Hussain et al. 14 have recently evaluated a new aminopeptidase inhibitor, boroleucine, and its effect on the degradation rate of leucine enkephalin in the nasal cavity of rat using an in vitro perfusing method.

Since nasal biopharmaceutical research is currently directed on absorption and bioavailability, we shall describe in more detail the most recently introduced enhancer systems, namely micro- spheres, STDHF and glycyrrhetinic acid derivatives.

23 Pontiroli, A.E., Alberetto, M., Calderara, A., Pajetta, E. and Pozza, G. (1989) Nasal absorption of glucagon and human calcitonin to healthy subjects: a comparison of powders and spray solutions and of different enhancing agents, Eur.

27 Pontiroli, A.E., Alberetto, M., Pajetta, E., Calderara, A. and Gozza, E. (1987) Human insulin plus sodium glycocholate in a nasal spray formulation: improved bioavailability and effectiveness in normal subjects, Diabetes Metab.

28 Aungst, B.J., Rogers, N.J. and Shefter, E. (1988) Comparison of nasal, rectal, buccal, sublingual and intramuscular insulin efficacy and the effects of a bile salt absorption promotor, J. Pharmacol.

[0003] Ethanol constitutes a good solubilizing agent for perfuming ingredients, and additionally has the advantage of being inexpensive and of alloWing the formulation of trans parent compositions.

[0005] A ?rst route consists in replacing ethanol With aqueous compositions containing hydrophilic solubilizing agents such as polyethoxylated hydrogenated castor oils.

Moreover, the presence of Water in a large quantity is capable of causing degradation of the perfuming ingredients over time and therefore of adversely affecting the olfactory characteristics of the product.

[0006] Another solution further consisted in providing perfume compositions in Which the ethanol is at least partially replaced by one or more volatile silicones Which are lineariof the polydimethylsiloxane type4or cyclic.

[0007] HoWever, the applicant has noW discovered, sur prisingly, that by choosing a particular combination of silicone compounds not described in the prior art, it Was possible to obtain a perfume composition Whose rate of evaporation is close to that of ethanol and possessing a ?ash point greater than or equal to 00 C., preferably greater than or equal to 10° C. [0008] The subject of the present invention is therefore a perfume composition comprising a mixture of fragrant mate rials in a physiologically acceptable carrier comprising a mixture of polydimethylsiloxanes, characterized in that the said mixture of polydimethylsiloxanes consists of hexam ethyldisiloxane and octamethyltrisiloxane in a hexamethyl disiloxane to octamethyltrisiloxane Weight ratio ranging from 30:70 to 70:30.