ABSTRACT:
This study investigates the formulation and characterization of stable microemulsions using neem oil methyl ester as the oil phase and cardphenol ethoxylate surfactants with varying hydrophilic-lipophilic balance (HLB) values. Neem oil methyl ester was characterized and exhibited favourable physicochemical properties including specific gravity of 0.873, acid value of 0.12, and viscosity of 4.3 mm²/s at 40°C. Eight surfactant blends were prepared using cardphenol ethoxylated 9 mole (CP-9, HLB 11.9) and cardphenol ethoxylated 15 mole (CP-15, HLB 13.9) in different proportions, with and without isopropyl alcohol ethoxylated 2 moles (IPA-2) as co-solvent. Pseudo-ternary phase diagrams were constructed using the aqueous titration method to identify microemulsion regions for each blend. Both water-in-oil (W/O) and oil-in-water (O/W) type microemulsions were successfully formulated and characterized for pH, density, electrical conductivity, and particle size. The W/O microemulsions exhibited particle sizes ranging from 99 to 174 nm with conductivity values between 70.3 and 100 µS/cm, while O/W microemulsions showed particle sizes of 121 to 179 nm with higher conductivity values ranging from 230.4 to 344.2 µS/cm. All formulations demonstrated excellent centrifuge stability both initially and after 30 days of storage. The results indicate that Blend 5 (90% CP-9, 10% CP-15 with IPA-2 at 1:1 ratio, HLB 12.1) produced the smallest particle size of 99 nm for W/O microemulsions, while Blend 5 also yielded the smallest O/W particle size of 121 nm, suggesting optimal surfactant composition for enhanced microemulsion stability. These findings demonstrate the potential of cardphenol ethoxylate-based surfactant systems for developing stable neem oil methyl ester microemulsions with applications in agricultural formulations and bio-based delivery systems.
Cite this article:
Harshal Patil, Jyotsna Waghmare. Formulation and Characterization of Cardphenol Ethoxylate Based Microemulsion of Neem Oil Methyl Ester. International Journal of Technology. 2026; 16(1):35-2. doi: 10.52711/2231-3915.2026.00004
Cite(Electronic):
Harshal Patil, Jyotsna Waghmare. Formulation and Characterization of Cardphenol Ethoxylate Based Microemulsion of Neem Oil Methyl Ester. International Journal of Technology. 2026; 16(1):35-2. doi: 10.52711/2231-3915.2026.00004 Available on: https://www.ijtonline.com/AbstractView.aspx?PID=2026-16-1-4
6. REFERENCE:
1. Sarika S. Lokhande. Microemulsions as Promising Delivery Systems: A Review. Asian J. Pharm. Res. 2019; 9(2): 90-96.
2. Kanchan R. Pagar, A. B. Darekar. Nanoemulsion: A new concept of Delivery System. Asian J. Res. Pharm. Sci. 2019; 9(1):39-46.
3. Mahendra Prajapati, Shradha Shende, Vivek Jain, Akhil Gupta, Manoj Kumar Goyal. Formulation and In vitro Percutaneous Permeation and Skin accumulation of Voriconazole Microemulsified Hydrogel. Asian Journal of Pharmacy and Technology. 2021; 11(4):267-2.
4. Sushant R. Jagtap, D.G Phadtare, R.B. Saudagar. Microemulsion: A Current Review. Res. J. Pharm. Dosage Form. and Tech. 2016; 8(2):161-170.
5. Naresh Mandavi1, Nazneen Ansari1, Ravi Bharti1, N Syed Abdul Kader1, Gyanesh Kumar Sahu2, Harish Sharma. Microemulsion: A Potential Novel Drug Delivery System. Res. J. Pharm. Dosage Form. and Tech. 2018; 10(4): 266-271.
6. Benelli, G., Canale, A., Toniolo, C., Higuchi, A., Murugan, K., Pavela, R., and Nicoletti, M. (2017). Neem (Azadirachta indica): towards the ideal insecticide. Natural product research, 31(4), 369–386. https://doi.org/10.1080/14786419.2016.1214834
7. Sumit Yadav, Kawtikwar PS, Sakarkar DM, Gholse YN, Ghajbhiye SD. Microemulsion: A Review. Research J. Pharm. and Tech.2 (3): July-Sept. 2009,;Page 441-448.
