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`Santen/Asahi Glass Exhibit 2017
`Micro Labs v. Santen Pharm. and Asahi Glass
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`EP 0 364 417 A1
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`PROSTAGLANDIN DERIVATIVES FOR THE TREATMENT OF GLAUCOMA OR OCULAR HYPERTENSION
`
`The invention is concerned with the use of prostaglandin derivatives of PGA, P68, P60, PGE and PGF.
`in which the omega chain has been modified with the common feature of containing a ring structure, for the
`treatment of glaucoma or ocular hypertension. The invention relates also to ophthalmic compositions.
`containing an active amount of these prostaglandin derivatives, and the manufacture of such compositions.
`Glaucoma is an eye disorder characterized by increased intraocular pressure, excavation of the optic
`nerve head and gradual loss of the visual field. An abnormally high intraocular pressure is commonly known
`to be detrimental to the eye, and there are clear indications that. in glaucoma patients, this probably is the
`most important factor causing degenerative changes in the retina. The pathophysiological mechanism of
`open angle glaucoma is, however, still unknown. Unless treated successfully glaucoma will lead to blindness
`sooner or later, its course towards that stage is typically slow with progressive loss of the vision.
`The intraocular pressure, IOP (abbr. of intraocular pressure) can be defined as according to the formula:
`l0P=Pe+FxR (1)
`'
`'
`‘
`where Pe is the episcleral venous pressure, generally regarded as being around 9 mm Hg, F the flow of
`aqueous humor, and Ft the resistance to outflow of aqueous humor through the trabecular meshwork and
`adjacent tissue into Schlemm's canal.
`Besides passing through Schlemm's, canal aqueous humor might also pass through the ciliary muscle
`into the suprachoroidal space and finally leave the eye through sclera. This uveoscleral route has been
`described for instance by Bill (1975). The pressure gradient in this case is insignificant compared to the
`gradient over the interior wall of Schiemm's canal and adjacent tissue in the former case. The flow limiting
`step along the uveoscleral r0ute is assumed to be the flow from the anterior chamber into the supra-
`choroidal space.
`A more complete formula is given by:
`iOP = P. + (Fa-FMB
`(2)
`where Fe and R are defined as above, Ft is the total outflow of aqueous humor and Fu is the fraction
`passing via the uveoscleral route.
`lOP in human beings is normally in the range of 12 - 22 mm Hg. At higher values, for instance over 22
`mm Hg, there is a risk that the eye may be affected.
`In one particular form of glaucoma,
`low tension
`glaucoma, damage may occur at intraocular pressure levels otherwise regarded as physiologically normal. .
`The reason for this could be that
`the eye in these individuals is unusually sensitive to pressure. The
`opposite situation is also known. that some individuals may exhibit an abnormally high intraocular pressure
`without any manifest defects in the visual field or optic nerve head. Such conditions are usually referred to
`as ocular hypertension.
`Glaucoma treatments can be given by means of drugs, laser or surgery. In drug treatment, the purpose
`is to lower either the flow (F) or the resistance (R) which, according to formula (1) above, will result in a
`reduced IOP; alternatively to increase the flow via the uveoscleral route which according to formula (2) also
`gives a reduced pressure. Cholinergic agonists, for instance pilocarpine, reduce the intraocular pressure
`mainly by increasing the outflow through Schlemm's canal.
`Prostaglandins, which recently have met an increasing interest as lOP-lowering substances may be
`active in that they will cause an increase in the uveoscleral outflow (Crawford et al, 1987, and Nilsson et al,
`1987). They do not appear, however to have any effect on the formation of aqueous humor or on the
`conventional outflow through Schlemm’s canal (Crawford et al, 1987).
`instance in US 4599353 and EP
`' The use of prostaglandins and their derivatives is described for
`871037149, and by Bito LZ et al (1983), Camras CB et al (1981, 1987a, 1987b, 1988), Giuffre G (1985).
`Kaufman PL (1986), Kersetter JR et al (1988), Lee P-Y et al (1988) and Villumsen J et al (1989).
