Formulation of oil-in-water emulsions for pesticide applications: impact of surfactant type and concentration on physical stability.

Oil-in-water (O/W) emulsions can be utilized as effective pesticide delivery systems in the agricultural industry. In this study, the effects of hydrophile-lipophile balance (HLB), concentration, and location of surfactants on the formation and physical stability of O/W emulsions suitable for pesticide applications was investigated using dynamic light scattering and vertical laser profiling. A non-polar pesticide (lambda-cyhalothrin) was used as a model. The pesticide emulsion with the highest stability was obtained using a commercial non-ionic surfactant (polyoxyethylene castor oil ether, EL-20) with a required HLB value of 10.5. Emulsion stability increased as the surfactant concentration was increased from 2 to 6%, which was attributed to the formation of smaller oil droplets during emulsification. Emulsions prepared with the surfactant initially in the oil phase were more stable than those prepared with it initially in the aqueous phase. The optimum formulation of the pesticide emulsion was determined as follows: 5% lambda-cyhalothrin (active ingredient) and 6% EL-20 (surfactant) dissolved in 5% S-200 (aromatic hydrocarbon, as oil phase), then deionized water up to 100%, which met the quality indicators set by the FAO standards. The present study is expected to provide useful information to improve the stability of pesticide emulsions for commercial applications.

Simple Synthesis Hydrogenated Castor Oil Fatty Amide Wax and Its Coating Characterization.

A simple method for incorporating amine groups in hydrogenated castor oil (HCO) to produce wax for beeswax or carnauba wax substitution in packaging and coating was developed. From the conversion rate of the products, HCO was reacted with ethanolamine at 150°C for 5 h, and the molar ratio of HCO and ethanolamine was 1:4. The hardness of the final product was seven times higher than that of beeswax, the cohesiveness of the final product was 1.3 times higher than that of beeswax and approximately one half of that of carnauba wax, and the melting point of the final product is 98°C. The Fourier transform Infrared spectroscopy showed that the amide groups were incorporated to form the amide products. In coating application, the results showed that the force of the final product coating cardboard was higher than that of beeswax and paraffin wax and less than that of carnauba wax. After 24 h soaking, the compression forces were decreased. HCO fatty acid wax can be an alternative wax for carnauba wax and beeswax in coating applications.

Adsorption of the Three-phase Emulsion on Various Solid Surfaces.

The present study investigates the adsorption of the three-phase emulsion on various solid/water interfaces. Vesicles can be used as emulsifiers in the three-phase emulsions and act as an independent phase unlike the surfactant used in conventional emulsions; therefore, it is expected that the three-phase emulsion formed by the adhesion of vesicles to the oil/water interface will adsorb on various solid/water interfaces. The cationic three-phase emulsion was prepared to encourage emulsion adsorption on negatively charged solid substrates in water. The emulsifier polyoxyethylene-(10) hydrogenated castor oil was rendered cationic by mixing with the surfactant cetyltrimethylammonium bromide and then used to prepare the cationic three-phase emulsion of hexadecane-in-water. Three solid substrates (silicon, glass, and copper) were dipped in the cationic emulsion and the emulsion was found to adsorb on the solid substrates while maintaining its structure. The amount of hexadecane adsorbed on the various surfaces was investigated by gas chromatography and found to increase with increasing hexadecane concentration in the emulsion and eventually plateaued just like molecular adsorption. The maximum surface coverage of the emulsion on the substrates was approximately 80%. However, even the equivalent nonionic three-phase emulsion was found to adsorb on the three solid surfaces. This was attributed to a novel mechanism of irreversible adhesion via the van der Waals attractive force.

Sustained release ivermectin-loaded solid lipid dispersion for subcutaneous delivery: in vitro and in vivo evaluation.

