SYNERGISTIC OPTIMIZATION OF EUCALYPTUS OIL NANOEMULSIONS: PHYSICOCHEMICAL STABILITY AND CHEMICAL DEGRADATION PROFILES UNDER ACCELERATED STRESS
DOI:
https://doi.org/10.22159/ijap.2026v18i3.58299Keywords:
Eucalyptus oil nanoemulsion, Eucalyptol, Quality by design, Accelerated stability, Chemical degradationAbstract
Objective: To rationally design and optimize a eucalyptus oil nanoemulsion through a Quality by Design (QbD) framework while establishing an integrated dual-stability strategy that simultaneously interrogates physicochemical robustness and chemical integrity of eucalyptol under accelerated stress conditions.
Methods: Formulation optimization was performed using a full factorial experimental design (2⁴) to investigate the effects of surfactant proportion, cosurfactant proportion, surfactant type, and cosurfactant type on critical quality attributes (CQAs), including percent transmittance and viscosity. Statistical analysis was conducted using analysis of variance (ANOVA), followed by desirability function optimization. Physicochemical stability was evaluated through droplet size, polydispersity index (PDI), pH, viscosity, and visual observation, while chemical stability of eucalyptol was monitored using GC–MS during accelerated storage at 40 ± 2 °C/75 ± 5% RH for three months.
Results: The optimized nanoemulsion achieved high optical clarity (92.41%), low viscosity (27.59 cPs), and a desirability value of 0.972, with a statistically significant predictive model for transmittance (R² = 0.9987). The formulation maintained nanoscale droplet size (≈22–25 nm), low PDI (<0.30), stable pH, and absence of phase separation throughout storage. However, GC–MS analysis revealed a time-dependent decline in eucalyptol content despite preserved physicochemical stability, indicating a dissociation between droplet integrity and molecular retention.
Conclusion: The proposed integrated dual-stability framework advances current nanoemulsion development paradigms by demonstrating that physicochemical stability alone is insufficient for volatile therapeutic agents. Early incorporation of chemical stability evaluation is essential to achieve formulation reliability and translational relevance.
References
1. Chen X, Zhou CW, Fu YY, Li YZ, Chen L, Zhang QW, Chen YF. Global, regional, and national burden of chronic respiratory diseases and associated risk factors, 1990-2019: Results from the Global Burden of Disease Study 2019. Front Med (Lausanne). 2023 Mar 28;10:1066804. doi: 10.3389/fmed.2023.1066804. PMID: 37056726; PMCID: PMC10088372.
2. Juergens UR, Dethlefsen U, Steinkamp G, Gillissen A, Repges R, Vetter H. Anti-inflammatory activity of 1.8-cineol (eucalyptol) in bronchial asthma: a double-blind placebo-controlled trial. Respir Med. 2003 Mar;97(3):250-6. doi: 10.1053/rmed.2003.1432. PMID: 12645832.
3. Sutrisna INGT, Dewi NNA, Wati DK, Linawati NM, Wirasuta IMAG. A systematic review of eucalyptol as an innovative therapeutic agent for respiratory diseases. Int J Appl Pharm. 2025;17(3):93-100. doi:10.22159/ijap.2025v17i3.53775.
4. Dasgupta N, Ranjan S, Gandhi M. Nanoemulsion ingredients and components. Environ Chem Lett. 2019;17(2):917-928. doi:10.1007/s10311-018-00849-7.
5. McClements DJ. Edible nanoemulsions: fabrication, properties, and functional performance. Soft Matter. 2011;7(6):2297-2316. doi:10.1039/C0SM00549E.
6. Schreiner TB, Santamaria-Echart A, Ribeiro A, Peres AM, Dias MM, Pinho SP, Barreiro MF. Formulation and optimization of nanoemulsions using the natural surfactant saponin from Quillaja bark. Molecules. 2020;25(7):1538. doi:10.3390/molecules25071538.