`With respect
`to the practical usefulness of some of the previously described prostaglandins and
`derivatives, as suitable drugs for treating glaucoma or ocular hypertension, a limiting factor is their property
`of causing superficial irritation and vasodilation in the conjunctiva. It is probable, moreover, that prostaglan-
`dins have an irritant effect on the sensory nerves of the cornea. Thus local side effects will arise in the eye
`already when the amounts of prostaglandin administered are quite small - that is, already when the doses
`are lower than those that would be desirable for achieving maximum pressure reduction. it has thus been
`found, for instance,
`that for this reason it
`is clinically impossible to use PGFga-1-isopropyl ester in the
`
`amount that w0u|d give maximum pressure reduction. Prostaglandins, being naturally occurring autacoids,
`are very potent pharmacologically and affect both sensory nerves and smooth muscle of the blood vessels.
`Since the effects caused by administrations of PGFga and its esters to the eye, comprise in addition to
`pressure reduction also irritation and hyperemia (increased blood flow), the doses currently practicable in
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`EP 0 364 417 A1
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`clinical tests are necessarily very low. The irritation experienced when PGFm or its esters are applied,
`consists mainly in a feeling of grittiness or of having a foreign body in one's eye,
`this being usually
`accompanied by increased lacrimation.
`We have now found that a solution to the problems discussed above is the use of certain derivatives of
`prostaglandins A, B, D. E and F, in which the omega chain has been modified with the common feature of
`containing a ring structure, for the treatment of glaucoma or ocular hypertension.
`The prostaglandin derivatives have the general structure
`
`alpha chain
`
`omega chain
`
`wherein A represents the alicyclic ring 08-012 and the bonds between the ring and the side chains
`represent the various isomers. ln PGA, PGB, PGD, PGE and PGF A has the formula
`
`0 \
`V
`
`Q
`
`0
`\‘
`
`
`
`K, I
`
`.--“
`
`PGA
`I
`
`PGB
`II
`
`o‘
`
`OH
`a
`
`II
`0
`
`PGD
`I II
`
`0
`t
`
`‘
`
`/
`
`\"‘\/
`E
`OH
`
`PGE
`Iv
`
`t“
`
`OH
`i
`
`I/
`
`‘I\
`s
`OH
`
`PGF
`v
`
`N
`
`’
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`The invention is based on the use of derivatives characterized by their omega chain and various
`modifications of the alpha chain is therefore possible still using the inventive concept. The alpha chain could
`typically be the naturally occuring alpha chain, which is esterified to the structure
`
`WCOO R1
`
`in which R1 an alkyl group, preferably with 1-10 carbon, especially 1-6 atoms, for instance metyl, ethyl,
`propyl, isopropyl, butyl, isobutyl, neopentyl or benzyi or a derivative giving the final substance equivalent
`properties as a glaucoma agent. The chain could preferably be a CG‘Cio chain which might be saturated or
`unsaturated having one or more double bonds, and allenes, or a triple bond and the chain might contain
`one or more substituents such as alkyl groups, alicyclic rings, or aromatic rings with or without hetero
`atoms.
`
`The omega chain is defined by the following formula:
`
`(13)
`
`(14)
`
`(15-24)
`
`C
`
`B
`
`C
`
`-
`
`D
`
`-
`
`R
`
`wherein
`
`C is a carbOn atom (the number is indicated within parenthesis)
`B is a single bond, a double bond or a triple bond
`D is a chain with 1-10, preferably 2-8, and especially 2-5.
`and particularly 3 carbon atoms, optionally interrupted by preferably not more than two hetero atoms (0,8,
`or N), the substituent on each carbon atom being H, alkyl groups, preferably lower alkyl groups within 1-5
`carbon atoms, a carbonyl group, or a hydroxyl group, whereby the substituent on C15 preferably being a
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`EP 0 364 417 A1
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`carbonyl group, or (R)-OH or (8)-OH; each chain D containing preferably not more than three hydroxyl
`groups or not more than three carbonyl groups,
`R2 is a ring structure such as a phenyl group which is unsubstituted or has at least one substituent selected
`from 01-05 alkyl groups, C1-C4 alkoxy groups, trifluoromethyl groups, Ci'CS aliphatic acylamino groups,
`nitro groups, halogen atoms, and phenyl group; or an aromatic heterocyclic group having 5-6 ring atoms,
`like thiazol, imidazole, pyrrolidine, thiophene and oxazole; or a cycloalkane or a cycloalkene with 3-7 carbon
`atoms in the ring, optionally substituted with lower alkyl groups with 1-5 carbon atoms.
