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Technical Information
Lutrol® L and
April 2010
Supersedes issue dated February 2010
Lutrol F-Grades
03_100102e-03/Page 1 of 8
Poloxamers Ph. Eur., Poloxamer USP/NF
Poloxamers for Pharmaceutical Use
Pharma Ingredients
& Services
Chemical nature
The Lutrol L and F-block copolymers are synthetic copolymers of ethylene oxide and propylene oxide represented by the following chemical structure: Wherein a and b blocks have the following values: Poloxamer
Description
Lutrol L 44 is a milky white paste or liquid. The product contains d,l-alpha toco- The Lutrol F-grades are white, coarse-grained powders with a waxy consistency. They contain an appropriate quantity of the antioxidant BHT.

PRD-Nos.
Specifications
See separate document: “Standard Specification (not for regulatory purposes)“ available via BASF’s WorldAccount: https://worldaccount.basf.com (registered US Drug Master File
BASF maintains a Drug Master File for Poloxamers at the FDA and is familiar with supplying information to the FDA to assist customers in obtaining FDA authorizations.
Further Typical Properties
Solid, prill Solid, prill Solid, prill Solid, prill 50 max. 100 max. 100 max. 80 max. 120 max. 50 – 125 50 – 125 50 – 125 50 – 125 >100 °C >100 °C >100 °C >100 °C The poloxamers are not only readily soluble in water but also in polar and non- The average particle size of the prilled Lutrol F-grades is around 1000 µm. Apart from the prilled products some microprilled poloxamers were developed for specific formulation needs. The microprilled products Lµtrol micro 68 (micro- prilled Poloxamer 188) and Lµtrol micro 127 (microprilled poloxamer 407) were microprilled to an average particle size of approximately 50 µm. Both products For further information on the micropril ed Lµtrol grades please refer to the individual Technical Information sheets.
Product Properties and
When dispersed in the liquid at low concentrations, Poloxamers exist individual y as fields of application
monomolecular micel es. When the concentration of the poloxamers in the system increases, this results in the formation of multimolecular aggregates. Polypropylene oxide (PPO) usual y forms central hydrophobic cores wherein methyl groups interact via Van der Waals forces with the substance undergoing solubilization. However, water solubility is believed to be due to the polyethylene oxide (PEO) block by hydrogen bonding interactions of ether oxygen with water molecules. Due to these interactions, poloxamers are readily soluble in polar and non-polar organic solvents which al ows a wide range of dosage forms to be formulated with these Excipients.
Lutrol L 44 is the only monographed poloxamer that is liquid at room temperature. It is applied for liquid filled soft gel capsules as a dispersion medium for APIs.
Lutrol F 68 and Lutrol F 87 are used as wetting agents, as emulsifiers and solubilizers, Lutrol F 68 has been formulated in liquid dosage forms for parenteral use. Lutrol F 68 and Lutrol F 87 are suitable to prepare solid dispersions and to improve the solubility, absorption and bioavailability of low-solubility actives in solid oral dosage forms. The corresponding dosage forms are usual y processed by melting or granulation. In addition, Lutrol F 68 can also act as a co-emulsifier Aqueous solutions of Lutrol F 68 have Newtonian flow properties that change to non-Newtonian behavior at higher concentrations. Aqueous solutions containing more than 20% Lutrol F 68 are thermoreversible, i.e. the minimum viscosity is between 15 and 60 °C and the maximum viscosity between 75 and 80 °C (see Repeated heating and cooling does not affect this property.
The gelling properties of individual poloxamers depend on their molecular weight. Those with higher molecular weights show a pronounced gelling effect at lower concentrations. Thus Lutrol F 108 and Lutrol F 127 are the preferred poloxamers for gels. At lower concentrations, the poloxamers can be used to modulate the viscosity of liquid formulations.
Fig. 1: Dynamic viscosity of aqueous solutions of Lutrol F 68 as a function of temperature using a HAAKE Rheostress 6000 (RS) with a plate/plate configuration PP60Ti with 1,0mm distance and an amplitude of 0.010rad and a frequency of Lutrol F 108 and Lutrol F 127 are used primarily as thickening agents and gel formers, but also as co-emulsifiers and consistency enhancers in creams and liquid emulsions. Lutrol F 127 is also used as a solubilizer for certain active sub- stances such as nifedipine, naproxen and fenticonazole as well as for essential oils in pharmaceutical formulations.
Moreover, Lutrol F 127 is suitable for the formulation of active substances that show reduced solubility as well as chemical stability as a result of neutralization of gel formulations. Owing to its ability to affect viscosity, Lutrol F 108 and Lutrol F 127 are suitable as stabilizers for topically administered suspensions. Lutrol F 127 is also used in toothpastes, gargles and mouthwashes.
In solid oral dosage forms the microprilled products Lµtrol micro 68 and Lµtrol micro 127 are successfully formulated because the very coarse prilled products are not very suitable as content uniformity of the solid oral dosage form will be Thermoreversible gelation
Lutrol F 108 and Lutrol F 127 show the characteristic property of thermoreversible gelation. The reversible thermal behavior of these two poloxamers in case of dilute as well as concentrated solutions was studied extensively. Generally, this type of behavior is observed in aqueous solutions of concentration range 16 – 30% w/w. They are liquid when refrigerated (4 – 5 °C) or heated to temperatures exceeding 70 °C but turn into gel form when at room temperature. They exhibit maximum viscosity in the range of 30 – 60 °C.
The gels thus formed are reversible again on cooling or heating.