This work aimed to develop a sustained release solid dispersion of ivermectin (IVM-SD) in a lipid matrix (hydrogenated castor oil, HCO) for subcutaneous delivery. Solvent-melting technology was employed to prepare IVM-SDs using HCO. The physicochemical properties of the IVM-SDs were evaluated by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), and Fourier transform infrared spectroscopy (FTIR). The release of IVM from IVM-SDs was evaluated with HPLC in vitro. Pharmacokinetics of IVM was studied in rabbits following a single subcutaneous administration of IVM-SD formulations. The efficacy of IVM-SD against the ear mange mite was evaluated in rabbits. IVM was completely dispersed in HCO in an amorphous state at a drug:carrier ratio lower than 1:3. No chemical interactions between drug and carrier were found besides hydrogen bonding for the amorphous IVM-SDs. The amorphous IVM-SDs formulations exhibited a sustained release of IVM versus physical mixtures (PMs) of IVM and HCO. The drug release decreased as the drug:carrier ratios decreased, and the release kinetics of IVM were controlled via diffusion. Cytotoxicity of IVM-SD to MDCK cells was lower than native IVM. The IVM plasma concentration of SD1:3 remained above 1 ng/mL for 49 d. Higher AUC, MRT, and Tmax values were obtained at a SD1:3 relative to the IVM group. The IVM-SD improved almost 1.1-fold bioavailability of drug compared with IVM in rabbits. IVM-SD could provide longer persistence against rabbit's ear mites than a commercial IVM injection. This study shows that these solid lipid dispersions are a promising approach for the development of subcutaneous IVM formulations.

Predicting changes in aquatic toxicity of chemicals resulting from solvent or dispersant use as vehicle.

The influence of two vehicles (N,N-dimethylformamide [DMF] as solvent and polyoxyethylene hydrogenated castor oil [HCO-40] as a dispersant) on the acute toxicity of eight hydrophobic chemicals with a non-specific mode of action to Daphnia magna was investigated according to the OECD Guidelines for the Testing of Chemicals, No. 202. An increased 48-h EC50 value for D. magna or reduced toxicity resulting from the addition of HCO-40 to the test medium was observed for five of the eight chemicals examined. Each of eight chemicals was dissolved in water at a concentration of either 10 mg/L or 1.0 mg/L, with or without DMF or HCO-40. Silicone film as a model of a biological membrane was then immersed in each solution, and the concentration of each chemical in the water was monitored until equilibrium was reached for each test substance, after which the adsorbed amount of each chemical was determined. The amounts of p-pentylphenol and four other substances with log Pow (1-octanol/water partition coefficient) values greater than 3.4 adsorbed onto the silicone film decreased with increasing concentrations of HCO-40. However, 3-chloro-4-fluoronitrobenzene and two other substances with log Pow values less than 2.6 demonstrated no changes in adsorption with either increasing HCO-40 concentration or the addition of DMF. The reduced adsorption in the presence of a vehicle on the silicone film correlated closely with changes in toxicity. These results indicate that the methodology developed in this study enables the prediction of changes in toxicity resulting from the addition of vehicles to a test system.

New insights into eutectic cream skin penetration enhancement.

The manner in which the eutectic cream EMLA enhances the percutaneous penetration of lidocaine and prilocaine into human skin is still not fully understood. The purpose of this study was to investigate if the modification of drug aggregation played a role in the way EMLA facilitates delivery. Light scattering analysis of lidocaine alone in water gave a critical aggregation concentration (CAC) of 572 µM and a mean aggregate size of 58.8 nm. The analysis of prilocaine in identical conditions gave a CAC of 1177 µM and a mean aggregate size of 105.7 ± 24.8 nm. When the two drugs were mixed at their eutectic 1:1 ratio in water the CAC reduced to 165.8 µM and the aggregate size was 43.82 nm. This lidocaine-prilocaine interaction in water was further modified upon addition of polyoxyethylene hydrogenated castor oil, the surfactant in the EMLA aqueous phase, to produce aggregates of <20 nm. The physical characterisation data suggested that it was the EMLA cream's surfactant that modified the drug molecular interactions in the aqueous continuous phase and caused a 6 fold higher drug penetration through human epidermal tissue compared to the oil formulations tested in this study.

Reduced Food-Effect on Intestinal Absorption of Dronedarone by Self-microemulsifying Drug Delivery System (SMEDDS).

