CYCLIC HEXAPEPTIDES AS TACHYKININ ANTAGONISTS, THEIR PREPARATION AND PHARMACEUTICAL COMPOSITIONS THEREOF
Field of the invention
The invention refers to cyclic hexapeptide analogues of tachykinines of general formula (I)
(I)
where
R1 = H, linear or branched C1-4 alkyl
R3 = H, natural or not natural amino acid free or protected side chain
or
R3 = ((H2)n-R"
wherein
n = 1, 2, 3, 4, 5
R" = cyclooctyl, adamantyl, cyclohexyl, naphthyl
R" = phenyl when n is other than 1
R" = a substituted carboxyamide group when n = 1, 2
A1 Gln, DGln
A2 = Trp, DTrp
A3 = Phe, DPhe
W = CO-NR' , CH2-NR'
where
R' = H, CH3 and their pharmaceutically acceptable salts with acids
or organic or inorganic bases.
Tachykinins antagonist compounds of foraula (I) prove to be effective in the treatment of diseases where tachykinins play a pathogenic role, in particular in the treatment of arthritis , asthma, inflammations, tumor growth, gastrointestinal hypermotility, Huntington's disease, neuritis, neuralgia, migraine, hypertension, incontinence of urine, urticaria, carcinoid syndrome symptoms , influenza, and cold.
State of the Art
Tachykinins are a family of peptides characterized by the following common C-terminal sequence:
Phe-X-Gl y-Leu-Met-NH2
where X stands for an amino acid characterizing each of the tachykinins.
As far as mammals are concerned, the three tachykinins were called substance P (SP) (where X = Phe) , neurokinin A (NKA) (where X = Val) and neurokinin B (NKB) (where X = Val) and their neurotransmitter role, both at peripheral and central levels, was acknowledged (J.E. Maggio, Peptides. 1985. 6, 237-245 and P.C. Emson et al. , Neuropeptides and their peptidases, A.J. Turner and Ellis Horwood, England. 1987. PP. 87-106) .
The pharmacological and biochemical results conveyed by the literature show that the biological activity of tachykinins is mediated, in mammals' tissues, by three distinct receptors at least, called NK-1, NK-2, NK-3. Natural tachykinines exhibit a different
affinity with such three receptors. Highly potent tachykinins antagonists seem to be effective to reduce or antagonize pathological effects due to an excess of tachykinins in animals or man. The first generation tachykinins antagonists described, for instance, in US-A-4,481,139 - scarcely selective - were followed by the second generation ones (EP-A-401,177; EP-A-347,802; GB-A- 2,216,529), more selective.
Research in the field is anyway aimed at singling out higher affinity and activity antagonists, free from agonist activity on other receptors, hence suitable for therapeutical use.
Detailed Description of the Invention
This invention refers to cyclic hexapeptide analogues of tachykinins of general formula (I)
(I) R1 A
where
R1 = H, linear or branched C1-4 alkyl
R3 = natural or not natural amino acid free or protected side chain or
R3 = (CH2)n-R"
where
n = 1, 2, 3, 4, 5
R" = cyclooctyl, adamantyl, cyclohexyl, naphthyl
R" = phenyl when n is other than 1
R" = a substituted carboxyamide group when n = 1, 2
A1 = Gln, DGln
A2 = Trp, DTrp
A3 = Phe, DPhe
W = CO-NR' , CH2-NR'
where
R' = H, CH3 and their pharmaceutically acceptable salts with acids or organic or inorganic bases.
According to this invention, linear or branched C1-4 alkyl are selected in the group consisting of : methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl.
Natural amino acid is selected in the group consisting of : glycine, alanine, valine, leucine, isoleucine, proline, phenylalanine, tryptophan, methionine, serine. threonine, cysteine. tyrosine, asparagine, glutamine, aspartic acid, glutamic acid, lysine , arginine, histidine, in their L or D forms.
Not natural amino acid is selected in group consisting of β-alanine, D or L 2-aminoisobutyric acid, D or L 2,3-diaminopropionic acid, D or L norleucine, D or L alloisoleucine, D or L pyroglutamic acid, L or D 3-hydroxyproline, L or D 4-hydroxyproline, L or D phenylalanine substituted in the ortho, meta, or para position, L or D thienylalanine, L or D pyridylalanine, β(2- or 3- benzothienylalanine) , 1,2,3,4 tetrahydroisoquinoline-3-carboxyl acid.