Preparation of gels
Gels may generally be prepared by two methods: Lutrol F 108 or Lutrol F 127 are completely dissolved in water at room temperature or water pre-cooled to approx. 5 °C. Active substances that are insoluble in water are dissolved in ethanol, isopropanol or propylene glycol and mixed with the aqueous phase containing the poloxamer at 5 °C to form a homogeneous mass. Lutrol F 127 is dissolved in water at approx. 70 °C. Active substances that are insoluble in water are dissolved in ethanol, isopropanol or propylene glycol at 70 °C and mixed with the warm aqueous phase to form a homogeneous mass. The gel forms when the solution cools to room temperature. Both methods of preparation will generally yield gels with comparable properties.
Adding Lutrol F 108 or Lutrol F 127 to the hot aqueous phase to fast the formation of lumps may happen. These wil only dissolve after standing for several hours. Any loss of solvent must be replaced, otherwise a thixotropic ef ect may be observed. The “cold process” for the preparation of gels, particularly if active substances sensitive to heat are formulated is highly recommended. In order to prevent the gel to entrap air bubbles, a vacuum should be applied to the formulation before Gels using identical concentrations of Lutrol F 127 but being prepared by either of the two methods described above did not reveal differences in their viscosity Fig. 2: Viscosity of aqueous Lutrol F 127 prepared either by the hot (orange curve) or cold (black curve) process. Viscosity determination using a HAAKE Rotovisco 1 rotational viscometer with a double gap concentric cylinder measuring geometry The following figure shows the influence of increasing concentrations of Lutrol F 127 on sol-gel transition temperature and on the gel strength. The determination is performed using an oscil ating plate/plate configuration to avoid detrimental effects of higher shear rates on the gel strength. Fig. 3: Complex dynamic viscosity of aqueous Lutrol F 127-gels as a function of temperature. Viscosity determation was performed using a HAAKE Rheostress 6000 with a plate/plate configuration PP60Ti with an amplitude of 0.010 and a Figure 4 shows the influence of the shear rate on the viscosity of a gel formulated with 20% Lutrol F 127. The dynamic viscosity was determined using a HAAKE Rotovisco 1 (RV) with a double gap concentric cylinder measuring geometry DG43 with a cup. For the complex dynamic viscosity a HAAKE Rheostress 6000 (RS) with a plate/plate configuration PP60Ti with 1.0 mm distance and an amplitude of 0.010 rad and a frequency of 1000/s was applied Fig. 4: Influence of the shear rate on the gel strength of a 20% Lutrol F 127-gel The dynamic viscosity of Lutrol F 108 and Lutrol F 127 gels may be affected by the addition of electrolytes, moisturizers, alcohols and surfactants. Figure 5 demon- strate the influence of sodium chloride and potassium chloride in a 20% Lutrol F 127-gel. The addition of electrolytes at concentrations of around 1% increases the viscosity with little or no impact on the sol-gel transition temperature. Higher concentrations demonstrate a reduced gel ing temperature with increased dynamic viscosity readings. In contrast to this, ethanol increases the gel formation temperature. The use of anionic surfactants may inhibit gel formation, even at Lutrol F 127 con- centrations exceeding 20%. This is true, for example, for sodium lauryl sulphate at concentrations above 2%. Low pH values affect both the sol-gel transition 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 Fig. 5: Pour point of 25% aqueous Lutrol F 127 gels at different NaCl – or KCl – Examples for Gel Formulations
Topically applied gels formulated with Lutrol F 108 and Lutrol F 127 feel tacky to a certain extent. This tackiness can be minimized when the gels are formulated with 1% to 2% of either propylene carbonate or isopropyl myristate.
Lutrol F 127 gel
Active substance
Description: clear, stable, colorless gel.
Lutrol F 108 gel
Active substance
Description: clear, stable, colorless gel.
Lutrol F 127/F 68 gel
Active substance
Description: clear, stable, colorless gel Article numbers & Packaging
50143751 55116438 56494120 50149504 55097782 54779199 51633115 50102804 50118158 51632903 Stability and storage
The retest period for the Lutrol L and Lutrol F-grades is two years when stored in properly sealed containers at temperatures below 25 °C. Handling and Disposal
Please refer to the individual Material Safety Data Sheet (MSDS) for instructions on safe and proper handling and disposal.
For proper product handling and sampling homogenization of the drum content is necessary (thoroughly mixing at room temperature). This document, or any answers or information provided herein by BASF, does not constitute a legal y binding obligation of BASF. While the descriptions, designs, data and information contained herein are presented in good faith and believed to be accurate, it is provided for your guidance only. Because many factors may affect processing or application/use, we recommend that you make tests to determine the suitability of a product for your particular purpose prior to use. It does not relieve our customers from the obligation to perform a ful inspection of the products upon delivery or any other obligation. NO WARRANTIES OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE MADE REGARDING PRODUCTS DESCRIBED OR DESIGNS, DATA OR INFORMATION SET FORTH, OR THAT THE PRODUCTS, DESIGNS, DATA OR INFORMATION MAY BE USED WITHOUT INFRINGING THE INTELLECTUAL PROPERTY RIGHTS OF OTHERS. IN NO CASE SHALL THE DESCRIPTIONS, INFORMATION, DATA OR DESIGNS PROVIDED BE CONSIDERED A PART OF OUR TERMS AND CONDITIONS OF SALE. BASF SE - Care Chemicals Division - Pharma Ingredients & Services - 67117 Limburgerhof - www.pharma-ingredients.basf.com

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