`Some examples on derivatives which were evaluated are the following (for structure information see
`Table l):
`(1 ) 16-phenyl-17,18,19,20-tetranor-PGF2a~isopropylester
`(2) 17-phenyl-18,19,20-trinor—PGFad-isopropylester
`(3) 15-dehydro-17-phenyI-18,19,20-trinor-PGF2Q-isopropylester
`(4) 16-phenoxy-17,18,19,20-tetranor-PGFag-isopropylester
`(5) 17-phenyl-18,19,20-trinor-PGEz-lsopropylester
`(6) 13,14-dihydro-17-phenyl-18,19,20-trinor-PGAz-isopropylester
`(7) 15-(R)-17-phenyl-18,19,20-trinor-PGF2a-isopropylester
`(8) 16-[4-(methoxy)-phenyl]-17,18,19,20-tetranor-PGFga-isopropylester
`(9) 13,14-dihydro-17-phenyl-18,19,20-trinor-PGFad-isopropylester
`(10) 18-phenyl-19,20-dinor-PGFag-isopropylester
`(20) 19-phenyl-20-nor-PGFga-isopropylester
`The most preferred derivatives at present are those in which the omega chain of the prostaglandin has
`the 18,,1920-trinor form, and especially the 17-phenyl analogs such as the 15-(Fi)- 15-dehydro and 13,14-
`dihydro-17—phenyl'-,181920‘trmor forms. Such derivatives are represented by (3),
`(6),
`(7) and (9) in the
`formulas given in Table i.
`In the formula given above the most preferred structure at present is accordingly obtained when the
`prostaglandin is a derivative of PGA, PGD, PGE or PGF. especially of PGAz, PGDz. PGEg and PGFga
`B is a single bond or a double bond
`D is a carbon chain with 2-5, especially 3 atoms; 015 having a carbonyl or (8)-OH substituent and C16'C19
`having lower alkyl substituents, or preferably H
`H2 is a phenyl ring optionally having substituents selected among alkyl and alkoxy groups.
`The invention thus relates to the use of certain derivatives of PGA, PGB, PGD, PGE and PGF for the
`
`treatment of glaucoma or ocular hypertension. Among these derivatives defined above it has been found
`that some are irritating or otherwise not optimal, and in certain cases not even useful due to adverse effects
`and these are excluded in that
`the group of prostaglandin derivatives defined above is
`limited to
`therapeutically effective and physiologically acceptable derivatives. 80 is
`for
`instance (1) 16-phenyl-
`17,18,19,20-tetranor-PGFag-isopropyl ester irritating while this can be eliminated by substituting the phenyl
`ring with a methoxy group giving formula (8) which represents a therapeutically more useful compound,
`The method for treating glaucoma or ocular hypertension consists in contacting an effective intraocular
`pressure reducing amount of a composition, as aforesaid, with the eye in order to reduce the eye pessure
`and to maintain said pressure on a reduced level. The composition contains 01-30 1.19, especially 1-10 LLg,
`per application of the active substance i.e. a therapeutically active and physiologically acceptable derivative
`from the group defined above; the treatment may advantageously be carried out in that one drop of the
`composition, corresponding to about 30 ul. is administered about 1
`to 2 times per day to the patient's eye.
`This therapy is applicable both to human beings and to animals.
`The invention further relates to the use of
`therapeutically active and physiologically acceptable
`prostaglandin derivatives from the group defined above for the preparation of an ophthalmological composi-
`tion for the treatment of glaucoma or ocular hypertension.