Among the amino acid chain protectors , the following are given special consideration: Mbs, Mtr, NO2, Z, Tos, Pmc, For, Me, Ac. 2-
Br-Z, 2-Cl-Z, Bzl, 2,6-dichloro-Bzl, SO3H, Fmoc, OMe, OBzl, OFm, ONp, OSu.
Protected side chain of a natural or not natural amino acid means, in particular, L or D Arg (Mbs), L or D Arg(Mtr), L or D Arg(NO2), L or D Arg (Z), L or D Arg(Tos), L or D Arg(Pmc), L or D Trp(For), L or D Trp(Mts), L or D Tyr(Me), L or D Tyr(Ac), L or D Tyr(2-Br-Z), L or D Tyr(Bzl), L or D Tyr(2,6-dichloro-Bzl), L or D Tyr(SO3H), L or D Ser(Me), L or D Ser(Ac), L or D Ser(Bzl), L or D Ser(2,2-dichloro- Bzl), L or D Ser(SO3H), L or D Lys(Ac), L or D Lys(2-Br-Z), L or D Lys(2-Cl-Z), L or D Lys(Fmoc), L or D Lys(Z), L or D Lys(Tos), L or D Lys(Me), L or D Lys (Bzl), L or D Asp(OMe), L or D Asp(OBzl), L or D Asp(OFm), L or D Asp(ONp), L or D Asp(OSu), L or D Glu(OMe), L or D Glu(OBzl), L or D Glu(OFm), L or D Glu(ONp), L or D Glu(OSu).
Substituted carboxamide group means a CONR5R6 group, where R5 and R6 are equal or different and represent H or a linear or branched or cyclic alkyl, arylalkyl, aryl residue.
R5 and R6 together with the nitrogen atom can form a 5- or 6- terminal cycle including 4 or 5 carbon atoms or groups - CH2CH2NHCH2CH2-, CH2CH2N(CH3)CH2CH2 -, -CH2CH2OCH2C H2-.
In particular, NR5R6 can mean the residue of benzylamine, phenylethylamine even substituted with a halogen, 1- or 2- naphthylamine, cyclohexylamine, cyclooctylamine, adamantanamine, adamantyl-methylamine.
Among the compounds as per formula (I) of this invention, preference is given to
R1 = isobutyl
A2 = Trp
R3 = (CH2)nC6H11, where n = 2, 3, 4, 5; (CH2)n-(1-naphthyl) , where n
= 2, 3, 4, 5; (CH2)n-(1-adamantyl) , where n = 1, 2, 3, 4, 5; (CH2)n- cyclooctyl, where n = 1, 2, 3, 4, 5; (CH2)n-CP6H5, where n = 2, 3,
4, 5; (CH2)n-CONHBzl, where n = 1, 2; (CH2)n-CONMeBzl, where n = 1.
2; (CH2)n-CONHCH2C6H11, where n = 1, 2; (CH2)n-CONMeCH2C6H11, where n = 1, 2; (CH2)n-CONH-CH2(1-adamantyl) , where n = 1, 2; (CH2)n-
CONMe-CH2(1-adamantyl) , where n = 1, 2.
