field of insecticides OD formulation versus other insecticides formulation types and tank mixtures, the final formulations were subjected to field trials in cotton crops at Primavera do Leste, Mato Grosso, Brazil, during September 2012 and March 2013 (summer season). The target insect evaluated in this study was cotton-boll weevil -Anthonomus grandis Boh. (Coleoptera: Curculionidae), which is responsible for the main damages to cotton buds in Brazil. The blue treatments are market references. Commercial 1 and Commercial 2 are formulated as Suspension Concentrates and the third one is a Tank Mix. The OD formulations are green and Orange treatments. The last treatment in orange has similar dose to the market references and the effect of lower AIs dose was also evaluated.
Figure 4. Field trials results
By these results, it is possible to conclude that formulation choice affects bioefficacy of the same active ingredients. The OD formulations improved performance even at lower doses and seem to indicate a long lasting effect. In fact, these OD formulations behave as “adjuvanted” suspensions concentrates and dispersants, emulsifiers and rheology modifiers used in this development showed to be a great tool for OD formulation technology.
Innovation through formulation is a smart strategy for agrochemical companies and could add new features for old active ingredients. Furthermore, the combination of different active ingredients and other compounds within a single formulation is becoming more common and more complex. This strategy is being used not only to reduce costs and develop a new product, but also - and more important - this is an important strategy to face the pesticide resistance issue.
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Source: OXITENO
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