7. Sharma A, Agarwal P, Ahalwat S, Jogpal V, Singh R. Formulation optimization and evaluation of nanoemulsion loaded with plant extract of Crinum latifolium for antiarthritic potential. J Neonatal Surg. 2025;14(Suppl 5):406-416. doi:10.52783/jns.v14.2059.
8. International Council for Harmonisation (ICH). Stability testing of new drug substances and products Q1A(R2). Geneva: ICH; 2003.
9. Jeong JH, Yoon TH, Ryu SW, Kim MG, Kim GH, Oh YJ, Lee SJ, Kwak NW, Bang KH, Kim KS. Quality by Design (QbD)-Based Development of a Self-Nanoemulsifying Drug Delivery System for the Ocular Delivery of Flurbiprofen. Pharmaceutics. 2025 May 9;17(5):629. doi: 10.3390/pharmaceutics17050629. PMID: 40430920; PMCID: PMC12115244.
10. Sugumar S, Ghosh V, Nirmala MJ, Mukherjee A, Chandrasekaran N. Ultrasonic emulsification of eucalyptus oil nanoemulsion: antibacterial activity against Staphylococcus aureus and wound healing activity in Wistar rats. Ultrason Sonochem. 2014 May;21(3):1044-9. doi: 10.1016/j.ultsonch.2013.10.021. Epub 2013 Nov 6. PMID: 24262758.
11. Sugumar S, Mukherjee A, Chandrasekaran N. Eucalyptus oil nanoemulsion-impregnated chitosan film: antibacterial effects against a clinical pathogen, Staphylococcus aureus, in vitro. Int J Nanomedicine. 2015 Oct 1;10 Suppl 1(Suppl 1):67-75. doi: 10.2147/IJN.S79982. PMID: 26491308; PMCID: PMC4599619.
12. Sugumar S, Clarke SK, Nirmala MJ, Tyagi BK, Mukherjee A, Chandrasekaran N. Nanoemulsion of eucalyptus oil and its larvicidal activity against Culex quinquefasciatus. Bull Entomol Res. 2014 Jun;104(3):393-402. doi: 10.1017/S0007485313000710. Epub 2014 Jan 9. Erratum in: Bull Entomol Res. 2014 Jun;104(3):403. PMID: 24401169.
13. Song R, Lin Y, Li Z. Ultrasonic-assisted preparation of eucalyptus oil nanoemulsion: Process optimization, in vitro digestive stability, and anti-Escherichia coli activity. Ultrason Sonochem. 2022 Jan;82:105904. doi: 10.1016/j.ultsonch.2021.105904. Epub 2021 Dec 29. PMID: 34979457; PMCID: PMC8799746.
14. International Council for Harmonisation (ICH). Stability data package for registration applications in climatic zones III and IV Q1F. Geneva: ICH; 2003.
15. Badruddoza AZM, Yeoh T, Shah JC, Walsh T. Assessing and Predicting Physical Stability of Emulsion-Based Topical Semisolid Products: A Review. J Pharm Sci. 2023 Jul;112(7):1772-1793. doi: 10.1016/j.xphs.2023.03.014. Epub 2023 Mar 24. PMID: 36966902.
16. Onaizi SA. Characteristics and pH-Responsiveness of SDBS-Stabilized Crude Oil/Water Nanoemulsions. Nanomaterials (Basel). 2022 May 13;12(10):1673. doi: 10.3390/nano12101673. PMID: 35630894; PMCID: PMC9146945.
17. Cheng Y, Pan Z, Tang L, Huang Y, Yang W. Fabrication of Eco-Friendly Hydrolyzed Ethylene-Maleic Anhydride Copolymer-Avermectin Nanoemulsion with High Stability, Adhesion Property, pH, and Temperature-Responsive Releasing Behaviors. Molecules. 2024 Mar 5;29(5):1148. doi: 10.3390/molecules29051148. PMID: 38474660; PMCID: PMC10934311.
