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Excipients for Drug Formulation
Viscosity Enhancement
BASF offers a variety of products that enhance the viscosity of your topical formulation.
In creams and lotions the stiffness or viscosity of the formulation plays an important role in (1) the proper extrusion of the product from the primary package, (2) the handling of the formulation during application, (3) the stabilization of the dispersed phase (e.g. oil, water, solids, etc.) in the primary package and (4) maintaining the homogeneous distribution of the API in the package during shelf life.
Benefits
- Variety of excipients that enhance the viscosity of your formulation
- Extensive expertise and understanding of topical products
- Meets the highest regulatory and quality requirements
- Prooven mildness and sensory performance of BASF excipients
Viscosity enhancement in topical formulations
Microstructures
Typically the desired viscosity or consistency of creams and lotions is built through the addition of solid fatty alcohols, fatty acids, fatty esters and glycerides (Sometimes these materials are called “waxes”. Without the inclusion of these excipients the emulsion formulation will remain watery and difficult to handle. When mixed with emulsifiers and water these materials organize into microstructures (e.g. lamellar phases, gel phases, crystalline phases, etc.) that extend through the continuous water phase and build stiffness and consistency.
Control of rheological properties
The rheological properties of a cream can be controlled by the choice of wax that is utilized, the amount of the wax and the wax and emulsifier ratio.
Combinations of cetyl and stearyl alcohol for a a soft cream
One of the most commonly used waxes for topical dermatological creams is cetostearyl alcohol, which is a mixture of cetyl and stearyl alcohols. Combinations of cetyl and stearyl alcohol tend to be more stable than cetyl or stearyl alcohol alone. BASF offers Kolliwax® CSA 50 and Kolliwax® CSA 70, which differ only in the ratio of cetyl and stearyl alcohol. The formulator also has the option to customize ratios or use cetyl and stearyl alcohol alone by using our Kolliwax® CA and Kolliwax® SA. Kolliwax® MA (myristyl alcohol) can be used to create a soft, rapidly melting and fast absorbing cream.
Other alternatives
Consistency and stiffness can also be managed by using stearic acid (Kolliwax® S) and glyceryl monostearate or mono- and di- glycerides C16-C18 (Kolliwax® GMS II), as well as Kolliwax® HCO (hydrogenated castor oil).
Learn more about our viscosity enhancement solutions for topical formulations
In focus
Microstructure in topical drug development
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1Learn more about the importance of microstructure in topical drug development and how BASF is playing an integral role in this hot industry.
In focus
Topical Drug Formulation Tips and Techniques
Podcast (on demand)
The role of semisolid microstructure in topical formulation performance and functionality
Webinar (on demand)
Controlling the physical properties and performance of semi-solid formulations
