Compendium of the most significant studies with reference to properties, intake, effects.

Rachmawati H, Novel MA, Ayu S, Berlian G, Tandrasasmita OM, Tjandrawinata RR, Anggadiredja K. The In Vitro-In Vivo Safety Confirmation of PEG-40 Hydrogenated Castor Oil as a Surfactant for Oral Nanoemulsion Formulation. Sci Pharm. 2017 Mar 31;85(2):18. doi: 10.3390/scipharm85020018. 

Abstract. Evaluation on the safety use of high concentration of polyoxyl 40 (PEG-40) hydrogenated castor oil as a surfactant for oral nanoemulsion was performed in Webster mice. As previously reported, nearly 20% of PEG-40 hydrogenated castor oil was used to emulsify the glyceryl monooleate (GMO) as an oil to the aqueous phase. Thermodynamically stable and spontaneous nanoemulsion was formed by the presence of co-surfactant polyethylene glycol 400 (PEG-400). Standard parameters were analyzed for nanoemulsion including particle size and particle size distribution, the surface charge of nanoemulsion, and morphology. To ensure the safety of this nanoemulsion, several cell lines were used for cytotoxicity study. In addition, 5000 mg/kg body weight (BW) of the blank nanoemulsion was given orally to Webster mice once a day for 14 days. Several parameters such as gross anatomy, body weight, and main organs histopathology were observed. In particular, by considering the in vivo data, it is suggested that nanoemulsion composed with a high amount of PEG-40 hydrogenated castor oil is acceptable for oral delivery of active compounds.

Djekic L, Ibric S, Primorac M. The application of artificial neural networks in the prediction of microemulsion phase boundaries in PEG-8 caprylic/capric glycerides based systems. Int J Pharm. 2008 Sep 1;361(1-2):41-6. doi: 10.1016/j.ijpharm.2008.05.002.

Abstract. The objective of this study was to develop artificial neural network (ANN) model suitable to predict successfully the borders of the microemulsion region in the quaternary system PEG-8 caprylic/capric glycerides (Labrasol)/cosurfactant/isopropyl myristate/water, in order to minimise experimental effort. In our preliminary investigations of phase behaviour, two cosurfactants were used, PEG-40 hydrogenated castor oil (Cremophor) RH 40) and polyglyceryl-6 isostearate (Plurol Isostearique). Microemulsion existance area in pseudo-ternary phase diagrams was determined using titration method at constant: (a) oil-to-water ratio (alpha=50%, w/w); (b) surfactant-to-cosurfactant ratio (Km) 4:6; (c) Km 5:5; or (d) Km 6:4. It was found that the phase behaviour of systems involving polyoxyethylene type of cosurfactant depends significantly on oil-to-surfactant/cosurfactant mixture mass ratio (O/SCoS) but it is Km-independent. The formation of microemulsions in Labrasol/polyglyceryl-6 isostearate based systems was a complex function of Km and O/SCoS and there was employed a Generalized Regression Neural Network (GRNN) with four layers as a predictive mathematical model, using data obtained from the phase behaviour study (the surfactant concentration in surfactant/cosurfactant mixture (S, %, w/w), the oil concentration in the mixture with tensides (O, %, w/w) as two input variables, and the water solubilization limit (W(max), %, w/w) as output data). After network training, six independent pairs of input/output data were used for network testing. The resulting GRNN was tested statistically and found to be of quality predictive power. This results confirmed that the trained GRNN could be effective in predicting the size of the microemulsion area providing valuable tool in formulation of this type of colloidal vehicles.

Deyab MA. Utilization of a nonionic surfactant for improved corrosion resistance of carbon steel in simulated fuel-grade ethanol. RSC Adv. 2018 Jun 7;8(37):20996-21001. doi: 10.1039/c8ra02936a. 

Abstract. In this study, a nonionic surfactant (PEG-40 hydrogenated castor oil, Abbrev. PEG-40 HCO) was used to improve the corrosion resistance of carbon steel in simulated fuel-grade ethanol (SFGE). The studies were conducted using cyclic voltammetry (CV) and potentiodynamic polarization techniques and complemented by scanning electron microscopy (SEM) investigations. The presence of water and chloride ions in SFGE strongly influences the electrochemical behavior of carbon steel. Polarization curves indicate that PEG-40 HCO has good inhibition efficiency and behaves as a mixed inhibitor. The inhibition efficiency increases with the concentration of PEG-40 HCO within the range of 20 to 100 ppm, reaching a maximum value of 93.8%. The adsorption of PEG-40 HCO obeys the Langmuir adsorption isotherm. Quantum chemical calculations were evaluated to confirm experimental results. This journal is © The Royal Society of Chemistry.

Hua L, Weisan P, Jiayu L, Hongfei L. Preparation and evaluation of microemulsion of vinpocetine for transdermal delivery. Pharmazie. 2004 Apr;59(4):274-8. 

Abstract. Poorly soluble vinpocetine was selected as the model drug to prepare a microemulsion in order to increase solubility and in vitro transdermal delivery of the drug. Oleic acid was chosen as the oil phase due to its excellent solubilizing capacity. PEG-40 hydrogenated castor oil (Cremophor RH40) was employed as a surfactant (S) and purified diethylene glycol monoethyl ether (Transcutol P) was used as a cosurfactant (CoS). The effects of diverse types of oil, different weight ratios of surfactant to cosurfactant (S/CoS) on the solubility and permeation rate of vinpocetine were investigated. The optimized microemulsion consisted of 1% vinpocetine, 4% oleic acid, 20% Cremophor RH40, 10% Transcutol P and 65% distilled water (w/w), in which drug solubility was about 2,100 fold compared to that in water and the apparent permeation rate across the excised rat skin was 15.0 +/- 2.5 microg/cm2/h. Finally the physicochemical properties of the optimized microemulsion including pH, viscosity, refractive index, conductivity and particle size distribution were examined, which showed stable behavior after more than 12 months at ambient temperature. The irritation study showed that optimized microemulsion was a safe transdermal delivery system.

Milović M, Djuriš J, Djekić L, Vasiljević D, Ibrić S. Characterization and evaluation of solid self-microemulsifying drug delivery systems with porous carriers as systems for improved carbamazepine release. Int J Pharm. 2012 Oct 15;436(1-2):58-65. doi: 10.1016/j.ijpharm.2012.06.032.

Abstract. The purpose of this study was to investigate solid self-microemulsifying drug delivery system (SSMEDDS), as potential delivery system for poorly water soluble drug carbamazepine (CBZ)....Copyright © 2012 Elsevier B.V.