In particular the following compounds are preferred:
cyclo(Leu-Cha-Gln-Trp-Phe-βAla)
cydo(Leu-Asp(NHBzl)-Gln-Trρ-Phe-βAla)
cyclo(Leu-Asρ(NMeBzl)-Gln-Trp-Phe-βAla)
cyclo(Leu-Asp(NHCH2C6H11)-Gln-Trp-Phe-βAla)
cyclo(Leu-Asp(NHeCH2C6H11) -Gln-Trp-Phe-βAla)
cyclo(Leu-Glu(NHBzl)-Gln-Trρ-Phe-βAla)
cyclo(Leu-Glu(NHeBzl)-Gln-Trp-Phe-βAla)
cyclo(Leu-Glu(NHCH2C6H11)-Gln-Trp-Phe-βAla)
cyclo(Leu-Clu(NHeCH2C6H11)-Gln-Trp-Phe-βAla)
cyclo(Leu-Glu(NHCH2(1-adamantyl))-Gln-Trp-Phe-βAla)
cyclo(Leu-Glu(NMeCH2(1-adamantyl))-Gln-Trp-Phe-βAla)
cyclo(Leu-Asp(NHCH2(1-adamantyl))-Gln-Trp-Phe-βAla)
cyclo(Leu-Asp(NMeCH2(1-adamantyl))-Gln-Trp-Phe-βAla)
cyclo(Leu ψ [CH2NH]Asp(NHBzl)-Gln-Trp-Phe-βAla)
cyclo(Leu Ψ [CH2NH]Asp(NMeBzl)-Gln-Trp-Phe-βAla)
cyclo(Leu Ψ [CH2NH]Asp(NHCH2C6H11)-Gln-Trp-Phe-βAla) cyclo(Leu Ψ [CH2NH]Asp(NMeCH2C6H11)-Gln-Trp-Phe-βAla) cyclo(Leu Ψ [CH2NH]Glu(NHBzl)-Gln-Trp-Phe-βAla)
cyclo(Leu Ψ [CH2NH]Glu(NMeBzl)-Gln-Trp-Phe-βAla)
cyclo(Leu Ψ [CH2NH] Glu(NHCH2C611)-Gln-Trp-Phe-βAla) cyclo(Leu Ψ [CH2NH]Glu(NMeCH2C6H11)-Gln-Trp-Phe-βAla) cyclo(Leu Ψ [CH2NH]Glu(NHCH2(1-adamantyl) )-Gln-Trp -Phe-βAla) cyclo(Leu Ψ [CH2NH]Glu(NHCH2(1-adamantyl) )-Gln-Trp -Phe-βAla) cyclo(Leu Ψ [CH2NH]Asp(NHCH2(1-adamantyl) )-Gln-Trp -Phe-βAla) cyclo(Leu Ψ [CH2NH]Asp(NMeCH2(1-adamantyl) )-Gln-Trp -Phe-βAla) cyclo(Leu Ψ [CH2NMe]Asp(NHB zl)-Gln-Trp-Phe-βAla)
cyclo(Leu Ψ [CH2NMe]Asp(NMeBzl)-Gln-Trp-Phe-βAla)
cyclo(Leu Ψ [CH2NMe]Asp( HNCH 2C6H11)-Gln-Trp-Phe-βAla) cyclo(Leu Ψ [CH2NMe]Asp(NMeCH2C6H11)-Gln-Trp-Phe-βAla) cyclo(Leu Ψ [CH2NMe]Glu(NHBzl )-Gln-Trp-Phe-βAla)
cyclo(Leu Ψ [CH2NMe]Glu(NMeBzl)-Gln-Trρ-Phe-βAla)
cyclo(Leu Ψ [CH2NMe] Glu(NHCH 2C6H11)-Gln-Trp-Phe-βAla) cyclo(Leu Ψ [CH2NMe]Glu(NMeCH2C6H11)-Gln-Trp-Phe-βAla) cyclo(Leu Ψ [CH2NMe]Glu(NHCH2(1-adamantil) )-Gln-Trρ-Phe-βAla) cyclo(Leu Ψ [CH2NMe]Glu(NMeCH2(1-adamantil) )-Gln-Trρ-Phe-βAla) cyclo(Leu Ψ [CH2NMe]Glu(NHCH2(1-adamantil) )-Gln-Trρ-Phe-βAla) cyclo(Leu Ψ [CH2NMe]Glu(NMeC H2(1-adamantil) )-Gln-Trρ-Phe-βAla) cyclo(Leu Ψ [CH2NH]Asp(OBzl)-Gln-Trρ-Phe-βAla)
cyclo(Leu Ψ [CH2NMe] Asp(OBzl)-Gln-Trρ-Phe-βAla)
cyclo(Leu Ψ [CH2NMe] Nal-Gln-Trp-Phe-βAla)
cyclo(Leu Ψ [CH2NMe]Cha-Gln-Trp-Phe-βAla)
cyclo(Leu Ψ [CH2NMe]Cha-Gln-Trp-Phe-βAla)
cyclo(Leu Ψ [CH2NH ]Nal-Gln-Trp-Phe-βAla)
cyclo (Leu Ψ [CH2NMe]CH( (CH2)3Bzl)CO-Gln-Trp-Phe -βAla)
cyclo(Leu Ψ [CH2NH ]CH( (CH2)3Bzl)CO-Gln-Trp-Phe -βAla)
cyclo(Leu-NH-CH((CH2)3Bzl)CO-Gln-Trp-Phe-βAla)
The cyclic peptide analogues covered by the present invention can be prepared by known synthetic techniques in the solid phase or in solution. For the obtainment of linear peptides with the C-terminal carboxyl group in the form of free acid, solid supports such as resin phenylacetamidomethyl (PAM) or the resin p- hydroxymethylphenoxymethyl (Hang), can be used. In the case of PAM resin, the amine function of amino acids is protected by the t- butyloxycabonyl group which can be selectively deprotected by trifluoracetic acid, whilst final deprotection - with simultaneous peptide detachment from the polymer support - is secured by anhydrous hydrofluoric acid. In the case of the Hang resin, the amino acid amine function is protected by the 9-fluorenylmethoxycarbonyl group (Fmoc), selectively deprotected by piperidine, whilst final deprotonation - with simultaneous peptide detachment from the polymer support - is secured by trifluoracetic acid.