The oral absorption of dronedarone (DRN), a benzofuran derivative with anti-arrhythmic activity, is significantly affected by food intake. The absolute bioavailability of the marketed product (Multaq, Sanofi, U.S.) was about 4% without food, but increased to 15% when administered with a high fat meal. Therefore, to reduce the food-effect on the intestinal absorption of DRN, a novel self-microemulsifying drug delivery system (SMEDDS) was formulated and the comparative in vivo absorption studies with the marketed product were carried out using male beagle dogs either in the fasted or fed state. The SMEDDS consisted of the drug, Labrafil M 1944CS, and Kolliphor EL in a weight ratio of 1 : 1 : 2, rapidly formed a fine oil-in-water emulsion with a droplet size less than 50 nm. An in vivo absorption study revealed that the area-under-curve (AUC0-24 h) and maximal plasma concentration (Cmax) were 10.4-fold (p<0.05) and 8.6-fold (p<0.05) higher, respectively, after the marketed product was orally administered to beagles in the fed state when compared to those in the fasted state. This food-effect were remarkably alleviated by SMEDDS formulation, with AUC0-24 h and Cmax 2.9-fold (p<0.05) and 2.6-fold (p<0.05) higher in the fed state when compared to the fasted state, by facilitating intestinal absorption of DRN in the fasted state. The results of this study suggest that SMEDDS may decrease the differences in oral absorption of DRN between the prandial states, improving therapeutic efficacy as well as patient compliance.

An autopsy case of fatal repellent air freshener poisoning.

We describe a first fatal case of repellent air freshener ingestion. A 79-year-old Japanese man with Alzheimer-type senile dementia orally ingested repellent air freshener containing three surfactants: polyoxyethylene 9-lauryl ether, polyoxyethylene (40) hydrogenated castor oil, and lauric acid amidopropyl amine oxide (weight ratio of 1.3%). About 1h after the collapse, he was in cardiopulmonary arrest and subsequently died 10h after his arrival. The forensic autopsy performed 5.5h after death revealed the 380ml of stomach contents with a strong mint perfume identical to that of the repellent air freshener and the findings of acute death. Toxicologically, 9.1µg/ml and 558.2µg/ml of polyoxyethylene 9-lauryl ether were detected from the serum and stomach contents taken at autopsy. Generally, ingestion of anionic or non-ionic surfactants have been considered as safe. However, because the patient suffered from cardiac insufficiency with a low dose of repellent air freshener ingestion, medical staff members must evaluate the elderly patient for cardiac and circulatory problems regardless of the ingested dose. Not only medical and nursing staff members, but also families who are obliged to care for elderly persons must be vigilant to prevent accidental ingestion of toxic substances generally used in the household.

Safety Assessment of PEGylated oils as used in cosmetics.

PEGylated oil is a terminology used to describe cosmetic ingredients that are the etherification and esterification products of glycerides and fatty acids with ethylene oxide. The Cosmetic Ingredient Review Expert Panel (Panel) considered the safety of PEGylated oils, which function primarily as surfactants in cosmetic products. The Panel reviewed relevant animal and human data provided in this safety assessment and concluded that the 130 chemically related PEGylated oils were safe as cosmetic ingredients in the present practices of use and concentration when formulated to be nonirritating.

Extended duration local anesthetic agent in a rat paw model.

Encapsulated local anesthetics extend postoperative analgesic effect following site-directed nerve injection; potentially reducing postoperative complications. Our study aim was to investigate efficacy of our improved extended duration formulation - 15% bupivacaine in poly(DL-lactic acid co castor oil) 3:7 synthesized by ring opening polymerization. In vitro, around 70% of bupivacaine was released from the p(DLLA-CO) 3:7 after 10 days. A single injection of the optimal formulation of 15% bupivacaine-polymer or plain (0.5%) bupivacaine (control), was injected via a 22G needle beside the sciatic nerve of Sprague-Dawley rats under anesthesia; followed (in some animals) by a 1cm longitudinal incision through the skin and fascia of the paw area. Behavioral tests for sensory and motor block assessment were done using Hargreave's hot plate score, von Frey filaments and rearing count. The 15% bupivacaine formulation significantly prolonged sensory block duration up to at least 48 h. Following surgery, motor block was observed for 48 h following administration of bupivacaine-polymer formulation and rearing was reduced (returning to baseline after 48 h). No significant differences in mechanical nociceptive response were observed. The optimized bupivacaine-polymer formulation prolonged duration of local anesthesia effect in our animal model up to at least 48 h.

Influence of different additives and their concentrations on corneal toxicity and antimicrobial effect of benzalkonium chloride.