8. A.Veeramanoharan, S-C. Kim, Surfactant properties and biodegradation of polyethoxylates from phenolic lipids, RSC Advances, 2024. Available at: https://pubs.rsc.org/en/content/articlehtml/2024/ra/d4ra04684f
9. Surfactant properties and biodegradation of polyethoxylates from phenolic lipids, J. H. P. Tyman and I. E. Bruce, Journal of Surfactants and Detergents, Vol. 7 (2004), pp. 169-173.
10. C. Li, H. Yu, F. Li, Z. Zhang, J. Huang and J. Wang, “Physicochemical properties of series of cardanol polyoxyethylene ether carboxylates with different ethoxylation unit at the interface”, Journal of Dispersion Science and Technology, Vol. 40, No. 1 (2019), pp. 9-16
11. K. Chen, Y. Shi, X. Liu, “Facile synthesis of a cardanol-based levelling agent as a biodegradable alternative to tristyrylphenol ethoxylates for the dyeing of polyester fabric”, Colouration Technology, Vol. 138, No. 3 (2022), pp. 266–277
12. Shao, H., Xi, N. and Zhang, Y. Microemulsion formulation of a new biopesticide to control the diamondback moth (Lepidoptera: Plutellidae). Sci Rep 8, 10565 (2018). https://doi.org/10.1038/s41598-018-28626-0
13. Xu, J., Fan, Q. J., Yin, Z. Q., Li, X. T., Du, Y. H., Jia, R. Y., Wang, K. Y., Lv, C., Ye, G., Geng, Y., Su, G., Zhao, L., Hu, T. X., Shi, F., Zhang, L., Wu, C. L., Tao, C., Zhang, Y. X., and Shi, D. X. (2010). The preparation of neem oil microemulsion (Azadirachta indica) and the comparison of acaricidal time between neem oil microemulsion and other formulations in vitro. Veterinary parasitology, 169(3-4), 399–403. https://doi.org/10.1016/j.vetpar.2010.01.016
14. Attaphong C., Do L., Sabatini D. A. Vegetable oil-based microemulsions using carboxylate-based extended surfactants and their potential as an alternative renewable biofuel. Fuel. 2012;94:606-613. doi:10.1016/j.fuel.2011.10.048
15. Du, Y. H., Jia, R. Y., Yin, Z. Q., Pu, Z. H., Chen, J., Yang, F., Zhang, Y. Q., and Lu, Y. (2008). Acaricidal activity of extracts of neem (Azadirachta indica) oil against the larvae of the rabbit mite Sarcoptes scabiei var. cuniculi in vitro. Veterinary parasitology, 157(1-2), 144–148. https://doi.org/10.1016/j.vetpar.2008.07.011
16. Ritesh Kumawat Harshal Patil, Jyotsna Waghmare. Unlocking the Potential of Hazelnut oil: Formulation and Characterization of a Novel Microemulsion for Enhanced Applications. Research Journal of Science and Technology. 2024; 16(2):119-4.
17. Harshal Patil, Jyotsna Waghmare. Formulation and Characterization of Natural Foaming Face Wash Utilizing Hazelnut Oil Microemulsion for Enhanced Skin Nourishment and Stability. Research Journal of Topical and Cosmetic Sciences. 2025; 16(2):86-0.
18. Harshal Patil, Jyotsna Waghmare. Harnessing the Power of Non-Conventional Vegetable Oils: A Review of Sustainable Product Development. International Journal of Technology. 2024; 14(1):59-5.
19. Harshal Patil, Ritesh Kumawat, Jyotsna Waghmare. Formulation and Characterization of Microemulsions containing Argan Oil: A Promising Delivery System for Cosmeceutical Applications. Research Journal of Pharmacy and Technology. 2025;18(5):2132-6.