Drugs terpenes

Terpenes are polymers of the 5-carbon compound isoprene (Figure 1.12) and, as such, generally display properties similar to those of hydrocarbons. Terpenoids are substituted terpenes (i.e. contain additional chemical groups, such as an alcohol, phenols, aldehydes, ketones, etc.). Only a few such substances could be regarded as true drugs. Terpenes, such as limonene, menthol and camphor, form components of various essential oils with pseudo-pharmaceutical uses. A number of these molecules, however, exhibit anti-tumour activity, of which taxol is by far the most important. 

Drug Terpene/Vehicle Membrane Enhancement Ratio (ER) Reference... 

In the design of TDDS, the skin permeability often needs to be enhanced by various approaches including the use of skin permeation enhancers to reduce the barrier property of the skin. In the absence of permeation enhancers, systemic delivery of most drugs through the skin is limited, primarily because of the barrier function of the stratum corneum. Certain enhancers including some terpenes have a tendency to form eutectics when mixed with certain chemical entities. Terpenes are a group of chiral skin penetration enhancers that are derived from plant essential oils and are widely used as pharmaceutical excipients with various drugs. Terpenes are... 

Drug LogR of drug Terpene Log P of terpene Class and type of terpene Ref. 

Drugs, alkaloids, mycotoxins, amino acids, flavinoids, heterocyclic compounds, lipids, steroids, organic acids, terpenes, vitamins. Proteins, peptides, surfactants. 

L-699,392, Merck s drug for the treatment of chronic asthma, is an example of asymmetric amplification on an industrial scale (see Figure 13.19). The ketone reduction can be carried out stoichiometrically with a borane-(-)-a-pinene reagent. The terpene natural products are often mixtures of isomers and enantiomers. A reagent prepared from 98% optically pure (-)-a-pinene gives a product e.e. of 97%, but a reagent prepared from less expensive 70% optically pure (-)-a-pinene yields a product e.e. of 95%, which can be pushed to >99.5% by using an excess [30]. 

Ion mobility spectrometry (IMS [43]). Solid phase microextraction (SPME) using a 100 pm polydimethylsiloxane (PDMS) SPME fibre was used for head-space sampling and preconcentration of volatile markers of cocaine, MDMA and marijuana (methyl benzoate, piperonal and terpenes, respectively) in cargo containers. Analysis was then performed by IMS after thermal desorption of the drug markers from the fibre into the IMS analyser. 

The bulk of plant-derived medicines can be categorized into a number of chemical families, including alkaloids, flavonoids, terpenes and terpenoids, steroids (e.g. cardiac glycosides), as well as coumarins, quinines, salicylates and xanthines. A list of some better-known plant-derived drugs is presented in Table 1.16. 

FIGURE 12-13 Interaction of Gs with adenylyl cyclase. (PDB ID 1AZS) The soluble catalytic core of the adenylyl cyclase (AC, blue), severed from its membrane anchor, was cocrystallized with G,, (green) to give this crystal structure. The plant terpene forskolin (yellow) is a drug that strongly stimulates the enzyme, and GTP (red) bound to Gsa triggers interaction of Gsa with adenylyl cyclase. 

Williams, A.C., and B.W. Barry. 1991. The enhancement index concept applied to terpene penetration enhancers for human skin and model lipophilic (oestradiol) and hydrophilic (5-fluorouracil) drugs. Int JPharm 74 157. 

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. 

Cyclic monoterpenes increase the penetration of hydrophilic and lipophilic drugs [125-129]. Cornwell et al. found remarkable penetration enhancement of 5-fluorouracil after pretreatment with the noncyclic terpenes nerolidol, famesol,... 

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