PURPOSE: The aim of this study was to examine the ophthalmic additives responsible for modulating acute corneal epithelial toxicity induced by benzalkonium chloride (BAC) and investigate the ability of polyoxyethylene hydrogenated castor oil 40 (HCO-40) and polysorbate 80 (PS-80) to reduce the corneal toxicity and antimicrobial effects of BAC. METHODS: Cytotoxicity of the additives, which included glycerin, polyvinyl alcohol, propylene glycol, polyethylene glycol, and PS-80, on rabbit corneal epithelial cells was examined using the cell proliferation assay in the presence and absence of 0.02% BAC. The corneal transepithelial electrical resistance change after a 60-second exposure to HCO-40 or PS-80 mixed with 0.02% BAC was measured in living rabbits. Corneal damage was examined using scanning electron microscopy. The antimicrobial activities of HCO-40 and PS-80 with 0.02% BAC against Staphylococcus aureus, Propionibacterium acnes, Pseudomonas aeruginosa, Escherichia coli, and Streptococcus pneumoniae were assessed. RESULTS: Of all the tested additives, only PS-80 could prevent the BAC-induced cytotoxicity. Corneal epithelial barrier function disorder caused by 0.02% BAC was significantly alleviated by either PS-80 or HCO-40 in a concentration-dependent manner. Scanning electron microscopy images showed an improvement of BAC-induced corneal epithelial toxicity after the addition of HCO-40 or PS-80. The antimicrobial effect of the BAC against P. aeruginosa, E. coli, and S. pneumoniae was reduced after adding HCO-40 or PS-80. CONCLUSIONS: HCO-40 and PS-80 reduce acute corneal toxicity and the antimicrobial effect of BAC. Possible interactions between BAC and other additives should be taken into consideration when evaluating the toxicity and antibacterial properties of BAC.

Polyurethane and polyurea nanoparticles based on polyoxyethylene castor oil derivative surfactant suitable for endovascular applications.

The design of new, safe and effective nanotherapeutic systems is an important challenge for the researchers in the nanotechnology area. This study describes the formation of biocompatible polyurethane and polyurea nanoparticles based on polyoxyethylene castor oil derivative surfactant formed from O/W nano-emulsions by polymerization at the droplet interfaces in systems composed by aqueous solution/Kolliphor(®) ELP/medium chain triglyceride suitable for intravenous administration. Initial nano-emulsions incorporating highly hydrophilic materials were prepared by the phase inversion composition (PIC) method. After polymerization, nanoparticles with a small particle diameter (25-55 nm) and low polydispersity index were obtained. Parameters such as concentration of monomer, O/S weight ratio as well as the polymerization temperature were crucial to achieve a correct formation of these nanoparticles. Moreover, FT-IR studies showed the full conversion of the monomer to polyurethane and polyurea polymers. Likewise the involvement of the surfactant in the polymerization process through their nucleophilic groups to form the polymeric matrix was demonstrated. This could mean a first step in the development of biocompatible systems formulated with polyoxyethylene castor oil derivative surfactants. In addition, haemolysis and cell viability assays evidenced the good biocompatibility of KELP polyurethane and polyurea nanoparticles thus indicating the potential of these nanosystems as promising drug carriers.

Bioequivalence of Liposome-Entrapped Paclitaxel Easy-To-Use (LEP-ETU) formulation and paclitaxel in polyethoxylated castor oil: a randomized, two-period crossover study in patients with advanced cancer.

BACKGROUND: Preclinical studies comparing paclitaxel formulated with polyethoxylated castor oil with the sonicated formulation of liposome-entrapped paclitaxel (LEP) have demonstrated that LEP was associated with reduced toxicity while maintaining similar efficacy. Preliminary studies on the pharmacokinetics in patients support earlier preclinical data, which suggested that the LEP Easy-to-Use (LEP-ETU) formulation and paclitaxel formulated with castor oil may have comparable pharmacokinetic properties. OBJECTIVES: Our objectives were: (1) to determine bioequivalence of paclitaxel pharmaceutically formulated as LEP-ETU (test) and paclitaxel formulated with castor oil (reference); and (2) to assess the tolerability of LEP-ETU following intravenous administration. METHODS: Patients with advanced cancer were studied in a randomized, 2-period crossover bioequivalence study. Patients received paclitaxel 175 mg/m(2) administered as an intravenous infusion over 180 minutes, either as a single-treatment cycle of the test formulation followed by a single-treatment cycle of the reference formulation, or vice versa. RESULTS: Thirty-two of 58 patients were evaluable and were included in the analysis for bioequivalence. Mean total paclitaxel Cmax values for the test and reference formulations were 4955.0 and 5108.8 ng/mL, respectively. Corresponding AUC0-∞ values were 15,853.8 and 18,550.8 ng·h/mL, respectively. Treatment ratios of the geometric means were 97% (90% CI, 91%-103%) for Cmax and 84% (90% CI, 80%-90%) for AUC0-∞. These results met the required 80% to 125% bioequivalence criteria. The most frequently reported adverse events after LEP-ETU administration were fatigue, alopecia, and myalgia. CONCLUSION: At the studied dose regimen, LEP-ETU showed bioequivalence with paclitaxel formulated with polyethoxylated castor oil.

