Kolliphor^® ELP is the industry standard pharmaceutical surfactant used primarily as a solubilizer and emulsifier. Kolliphor^® ELP is a white to yellowish paste or cloudy liquid. It is a non-ionic solubilizer made by reacting castor oil with ethylene oxide in a molar ratio of 1:35. This is followed by a purification process. Kolliphor^® ELP forms clear solutions in water and also dissolves in a wide range of organic solvents, such as ethanol, n-propanol, isopropanol, ethyl acetate, chloroform, carbon tetrachloride, trichloroethylene, toluene and xylene.

Benefits
    Highly purified Kolliphor^® EL grade (Polyoxyl-35-castor oil)
    Endotoxin controlled
    Excellent compatibility with other ingredients
    Purified solubilizer for paclitaxel formulations
    Especially suitable for formulations containing extremely sensitive APIs
    Compliant with Ph. Eur. and USP-NF
    Also stabilizes biologic drug formulations

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TECHNICAL INFORMATION

Description
Kolliphor^® ELP is a solubilizer, emulsifier and primary surfactant used in a multitude of pharmaceutical formulations, with the primary indication for sensitive APIs and parenteral use.

Kolliphor^® ELP, a purified grade of Kolliphor^® EL was specifically developed for sensitive active ingredients, as the higher purity was found to improve their stability.

Unlike Kolliphor^® EL, Kolliphor^® ELP is a white to yellowish paste or cloudy liquid. It exhibits tighter specifications with regard to water content, potassium ions and free fatty acids, in particular, ricinoleic, oleic and palmitic acids.

Upon heating, the last solid constituents melt at approximately 26°C to yield a clear oily liquid with a weak but characteristic odor.

Structural formula
Kolliphor^® ELP is a nonionic solubilizer and emulsifying agent obtained by reacting castor oil with ethylene oxide in a molar ratio of 1:35.

The main constituent of Kolliphor^® ELP is glycerol polyethylene glycol ricinoleate, which, together with fatty esters of polyethylene glycol, this forms the hydrophobic part of the product. The hydrophilic part consists of free polyethylene glycols and ethoxylated glycerol.

Solubility
Kolliphor^® ELP forms clear solutions in water. It is also soluble in many organic solvents, e.g. ethyl alcohol, n-propyl alcohol, isopropyl alcohol, ethyl acetate, chloroform, carbon tetrachloride, trichloroethylene, toluene and xylene.

In contrast to anionic emulsifying agents, Kolliphor^® ELP becomes less soluble in water at higher temperatures. Thus, aqueous solutions become turbid at a certain temperature.

Kolliphor^® ELP is miscible with all the other Kolliphor grades and, on heating, also with fatty acids, fatty alcohols and certain animal and vegetable oils. It is thus miscible with oleic and stearic acids, dodecyl and octa-decyl alcohols, castor oil, and a number of lipid-soluble substances.

Critical micelle concentration : The critical micelle concentration (CMC) is 0.02% w/w at +37°C.

Dispensing and Sterilization
It is recommended that Kolliphor^® ELP be heated to between 50°C and 60°C and lightly agitated prior to use. Kolliphor^® ELP exhibits complex melting behavior, and phase separation is known to occur depending on the shipping and storage conditions.
This is easily overcome via melting and light mixing.

In order to ensure product stability during reheating, heat cycling was performed on Kolliphor^® ELP. Commercial material was heated to 60°C and held for 24 hours, then cooled and held at room temperature for a further 24 hours; this was repeated 20 times in total. The results of this stress test on the stability indicating parameters of Kolliphor^® ELP are shown below, no significant deviation was noted.

Furthermore, as Kolliphor^® ELP is often used in formulations that are subject to sterilization (e.g. parenterals), a stress test using a single autoclave cycle (121°C, 20 min.) and sterile filtration (0.20 µm) were used to study 20% (w/w) solutions of Kolliphor^® ELP; the consolidated results on stability indicating parameters are shown below.

Package size : 60 kg steel drum.