In both cases, the trifunctional amino acid side chains can be protected by the known methods described by literature. For the construction of the peptide chain on the insoluble polymer support, each amino acid is made to react in the form of free acid, in the
presence of a suitable coupling agent , e . g. dicyclohexyl carbodiimide (DCC) , used with additives , if any, such as hydroxybenzothiazole (HOBT) or benzothiazolyl-N- oxytridlmethylaminophosphonium hexafluorophosphate (BOP) ; as an alternative, the amino acid can be made to react in the form of symmetric anhydride, activated ester, or according to any of the other methods described in literature. Amino acid coupling reaction completion can be ninhydrin tested, as described by E.T. Kaiser et al. , Anal.Biochem. , 1970, 34 , 595.
Amino acids with the R3=(CH2)n-CONR5R6 group as side chain can be synthesized, e.g. starting from the corresponding acid (where the α- amino and α-carboxyl groups have been pre-protected) , by condensation with the suitable HNR5R6 amine and the use of activators such as those currently employed in peptide chemistry (BOP, PyBOP, HOBT) .
Amino acids whose side chain is represented by the (CH2)n-R" group can be synthesized by known organic chemistry techniques, such as, e.g., those described by Evans et al., J. Am. Chem. Soc., 112 (1990) 4011-4030; G.C. Barret, Chemistry and Biochemistry of the Amino Acids, Ed. G.C. Barret, Chapman & Hall, London, 1985, 246-296.
As for the -CH2-NR'- bond, it is synthesized according to the procedure described by Sasaki and Coy, Peptides, 1987, 8, 119. Such a procedure was extended to the synthesis in the solid phase according to the Fmoc strategy, as described by Przewosny et al., Peptides, 1990, 370. Specifically (see scheme shown hereunder): N-
methoxymethylamide as per formula 2 is prepared from the corresponding N-protected amino acid. The said amino acid is dissolved in methylene chloride; the solution is added with an equimolar amount of hydroxybenzotriazole and stirred for 20 minutes. Then, N-O-dimethylhydroxylamine.HCl dissolved in dichloromethane and added with an equimolar amount of a sterically hindered tertiary amine, e.g. diisopropylethylamine, is added to the said solution. The resulting mixture is kept under stirring for about 16 hours, after which it is washed with dilute aqueous HCl, with an NaHCO3 saturated solution, as well as with an NaCl saturated solution. The desired product can be purified, e.g. by chromatography on silica gel.
N-methoxymethylamide as per formula 3 is reduced to produce the corresponding aldehyde as per formula 4. e.g. with equimolar lithium aluminium hydride at 0ºC in an ether solution. On reaction completion, the mixture is treated with a solution of acid potassium sdphate in water.
The product is then isolated by extraction, with
ether, of the aqueous phase: for this purpose the ether phase is washed with dilute aqueous HCl, with NaCO3 saturated solution, and with an NaCl saturated solution.
B = Boc, Fmoc R2 = H; Me
The aldehyde as per formula 4 is allowed to react with the compound as per formula 6, or with the N-terminal end of a pentapeptide chain bound to the resin by a β-alanine residue. The initial Schiff base is reduced in situ, e.g. by sodium cyanoborohydride, to give a modified hexapeptide bound to the resin as per formula 7. After deprotection and detachment, performed as described above, the suitably freeze-dried raw peptide is purified to homogeneity, e.g. by high pressure reversed-phase preparative chromatography.
