Effect of terpenes

Trees and shrubs contain a group of fragrant compounds called terpenes. The simplest terpene is isoprene. All other terpenes are built around carbon skeletons constructed from one or more isoprene units. Plants emit terpenes into the atmosphere, as anyone who has walked in a pine or eucalyptus forest will have noticed. The possible effect of terpenes on the concentration of ozone in the troposphere has been the subject of much debate and has led to careful measurements of rates of reaction with ozone. 

Jain, A.K., N.S. Thomas, and R. Panchagnula. 2002. Transdermal drug delivery of imipramine hydrochloride. I. Effect of terpenes. J Control Release 79 93. 

El-Kattan, A.F., C.S. Asbill, and B.B. Michniak. 2000. The effect of terpene enhancer lipophilicity on the percutaneous permeation of hydrocortisone formulated in HPMC gel systems. Int J Pharm 198 179. 

Yamane, M. A., Williams, A. C. and Barry, B. W. Effects of terpenes and oleic acid as skin penetration enhancers towards 5-fluorouracil as assessed with time permeation, partitioning and differential scanning calorimetry. International Journal of Pharmaceutics 776 237-251, 1995. 

Ray S, Ghosal SK. Release and skin permeation studies of naproxen from hydrophilic gels and effect of terpenes as enhancers on its skin permeation. Boll Chim Farm 2003 142(3) 125-129. 

El-Kattan, A.F. Asbill, C.S. Kim, N. Michniak, B.B. The effects of terpene enhancers on the percutaneous permeation of drugs with different lipophili-cities. Int. J. Pharm. 2001, 215, 229-240. 

Further work has been undertaken to investigate the effect of terpenes as penetration enhancers and DSC studies have provided information on their thermotropic behaviour. Three endothermic transitions were found in the SC, at 62, 79 and 95 C. Pre-treatment with terpineol decreased the first transition, attributed to bilayer disruption, while all the terpenes decreased the second transition, which can be explained in terms of fluidization or extraction of lipids [16]. 

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