Vol.:(0123456789) Polymer Bulletin https://doi.org/10.1007/s00289-018-2456-1 1 3 ORIGINAL PAPER Core shell microcapsules of neem seed oil extract containing azadirachtin and biodegradable polymers and their release characteristics Kanyarat Sittipummongkol 1  · Piyachat Chuysinuan 2  · Supanna Techasakul 2  · Penwisa Pisitsak 1  · Chiravoot Pechyen 1 Received: 8 June 2017 / Revised: 8 March 2018 / Accepted: 20 July 2018 © Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract Azadirachtin is a biologically active constituent of neem seed oil, exhibiting medici- nal and pesticidal properties. This work reports on the encapsulation of neem seed oil extract within three diferent polymeric shells: polyvinyl alcohol (PVA), gum arabic (GA), and whey protein isolate/maltodextrin (WPI/MD), using spray drying. The obtained roughly spherical microcapsules had average sizes of 28.84 ± 11.86, 32.43 ± 13.06, and 52.88 ± 17.33 µm (obtained from PVA, GA, and WPI/MD, respectively). Fourier-transform infrared spectroscopy confrmed the presence of the core and shell components, in addition to surface functional groups. Encapsulation efciencies for neem seed oil proved higher in smaller microcapsules, although ef- ciency values of 60–92% were obtained in all cases. In vitro release of neem seed oil from the microcapsules followed the Ritger–Peppas model, as governed by Fickian difusion. From these results, the association of botanical insecticides within biopol- ymer cores ofers considerable potential for increasing agricultural production levels and reducing impacts on the environment and human health. Keywords Microcapsules · Azadirachtin · Insecticides · Polyvinyl alcohol · Gum arabic · Whey protein isolate · Maltodextrin * Chiravoot Pechyen chiravoot.p@gmail.com 1 Division of Materials and Textile, Faculty of Science and Technology, Thammasat University, Pathumthani 12120, Thailand 2 Laboratory of Organic Synthesis, Chulabhorn Research Institute, Bangkok 10210, Thailand