Cyclic peptide synthesis can be obtained via cyclization in solution after preparation - according to one of the aforementioned methods, in the solution or solid phase - of the linear precursor of the desired cyclic peptide. Cyclization is performed with condensing
agents and, if necessary, by activating the C-terminal carboxyl group of the cyclic precursor.
EXAMPLE
Preparation of the cyclic peptide :
cyclo(LeuΨ [CH2NH]Asp(NHBzl)-Cln-Trp-Phe-βAla) (ii)
a) Synthesis of the linear peptide having the following sequence: H-LeuΨ [CH2NH]Asp(NHBzl)-Gln-Trp-Phe-βAla-OH (i)
Synthesis of Boc-Asp(NHBzl)-OH: 323 g Boc-Asp-OBzl (Novabiochem, Switzerland) is solubilized in 70 mL dioxane; then the solution is added with 530 mg BOP, 37μL DIEA and, finally. 107 mg benzylamine. After 3 hours, the reaction mixture is dried and the residue is purified by chromatography on Mterck silica gel 60 (mesh 70-230) with ethyl acetate-1/n-hexane-1 (v/v), as eluent, Rf = 0.3.310 mg yield. Carboxyl group deprotection is obtained by dissolving 300 mg benzyl ester in 40 mL aqueous 952 ethyl alcohol and adding the solution to a suspension of 100 mg Pd/C (10% Pd) in 6 mL 95% aqueous ethyl alcohol. The environment is saturated with hydrogen and the reacting mixture is kept under hydrogen environment for 2 hours. Then, the solution is filtered and dried.
3.0 g Boc-βAla-PAM resin (Bachem, Switzerland), equal to 0.45 mmoles of amine groups, is fed to a Labortec SP 640 semi-automatic peptide synthesis reactor. The resin is washed as described in Table 1, cydes 6-7.
For resin coupling to the subsequent amino acid, symmetric anhydride is prepared by dissolution of 0.48 g Boc-Phe-OH in 5 mL
dichloromethane. The solution temperature is brought to 0ºC and added with 0.9 mL of a 1M solution of dicyclohexylcarbodiimide in dichloromethane. After 15 minutes, dlcyclohexylurea is filtered and the resulting solution is added to the deprotected resin. The resin is kept under stirring at ambient temperature for 60 minutes (cycle 8). The procedure is completed by washing (cycles 9-12) and the reaction is ninhydrin-tested by the Kaiser method. In case of a negative response, the Boc group is hydrolyzed with 50% TFA (cycles 1-4), before the subsequent amino acid coupling, which takes place according to the described procedure. The following residues are made to react in the same order, in the quantities indicated in brackets: Boc-Trp-OH (0.548 g), Boc-Gln-OH (0.443 g). Boc- Asp(NHBzl)-OH (0.581 g). After deprotection, Boc-Leu-H (0.242 g) dissolved in a dimethylformamide solution containing 5 mL 1% acetic acid is added to the resin; 5 mL of an NaBH3CN solution (70 mg) in a dimethylformamide solution containing 5 mL 1% acetic acid is allowed to drip under stirring for 40 minutes. The resin is kept under stirring at ambient temperature for about 6 hours. The procedure ends with washing (cycles 9-12) after which the ninhydrin test as by the Kaiser method is performed. In case of a negative response, the Boc group is hydrolyzed with 50% TFA. Then, the resin is washed (cycles 9-12) and dried under vacuum, with the obtainment of 1.25 g dry product. For peptide detachment from the resin, the product is placed in a Teflon reactor with 1.5 mL anisole and 0.75 mL dimethyl sulphide. The mixture temperature is brought to -50ºC and 15 mL
hydrofluoric acid is distilled therein; then the mixture is kept under stirring for 60 min. in an ice bath. Hydrofluoric acid is removed by nitrogen blowing. The raw product is dried under suction for about 2 hours, is washed with ethyl ether (15 mL twice), extracted in 50% acetic acid (15 mL three times) and filtered in a fritted disc filter funnel to remove the exhaust resin. The resdting solution is diluted with water and freeze-dried to yield 0.210 g raw product. Findly, the peptide is purified by reversedphase liquid chromatography and characterized by analytical HPLC, Waters C18 Deltapack 3-9 x 150 mm column with an acetonitrlle gradient containing 0.1% (v/v) trifluoracetic acid (phase B) vs. 0.1% (v/v) aqueous trifluoracetic acid (phase A), as well as 20 to 80% phase B, in 20 minutes, at a rate of 1 mL/min., with 210 nm UV monitoring. Retention time (Rt) = 9-2'; chromatographic purity: > 99%.