Preparation methods for monodispersed garlic oil microspheres in water using the microemulsion technique and their potential as antimicrobials.

Garlic oil is considered as a natural broad-spectrum antibiotic because of its well-known antimicrobial activity. However, the characteristics of easy volatility and poor aqueous solubility limit the application of garlic oil in industry. The purpose of the present work is to develop and evaluate an oil-free microemulsion by loading garlic oil in microemulsion system. Microemulsions were prepared with ethoxylated hydrogenated castor (Cremophor RH40) as surfactant, n-butanol (or ethanol) as cosurfactant, oleic acid-containing garlic oil as oil phase, and ultrapure water as water phase. The effects of the ratio of surfactant to cosurfactant and different oil concentration on the area of oil-in-water (O/W) microemulsion region in pseudoternary phase diagrams were investigated. The particle size and garlic oil encapsulation efficiency of the formed microemulsions with different formulations were also investigated. In addition, the antimicrobial activity in vitro against Escherichia coli and Staphylococcus aureus was assessed. The experimental results show that a stable microemulsion region can be obtained when the mass ratio of surfactant to cosurfactant is, respectively, 1:1, 2:1, and 3:1. Especially, when the mixture surfactants of RH40/n-butanol 2/1 (w/w) is used in the microemulsion formulation, the area of O/W microemulsion region is 0.089 with the particle size 13.29 to 13.85 nm and garlic oil encapsulation efficiency 99.5%. The prepared microemulsion solution exhibits remarkable antibacterial activity against S. aureus.

Cost-utility analysis of nanoparticle albumin-bound paclitaxel versus paclitaxel in monotherapy in pretreated metastatic breast cancer in Spain.

AIM: The COSTABRAX study evaluated the cost-effectiveness of nanoparticle albumin-bound paclitaxel (nab-paclitaxel) versus polyethylated castor oil-based standard paclitaxel (sb-paclitaxel) in the treatment of patients with previously treated metastatic breast cancer in Spain. MATERIALS & METHODS: Efficacy data were obtained from the CA012 trial (nab-paclitaxel administered every 3 weeks [q3w] and sb-paclitaxel q3w) and indirect comparison (sb-paclitaxel administered weekly), and were modeled to a time horizon of 5 years using a Markov model. The analysis was performed from the National Health Service perspective. Use of resources and key assumptions of the model were validated by a panel of 22 local oncologists. RESULTS: Compared with sb-paclitaxel q3w, nab-paclitaxel q3w was cost effective, with a cost per life year gained of €11,088 and a cost per quality-adjusted life year of €17,808. Compared with sb-paclitaxel administered weekly, it showed savings of €711 per patient. CONCLUSION: The COSTABRAX study showed that nab-paclitaxel q3w is a cost-effective alternative compared with sb-paclitaxel q3w and a cost-saving alternative to sb-paclitaxel administered weekly in Spain.

Hypersensitivity reaction studies of a polyethoxylated castor oil-free, liposome-based alternative paclitaxel formulation.

The commercial drug paclitaxel (Taxol) may introduce hypersensitivity reactions associated with the polyethoxylated castor oil-ethanol solvent. To overcome these problems, we developed a polyethoxylated castor oil-free, liposome-based alternative paclitaxel formulation, known as Lipusu. In this study, we performed in vitro and in vivo experiments to compare the safety profiles of Lipusu and Taxol, with special regard to hypersensitivity reactions. First, Swiss mice were used to determine the lethal dosages, and then to evaluate hypersensitivity reactions, followed by histopathological examination and enzyme-linked immunosorbent assays (ELISAs) of serum SC5b-9 and lung histamine. Additionally, healthy human serum was used to analyze in vitro complement activation. Finally, an MTT assay was used to determine the in vitro anti-proliferation activity. Our data clearly showed that Lipusu displayed a much higher safety margin and did not induce hypersensitivity or hypersensitivity-related lung lesions, which may be associated with the fact that Lipusu did not activate complement or increase histamine release in vivo. Moreover, Lipusu did not promote complement activation in healthy human serum in vitro, and demonstrated anti-proliferative activity against human cancer cells, similar to that of Taxol. Therefore, the improved formulation of paclitaxel, which exhibited a much better safety profile and comparable cytotoxic activity to Taxol, may bring a number of benefits to cancer patients.