`The prostaglandin derivative is mixed with an ophthalmologically compatible vehicle known p__er se. The
`vehicle which may be employed for preparing compositions of this invention comprises aqueous_solutions
`as e.g. physiological salines, oil solutions or ointments. The vehicle furthermore may contain ophthal-
`mologically compatible preservatives such as e.g. benzalkonium chloride, surfactants like e.g. polysorbate
`80,
`liposomes or polymers,
`for example methyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone and
`hyaluronic acid; these may be used for increasing the viscosity. Furthermore,
`it
`is also possible to use
`soluble or insoluble drug inserts when the drug is to be administered.
`The invention is also related to ophthalmological compositions for topical treatment of glaucoma or
`ocular hypertension which comprise an effective intra ocular pressure reducing amount of a prostaglandin
`derivative as defined above and an ophthalmologically compatible carrier, the effective amount comprising a
`dose of about 0.1-30 u. in about 10-50 v. of the composition.
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`EP 0 364 417 A1
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`in anamount, varying with
`in the experiments carried out in this investigation the active compound,
`potency of the drug. from 30 rag to 300 ug/ml was dissolved in a sterilized aqueous solution (saline 0.9 %)
`containing 0.5 % polysorbate-80 as solubilizing agent.
`The invention is illustrated by means of the following non-limitative examples.
`
`—_
`Synthesis of prostaglandin derivatives
`
`Example 1: Preparation if 16-phenyl-17,18,19.20-tetranor PGFga-isopropyl ester (l)_
`
`A 50 ml round bottom flask equipped with a magnetic stirring bar was charged with 17.5 mg (0.04
`mmol) 16-phenyI-17,18,19,20-tetranor PGFm (Cayman Chemical), 5 ml CH20I2,30.2 mg (0.23 mmol)
`diisopropylethylamine. This solution was stirred at -10 °C and 13.5 mg (0.07 mmol) of isopropyltriflate
`(freshly prepared) was added. This solution was allowed to stand at -10° C for 15 min and was then slowly
`warmed to room temperature. When the esteritication was complete according to TLC (usually after 3-4 h at
`room temperature) the solvent was removed in vacuo. The residue was diluted with 20 ml ethylacetate.
`washed with 2x10 ml 5 % sodium hydrogencarbonate and 2x10 ml 3 % citric acid. The organic layer was
`dried over unhydrous sodium sulfate. The solvent was removed in vacuo and the residue was purified by
`column chromatography on silica gel-60 using ethyl acetate: aceto? ms eluent. The title compound was
`obtained as a colourless oily substance (71 % yield).
`
`Nuclear Magnetic Resonance spectrum (CDCI3)- ppm: 5
`
`1.2 (6H d)
`2.85 (2H d)
`3.85 (1H m)
`4.15 (1H t)
`3.3 (1H q)
`5.0 (1H m)
`5.3-5.7 (4H m) 7.15-7.35 (5H m)
`
`
`Example 2: Preparation o_f 17-phenyI-18,19,20- trinor PGFga-isopropyl ester (2_)
`
`A 50 ml round bottom flask equipped with a magnetic stirring bar was charged whith 20 mg (0.05
`mmol) 17-phenyl—18,19,20-trinor PGFga (Cayman Chemicals), 6 mi acetone, 39.2 mg (0.25 mmol) DBU and
`42.5 mg (0.25 mmol) isopropyl iodide. The solution was allowed to stand at room temperature for 24 h, the
`solvent was removed in vacuo and the residue was diluted with 30 ml of ethyl acetate, washed twice with 10
`ml 5 % sodiumhydrogen'carbonate and 10 ml 3 % citric acid. The solvent was removed in vacuo, and the
`crude product was chromatographed on silica gel-60 using ethyl acetate: acetone 2:1 as_eiu§i-t.- The title
`compound (2) was obtained as an oily substance (65 % yield).