b) Cyclization of the above said peptide (1) into the cyclic peptide cyclo(Leu [CH2NH]Asp(NHBzl) -Gln-Trp-Phe-βAla (ii)
65 mg product (i) is dissolved in 35 mL DMF. The solution is added with 47 mg PyBOP, then 32 μL DIEA. The resulting solution is kept under stirring at ambient temperature for 2 hours , then DMF is removed under vacuum and the resul ting mixture freeze-dried. The cyclic peptide (ii) is purified by reversed-phase liquid chromatography and characterized by andyticd HPLC, Waters C18 Deltapack 3.9 × 150 mm column with an acetonitrile gradient containing 0.1% (v/v) trifluoracetic acid (phase B) vs. 0.1% (v/v)
aqueous trifluoracetic acid (phase A), as well as 20 to 80% phase B, in 20 min., at a rate of 1 mL/min., with 210 nm UV monitoring.
Retention time (Rt) = 10.6': chromatographic purity: >99%.
By the procedure described above and using suitable reagents, the following peptides are obtained:
H-Leu Ψ [CH2NH]Asp(NH-CH2-(1-adamantyl))-Gln-Trp-Phe-βAla-OH retention time (Rt) = 9.5'; chromatographic purity: > 99%.
H-LeuΨ[CH2NH]Asp(NH-CH2-C6H11)-Gln-Trp-Phe-βAla-OH
retention time (Rt) = 9.0'; chromatographic purity: > 99%.
H-Leu Ψ [ CH2NH ]Glu(NHBzl)-Gln-Trp-Phe-βAla-OH retention time (Rt) = 9.3'; chromatographic purity: > 99%.
H-LeuΨ[CH2NH]Glu(NMBzl)-Glu-Trp-Phe-βAla- OH
retention time (Rt) = 9.8'; chromatographic purity: > 99%.
H-LeuΨ[CH2NH]CH((CH2)3Bzl) -CO-Gln-Trp-Phe -βAla-OH
retention time (Rt) = 11 '; chromatographic purity: > 99%.
H-Leu-Asp(NHBzl) -Gln-Trp-Phe -βAla-OH
retention time (Rt) = 9.6'; chromatographic purity: > 99%'
H-Leu- Cha-Gln- Trp-Phe-βAla- OH
retention time (Rt) = 9.8'; chromatographic purity: > 99%.
H-LeuΨ[CH2NH]Asp(OBzl)-Gln-Trp-Phe-βAla- OH
retention time (Rt) = 10.7';chromatographic purity: > 99%
H-LeuΨ[CH2NH]Leu-Gln-Trp -DPhe-βAla- OH
retention time (Rt) = 7.7'; chromatographic purity: > 99%
H-LeuΨ[CH2NH]Lys(Z)-Gln-Trp-Phe- βAla- OH
retention time (Rt) = 8.9'; chromatographic purity: > 99%
H-Leu Ψ [CH2NH]Cha-Gln-Trp-Dphe-βAla-OH
retention time (Rt) = 9.0 ; chromatographic purity: > 99%
H-Leu Ψ [CH2NH]Nal-Gln-Trp-Phe-βAla-OH
retention time (Rt) = 9.9' ; chromatographic purity: > 99%
H-Leu Ψ [ CH2NMe]Cha-Gln-Trp-Phe-βAla-OH
retention time (Rt) = 11.1' ; chromatographic purity: > 99%
Which are cyclized into the following cyclic peptides : cyclo(Leu
[CH2NH]Asp(NH 2-(1-adamantyl) )-Gln-Trp-Phe-βAla)
retention time (Rt) = 11.0' ; chromatographic purity: > 99%.
