Sustainable Alternatives to Petroleum-Derived Excipients in Pharmaceutical Oil-in-Water Creams

Recently, vast efforts towards sustainability have been made in the pharmaceutical industry. In conventional oil-in-water (O/W) cream formulations, various petroleum-based excipients, namely mineral oil and petrolatum, are commonly used. Natural or synthetic excipients, derived from vegetable sources, were explored as alternatives to petroleum-based excipients in prototype topical creams, with 1% (w/w) lidocaine. A conventional cream comprised of petroleum-derived excipients was compared to creams containing sustainable excipients in terms of key quality and performance attributes, physicochemical properties, and formulation performance.

The petrolatum-based control formulation had the highest viscosity of 248.0 Pa·s, a melting point of 42.7°C, a low separation index at 25°C of 0.031, and an IVRT flux of 52.9 µg/cm²/h. Formulation SUS-4 was the least viscous formulation at 86.9 Pa·s, had the lowest melting point of 33.6°C, the highest separation index of 0.120, and the highest IVRT flux of 139.4 µg/cm²/h. Alternatively, SUS-5 had a higher viscosity of 131.3 Pa·s, a melting point of 43.6°C, a low separation index of 0.046, and the lowest IVRT flux of 25.2 µg/cm²/h. The cumulative drug permeation after 12 h from SUS-4, SUS-5, and the control were 126.2 µg/cm², 113.8 µg/cm², and 108.1 µg/cm², respectively.

The composition of the oil-in-water creams had influence on physicochemical properties and drug release; however, skin permeation was not impacted. Sustainable natural or synthetic excipients in topical cream formulations were found to be suitable alternatives to petroleum-based excipients with comparable key quality attributes and performance attributes and should be considered during formulation development.