18. Alhamdany A, Saeed A, Alaayedi M. Nanoemulsion and solid nanoemulsion for improving oral delivery of a breast cancer drug. Saudi Pharm J. 2021;29(12):1464-1472. doi:10.1016/j.jsps.2021.09.016.
19. Babick F. Dynamic light scattering (DLS). In: Möhwald H, editor. Characterization of nanoparticles. Amsterdam: Elsevier; 2020. p. 147-176. doi:10.1016/B978-0-12-814182-3.00010-9.
20. Dukhin A, Xu R. Zeta-potential measurements. In: Möhwald H, editor. Characterization of nanoparticles. Amsterdam: Elsevier; 2020. p. 215-247. doi:10.1016/B978-0-12-814182-3.00014-6.
21. Ngo T, Tran T, Le X. Effects of influencing parameters on Eucalyptus globulus essential oil extraction. IOP Conf Ser Mater Sci Eng. 2020;991:012126. doi:10.1088/1757-899X/991/1/012126.
22. Uche C, Okezue M, Amidu I, Byrn S. Model adequacy in assessing predictive performance of regression models in pharmaceutical optimization. Scientia Pharm. 2024;92(4):64. doi:10.3390/scipharm92040064.
23. Campolo O, Giunti G, Laigle M, Michel T, Palmeri V. Essential oil-based nanoemulsions: effect of surfactants and sonication. Ind Crops Prod. 2020;157:112935. doi:10.1016/j.indcrop.2020.112935.
24. Priani SE, Fakih TM, Wilar G, Chaerunisaa AY, Sopyan I. Quality by Design and In Silico Approach in SNEDDS Development: A Comprehensive Formulation Framework. Pharmaceutics. 2025 May 27;17(6):701. doi: 10.3390/pharmaceutics17060701. PMID: 40574014; PMCID: PMC12195909.
25. Pavoni L, Perinelli D, Ciacciarelli A, Quassinti L, Bramucci M, Miano A, et al. Properties and stability of nanoemulsions: how relevant is the type of surfactant? J Drug Deliv Sci Technol. 2020;58:101772. doi:10.1016/j.jddst.2020.101772.
26. Birla D, Khandale N, Bashir B, ShahbazAlam M, Vishwas S, Gupta G, Dureja H, Kumbhar PS, Disouza J, Patravale V, Veiga F, Paiva-Santos AC, Pillappan R, Paudel KR, Goh BH, Singh M, Dua K, Singh SK. Application of quality by design in optimization of nanoformulations: Principle, perspectives and practices. Drug Deliv Transl Res. 2025 Mar;15(3):798-830. doi: 10.1007/s13346-024-01681-z. Epub 2024 Aug 10. PMID: 39126576.
27. Silva H, Cerqueira M, Vicente A. Influence of surfactant and processing conditions in nanoemulsion stability. J Food Eng. 2015;167:89-98. doi:10.1016/j.jfoodeng.2015.07.037.
28. Sharma K, Babaei A, Oberoi K, Aayush K, Sharma S. Essential oil nanoemulsion edible coating in food industry: a review. Food Bioprocess Technol. 2022;15(9):1893-1912. doi:10.1007/s11947-022-02811-6.
29. Park J, Kohn B, Messinger R, Scheler U. Thermal cycling and shear effects on phase-change nanoemulsions. J Phys Chem Lett. 2025;16(3):1045-1052. doi:10.1021/acs.jpclett.5c00307.
30. Li P, Lu W. Effects of storage conditions on physical stability of d-limonene nanoemulsion. Food Hydrocoll. 2016;53:179-186. doi:10.1016/j.foodhyd.2015.01.031.
31. De Oca-Ávalos J, Candal R, Herrera M. Nanoemulsions: stability and physical properties. Curr Opin Food Sci. 2017;16:1-6. doi:10.1016/j.cofs.2017.06.003.