`
`Nuclear Magnetic Resonance spectrum (CDCla)- ppm: 5
`
`1.2 (6m)
`3.9 (1H m)
`4.1 (1H t)
`4.2 (1H m)
`4.9 (1H m)
`5.4-5.6 (4H m)
`7.1-7.3 (5H m)
`
`Example 3: Preparation g 15-dehydro-17-phenyI-18,19.20-trinor PGFm-isopropyl ester (3)
`
`20.9 mg (0.092 mmol) DDQ was added to a solution of 10 mg (0.023 mmol) 17-phenyl-18,19.20 trinor
`PGan-isopropyl ester (2) in 8 ml dioxane. The reaction mixture immediately turned brown, the reaction
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`EP 0 364 417 A1
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`mixture was stirred at room temperature for 24 h. The precipitate formed was filtered, washed with 10 ml
`ethyl acetate, the filtrate was diluted with 10. ml ethylacetate washed with 2x10 ml water, 2x10 ml NaOH IM
`and 20 ml brine. The organic layer was dried on unhydrous sodium sulfate and the solvent was removed in
`
`vacuo, the residue was purified by column chromatography on silica gel using ethyl acetate: ether 1:1 as
`eluent. The title compound (3) was obtained as a colourless oily substance (76 % yield).
`
`Nuclear Magnetic Resonance spectrum (CDCIg),- ppm: 5
`
`iszd)
`tonHm)
`AZUHm)
`50UHm)
`54QHm)
`aanm
`a7pHm
`7.15-7.35 (5H m)
`
`Example 4: Preparation o_f 16-phenoxy-17,18,19,20 -tetranor PGga-isopropyl ester(4).
`
`Following a procedure similar to that described in example 2 using 20 mg (0.051 mmol) 16-phenoxy-
`17,18,19,20 -tetranor PGFZQ (Cayman Chemicals). The title compound (4) was an oily substance (53.2 %
`yield).
`
`Nuclear Magnetic Resonance spectrum (CDCl3)- ppm: 5
`
`iszm
`aspHm)
`42UHm)
`450Hm)
`sonHm)
`54QHm)
`s7eHm)
`aepHm)
`Z3QHm)
`
`Example 5: Preparation 9‘ 17-phenyI-18,19.20-trinor PGE2«isopropyl ester (3)
`
`Following a procedure similar to that described in example 2 using 10 mg (0.026 mmol) 17-phenyl-
`18,19,20- trinor PGEz (Cayman Chemicals). The crude product was purified by column chromatography on
`silica gel-60 using ether as eluent. The title compound (5) was an oily substance (38.9 °/o yield).
`
`Nuclear Magnetic Resonance spectrum (CDCls)- ppm: 5
`
`12pHm
`se¢1QHm)
`AQUHm)
`53QHm)
`5GQHm)
`xszm)
`
`Example 6: Preparation-if 13,14-dihydro-17-phenyl-18,19,20-trinor PGAz-isopropyl ester @_
`
`Following a procedure similar to that described in example g using 10 mg (0.026 mmol) 13,14-dihydro-
`17-phenyl PGA2 (Cayman Chemicals). The crude product was chromatographed on silica gel-60 using ether
`as eluent.
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`EP 0 364 417 A1
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`Nuclear Magnetic Resonance spectrum (CDCla)- ppm: 5
`
`1.2 (6H d)
`4.35 (1H m)
`5.0 (1H rn)
`5.4 (2H m)
`7.3 (5H m)
`
`70
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`Example 7: Preparation of 15-(R)-17-phenyl-18,19,20-trinor PGFaa-isopropyl ester Q (Table II)
`-J
`
`:1 Preparation of 1-(S)-2-oxa-3-oxo-6-(Fi)-(3-oxo-5-phenyl-1-trans-pentenyl)-7-(R)—(4-phenylbenzoyloxy)-cis-
`
`bicyclo [3,3,0] octane (13).
`
`18 g (0.05 mol) alcohol (11), 32 g (0.15 mol) DCC, 39.1 g (0.5 mol) DMSO (newly distilled from CaHg)
`and 30 ml DME were charged to a 200 ml flask under nitrogen. Orthophosphoric acid was added in one
`portion, and an exothermic reaction occured. The reaction mixture was stirred mechanically at room
`temperature for 2h, and the resultant precipitate was filtered and washed with DME. The filtrate (12) can be
`used directly for Emmon condensation reaction.