Novel Th1-biased adjuvant, SPO1, enhances mucosal and systemic immunogenicity of vaccines administered intranasally in mice.

Oil-in-water emulsions are potent human adjuvants commonly used in effective pandemic influenza vaccines; however, such emulsions that can induce both Th1-biased systemic immune responses and strong mucosal immune responses via an easy method of administration are lacking. To address this need for new adjuvants, we developed a novel oil/water emulsion, SPO1, which allows convenient mucosal immunization via an intranasal spray as well as by parenteral routes. Our report shows that SPO1 was able to boost up immunological resistance by inducing effective mucosal and serum antibodies, and the immune response was polarized to a Th1 pattern, as demonstrated by high IgG2α antibody levels and interferon-gamma production by splenocytes from intranasally (i.n.) immunized mice. Up-regulation of co-stimulatory and antigen-presenting molecules on dendritic cells was also observed in vivo after i.n. immunization, suggesting a possible mechanism for the adjuvant effects of SPO1. Another explanation may simply be a depot of antigen at the immunization site, as evidenced by in vivo imaging of i.n. immunized mice. In conclusion, our results demonstrate that a novel oil/water emulsion, SPO1, is a potent Th1 adjuvant for use in influenza and other vaccines, as it induces strong mucosal and systemic immune responses.

Solid lipid nanoparticle suspension enhanced the therapeutic efficacy of praziquantel against tapeworm.

Hydatid disease caused by tapeworm is an increasing public health and socioeconomic concern. In order to enhance the therapeutic efficacy of praziquantel (PZQ) against tapeworm, PZQ-loaded hydrogenated castor oil solid lipid nanoparticle (PZQ-HCO-SLN) suspension was prepared by a hot homogenization and ultrasonication method. The stability of the suspension at 4°C and room temperature was evaluated by the physicochemical characteristics of the nanoparticles and in-vitro release pattern of the suspension. Pharmacokinetics was studied after subcutaneous administration of the suspension in dogs. The therapeutic effect of the novel formulation was evaluated in dogs naturally infected with Echinococcus granulosus. The results showed that the drug recovery of the suspension was 97.59% ± 7.56%. Nanoparticle diameter, polydispersivity index, and zeta potential were 263.00 ± 11.15 nm, 0.34 ± 0.06, and -11.57 ± 1.12 mV, respectively and showed no significant changes after 4 months of storage at both 4°C and room temperature. The stored suspensions displayed similar in-vitro release patterns as that of the newly prepared one. SLNs increased the bioavailability of PZQ 5.67-fold and extended the mean residence time of the drug from 56.71 to 280.38 hours. Single subcutaneous administration of PZQ-HCO-SLN suspension obtained enhanced therapeutic efficacy against tapeworm in infected dogs. At the dose of 5 mg/kg, the stool-ova reduction and negative conversion rates and tapeworm removal rate of the suspension were 100%, while the native PZQ were 91.55%, 87.5%, and 66.7%. When the dose reduced to 0.5 mg/kg, the native drug showed no effect, but the suspension still got the same therapeutic efficacy as that of the 5 mg/kg native PZQ. These results demonstrate that the PZQ-HCO-SLN suspension is a promising formulation to enhance the therapeutic efficacy of PZQ.

Detailed molecular characterization of castor oil ethoxylates by liquid chromatography multistage mass spectrometry.

The molecular characterization of castor oil ethoxylates (CASEOs) was studied by reverse-phase liquid chromatography (RPLC) mass spectrometry (MS) and multistage mass spectrometry (MS(n)). The developed RPLC method allowed the separation of the various CASEO components, and especially, the baseline separation of multiple nominal isobars (same nominal mass) and isomers (same exact mass). MS and MS(n) were used for the determination and structure elucidation of various structures and for the discrimination of the isobars and isomers. Different ionization techniques and adduct ions were also tested for optimization of the MS detection and the MS(n) fragmentation. A unique fragmentation pathway of ricinoleic acid is proposed, which can be used as a marker of the polymerization process and the topology of ethoxylation in the CASEO. In addition, characteristic neutral losses of ricinoleic acid reveal its (terminal or internal) position in the molecule.