32. Martinez R, Bhanawat A, Yalçın R, Pilon L. Dependent scattering in concentrated nanoemulsions. J Phys Chem C. 2024;128(6):2450-2460. doi:10.1021/acs.jpcc.3c08072.
33. Jakubek Z, Chen S, Zaifman J, Tam Y, Zou S. Lipid nanoparticle and liposome reference materials: storage stability. Langmuir. 2023;39(4):1234-1242. doi:10.1021/acs.langmuir.2c02657.
34. Linxweiler H, Thiesen J, Krämer I. Physicochemical stability of nab-paclitaxel infusion dispersions. Pharmaceutics. 2024;16(11):1137. doi:10.3390/pharmaceutics1611137.
35. Zhu Z, Wen Y, Yi J, Cao Y, Liu F, McClements DJ. Natural vs synthetic surfactants in nanoemulsion stabilization. J Colloid Interface Sci. 2019;536:80-90. doi:10.1016/j.jcis.2018.10.024.
36. Hong I, Kim S, Lee S. Effects of HLB value on oil-in-water emulsions. J Ind Eng Chem. 2018;65:123-130. doi:10.1016/j.jiec.2018.06.022.
37. Zhang W, Jiang J, Cui Z, Binks B. Charged nanoparticles on emulsion stability. J Colloid Interface Sci. 2025;687:100-110. doi:10.1016/j.jcis.2025.02.059.
38. Sohan MSR, Elshamy S, Lara-Valderrama G, Changwatchai T, Khadizatul K, Kobayashi I, Nakajima M, Neves MA. Encapsulation of D-Limonene into O/W Nanoemulsions for Enhanced Stability. Polymers (Basel). 2023 Jan 16;15(2):471. doi: 10.3390/polym15020471. PMID: 36679351; PMCID: PMC9864102.
39. Bezerra I, Santos E, Bisneto J, Perruci P, Ferreira AB, Macêdo D, et al. Physicochemical stability of copaiba balsam oil nanoemulsion. ACS Omega. 2024;9(45):45930-45940. doi:10.1021/acsomega.4c05930.
40. Factorovich M, Molinero V, Scherlis D. Vapor pressure of water nanodroplets. J Am Chem Soc. 2014;136(12):4508-4514. doi:10.1021/ja405408n.
41. Pavoni L, Perinelli DR, Bonacucina G, Cespi M, Palmieri GF. An Overview of Micro- and Nanoemulsions as Vehicles for Essential Oils: Formulation, Preparation and Stability. Nanomaterials (Basel). 2020 Jan 12;10(1):135. doi: 10.3390/nano10010135. PMID: 31940900; PMCID: PMC7023169.
42. Jia J, Yang S, Li J, Liang Y, Li R, Tsuji T, Niu B, Peng B. Review of the Interfacial Structure and Properties of Surfactants in Petroleum Production and Geological Storage Systems from a Molecular Scale Perspective. Molecules. 2024 Jul 8;29(13):3230. doi: 10.3390/molecules29133230. PMID: 38999184; PMCID: PMC11243718.
43. Barradas T, de Holanda e Silva K. Nanoemulsions of essential oils to improve stability and permeability: a review. Environ Chem Lett. 2020;19(1):221-233. doi:10.1007/s10311-020-01142-2.
44. Petralito S, Garzoli S, Ovidi E, Laghezza Masci V, Trilli J, Bigi B, Di Muzio L, Carriero VC, Casadei MA, Paolicelli P. Long-Term Stability of Lavandula x intermedia Essential Oil Nanoemulsions: Can the Addition of the Ripening Inhibitor Impact the Biocidal Activity of the Nanoformulations? Pharmaceutics. 2024 Jan 14;16(1):108. doi: 10.3390/pharmaceutics16010108. PMID: 38258118; PMCID: PMC10821147.
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