`-
`To a suspension of 1.2 g (0.04 mol) NaH (80 % washed with n-pentane to remove mineral oil) in 100 ml
`DME under nitrogen was added dropwise 12.3 g (0.048) dimethyl-2-oxo-4—phenylbutyl-phos’phonate in 30 ml
`DME. The mixture was stirred mechanically for 1h at room temperature,
`then cooled to -10 °C and a
`solution of the crude aldehyde (12) was added in dropwise. After 15 min at 0 °C and 1h at room
`temperature the reaction mixture was neutralized with glacial acetic acid, the solvent was removed under
`vaccum, and to the residue was added 100 ml ethyl acetate, washed with 50 ml water and 50 ml brine. The
`
`organic layer was dried over unhydrous sodium sulfate. The solvent was removed in vacuo and the
`resulting white precipitate filtered and washed with cold ether. The title compound (13) v17as obtained as a
`crystalline substance mp 1345-1355 (53 % yield).
`
`7.2 Preparation of 1-(S)-2‘oxa-aoxo-6-(R)‘[3-(R,S)-hydroxy-4—phenyl-1~trans-pentenyl]-7-(F1)-(4-phenylben-
`
`zoyloxy) cis-bicyclo [3,3,0]octane (14).
`
`10 g (0.021 mol) enone (13) and 3.1 g (0.008 mol) cerouschloride heptahydrate in 50 ml methanol and
`20 ml CH2C|2 were charged to a 200 ml round bottom flask equipped with a magnetic stirring bar and was
`cooled to -78 'C under nitrogen. Sodium borohydride was added in small portions. after 30 min the
`reaction mixture was quenched by addition of saturuted NH4CI, and extracted with 2x50 ml ethyl acetate.
`The extracts were dried and concentrated to leave a colourless oil (98 °/o yield).
`
`1:: Preparation of 1-(S)-2-oxa-3-oxo-6-(R)-[3-(Fi,S)-hydroxy-4-phenyl-1-trans-pentenyI]-7-(Ft)-hydroxy-cis-
`
`bicyclo-[3,3,0] octane (15).
`
`To a solution of 9.8 g (0.02 mol) ketal (14) in 100 ml absolute methanol was added 1.7 (0.012 mol)
`potassium carbonate. The mixture was stirred with a magnetic bar, at room temperature after 3 h. The
`mixture was neutralized with 40 ml HCI
`1 M. and extracted with 2x50 ml ethyl acetate. The extracts were
`then dried on unhydrous sodium sulfate and concentrated. The crude product was chromatographed on
`silica gel using ethyl acetate: acetone as eluent. The title compound (15) was obtained as an oily substance
`(85 % yield).
`
`7.4 Preparation of 1-(S)-2-oxa-3-hydroxy-6-(R)-[3-(R,S)-hydroxy-4—phenyl-1-trans-penteny|]-7-(R)-hydroxy-
`fi-bm] (Ti)-
`
`To a solution of 39(0011 mol) lactone (15) in 60 ml unhydrous THF. stirred magnetically and cooled to
`-78 °C. 4.5 9 (0.0315 mol) DlBAL—H in toluene was added dropwise. After 2h the reaction mixture was
`
`quenched by addition of 75 ml methanol. The mixture was filtered,the filtrate was concentrated in vacuo and
`the residue was chromatographed on silica gel-60 using ethyl acetate: acetone 1:1 as elue_nt. The title
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`EP 0 364 417 A1
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`compound (16) was obtained as a semisolid substance (78 % yield).
`
`15 Preparation o_f 15-(R,S)-17-phenyl-18,19,20-trinor PGFgaU 7).
`
`2.5 g (25 mmol) sodium methyl suifinylmethide in DMSO freshly prepared from sodium anhydride and
`DMSO) was added dropwise to a solution of 5.6 g (12.6 mmol) 4-caboxybutyl
`triphenyl-phosphonium
`bromide in 12 ml DMSO. To the resultant red solution of the ylide was added dr0pwise a solution of the 1.2
`g (4.2 mmol) hemiacetal (16) in 13 ml DMSO, and the mixture was stirred for 1h. The reaction mixture was
`diluted with 10 9 ice and 10 ml water and extracted with 2x50 ml ethyl acetate, whereafter the aqueous
`layer was cooled, acidified with HCI 1 M and extracted with ethyl acetate, and then the organic layer was
`dried and concentrated. The resulting crude product was a colourless substance. The purity of the title
`compound (17) was estimated by TLC on silica gel using ethyl acetate: acetone: acetic acid 121:0.2 v/v/v as
`eluent.
