Fatty acids lipid formulations

Wang, M.Y., Yang, Y.Y, and Heng, P.W. (2004). Role of solvent in interactions between fatty acids-based formulations and lipids in porcine stratum corneum, J. Controlled... 

Drug A is a large, peptide-like molecule (MW 700 g/mol) and is highly lipophilic and poorly water soluble. It is a BCS Class II drugs. Its oral bioavailability in capsules and conventional tablet formulations is low, yielding practically undetected blood levels. A novel lipid formulation containing a solvent, a high HLB nonionic surfactant, and a fatty acid were developed with sufLcient oral bioavailability for use in the clinic. 

As mentioned, hydrolysis is the other important mechanism by which some lipids (glycerides and phosphoglycerides) degrade and can lead to a reduction in pH due to liberation of free fatty acids this was discussed in Chapter 10 (Part I Parenteral Application). This phenomenon is less important for oral formulations when compared to parenteral products, since the former generally have low amounts of water in the formulation. Hydrolysis could occur on storage if water is absorbed from or through the gelatin shell. 

In an own study we tested topical corticosteroids in combination with 5% lanolic acid.68 An improvement of barrier function could be detected. Formulations containing co-3 and co-6 fatty acids may help in the restoration of barrier properties. Higher efficacy of these products may be achieved by combining different classes of stratum corneum lipids 68 Escobar et al.64 showed a clinical improvement of scaling and plaque thickness for topical fish oil compared to the base-treated site in a four week treatment64... 

Gel-State PC. Hydrogenated soybean PC (HPC) contains only saturated fatty acids of which 85% is stearic acid. The transition temperature of HPC is 50-55°C, as compared to 50°C of the SC lipids. It is used in topical formulations as an excipient in drugs and in cosmetics. In contrast to the fluid-state PC, it forms lamellar structures in water, similar to the lamellar structures of the permeation barrier in SC. Two synthetic PCs, distearylphos-phatidylcholine and dipalmitoylphosphatidylcholine, with transition temperatures of 55°C and 38°C, respectively, are used as excipients for systemic drug formulations. 

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