cyclo(Leu Ψ [CH2NH]ASp(NH-CH2-C6H11)-Trp-Phe-βAla)
retention time (Rt) = 11.2'; chromatographic purity: > 99%.
cyclo(Leu Ψ [CH2NH]Glu(NHBzl)-Gln-Trp-Phe-βAla)
retention time (Rt) = 10.0'; chromatographic purity: > 99%.
cyclo(LeuΨ [CH2NH]Asp(NMeBzl)-Gln-Trp-Phe-βAla)
retention time (Rt) = 12.5'; chromatographic purity: > 99%.
cyclo(Le uΨ [CH2NH]CH((CH2)3Bzl)-CO-Gln-Trp-Phe-βAla)
retention time (Rt) = 13.5'; chromatographic purity: > 99%.
cyclo(Leu-Asp(NHBzl)-Gln-Trp-Phe-βAla)
retention time (Rt) = 10.6'; chromatographic purity: > 99%.
cyclo(Leu-Cha-Gln-Trp-Phe-βAla)
retention time (Rt) = 11.2' ; chromatographic purity: > 99%.
cycl o(Le u Ψ [CH2NH]Asp(OBzl)-Gln-Trp-Phe-βAla
retention time (Rt) = 9.8' ; chromatographic purity: > 99%
cyclo(Leu Ψ [CH2NH]Leu-Gln-Trp-DPhe-βAla)
retention time (Rt) = 9.4' ; chromatographic purity: > 99%
cycl o(Le u Ψ [CH2NH]Lys(Z)-Gln-Trp-Phe-βAla)
retention time (Rt) = 10.7' ; chromatographic purity: > 99%cycl o (Leu Ψ [ CH2NH] Cha-Trp-Phe- βAla)
retention time = (Rt) = 11.1'; chroaatograpdc purity: > 99 %cycl o(LeuΨ [CH2NH]Nal-Gln-Trp-Phe-βAla)
retention time (Rt) = 13.0'; chromatographic purity: > 99%
cyclo (leuΨ [CH2NMe]Cha-Gln-Trp-Phe-βAla)
retention time (Rt) = 12.2'; chromatographic purity: > 99%
BIOLOGICAL ACTIVITY
The ability of the peptides described in the present invention to interact with the neurokinine A receptor as agodsts or antagodsts was assessed through an in vitro test. The preparation used for the test was characterized by the fact that the biological response produced by tachykinins and related peptides was exclusively determined by the neurokinine A receptor (receptor NK-2). The sdd preparation consisted of isolated rabbit pulmonary artery affected by a dose dependent contraction brought about by tachykinins (Rovero et d., Neuropeptides, 1989, 13, 263-270). The determination of peptide activity in the test preparation was based on the use of an NKA concentration (3 nm) causing a response equd to 45% of max. response. The peptides considered herein were added to the preparation in growing concentrations. Their activity was assessed as inhibition of response to NKA. The capacity of the peptides described herein to interact with the P substance receptor (receptor NK-1) as agonists or antagonists was assessed through an in vitro
test, where the biological response produced by tachykinins and related peptides was exclusively determined at the SP receptor. The test preparation consisted of isolated guinea pig ileum affected by a dose-dependent contraction (Lee et al. , Schnied. Arch. Pharmacol. , 1982, 318, 281-287) . The determination of peptide activity in the test preparation was based on the use of an SP methyl ester concentration (10 nm) causing a response equal to 45% of max. response (S. Dion et al. , Life Sc ., 1987 , 41 , 2269-2278) . The peptides considered herein were added to the preparation in growing concentrations. Their activity was assessed as inhibition of response to SP with satisfactory results .
The compounds covered by the invention are suitable for therapeutical administration to higher animals and nan by the parenteral. oral, dermic, nasal , inhalatory and sublingual ways, with pharmaceutical effects matching the described properties. In case of parenteral administration (intravenous, intramuscular, intradermal ) , sterile solutions or freeze-dried preparations of the compounds are to be used. In case of oral administration, preparations such as tablets, capsul es and syrups are convedently used. Suitably dosed ointments and creams are utilizable by the dermic way. In case of nasal instillation, inhalation, and sublingual administration , the compounds to be used are respectively aqueous solutions, aerosol preparations, or capsul es.
Doses for therapeutical treatment range from 0.1 to 10 mg/kg body weight .