`
`7_.6 Preparation of 15-(R)—17-phenyl-18,19,20- trinor PGFga-isopropyl ester (7_)
`
`The crude product (17) was esterified following a procedure similar to that described in example 2 the
`product was purified by column chromatography on silica gel-60 using ethyl acetate as eluent and the
`resulting mixture of C15 epimeric alcohol were separated.
`The title compound (7) was obtained as a colourless oily substance (46 ‘70 yield).
`
`Nuclear Magnetic Resonance spectrum (CDCIs),- ppm: 5
`
`1.2 (6H m)
`3.9 (1 H m)
`4.15 (2H m)
`4.95 (1H m)
`5.4 (2H m)
`5.6 (2H m)
`7.2 (5H m)
`
`Examples: Preparation o_f 16-[4-(methoxy)phenyl]-17,18,19,20-tetranor PGFga-isopropyl ester (_8_)_.
`
`Following a procedure similar to that described in example 7 with modified step 7-2. the aldehyde 1__2
`described in step 7-2 was reacted with dimethyl--2-oxo-3--[4-(methoxy)phenyl]-propylphosphonate and was
`purified by column chromatography on silica gel--60 using ethyl acetate: toluene 1: 1 as eluent A colourless
`oily substance was obtained (57 °/o yield)
`The title compound 16--[4-(methoxy)phenyl]--17, 18, 19, 20-tetranor PGan-isopropyl ester (8) was obtained
`as an oily substance, and purified by column chromatography on silica gel--60 using ethyl acetate as eluent
`(46 % yield).
`
`Nuclear Magnetic Resonance spectrum (CDCI3)- ppm: 5
`
`1.2 (6H d)
`2.3 (2H d)
`3.75 (3H 8)
`3.9 (1H m)
`4.15 (1H m)
`4.3 (1H m)
`5.0 (1H m)
`5.4 (2H m)
`5.6 (2H m)
`6.8 (2H d)
`7.2 (2H d)
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`Example 9: Preparation 9t 13.14-dihydro-17-phenyl-18,19,20-trinor PGFga-isopropyl ester @
`
`Following a procedure similar to that described in example 7, with minor modification. 5 g (0.018 mol)
`enone (13)
`in 100 ml THF was reduced using 2.03 g 10 %— pd/c under hydrogen atmosphere. After
`completion of the reaction (as determined by TLC on silica gel using ethylacetate: toluene 1:1 as eluent) the
`
`mixture was filtered on celite. The filtrate was concentrated in vacuo and an oily substance was obtained
`(%%ymm
`T
`The final product 13,14-dihydro-17—phenyl-18,19,20-trinor PGFga-isopropyl ester containing a mixture of
`C15 epimeric alcohols were separated by preparative liquid chromatography using 40 °/o CHacN in water
`v/v as eluent.
`
`Nuclear Magnetic Renonance spectrum (CDCI3)- ppm: 5
`
`1.2 (6H d)
`3.6 (1H m)
`3.9 (1H m)
`4.15 (1 H m)
`5.0 (1H m)
`5.4 (2H m)
`7.2 (5H m)
`
`Example 10: Preparation of 18-phenyl-19,20-trinor PGFga-isopropyl ester 92)
`
`Following a procedure similar to that described in example (7) with modified step 7-2. The aldehyde
`(12) described in 7-2 was reacted with dimethyl-2—oxo-5-phenyl pentyl phosphonate gave a crystalline
`substance trans-enone lactone (67 % yield).
`The final product 18-phenyl-19,20-dinor PGFga-isopropyl ester (10) was purified by column chromatog-
`raphy on silica gel-60 using ethyl acetate as eluent gave a colourless oil (41 °/o yield).
`1.2 (6H d)
`3.95 (1 H m)
`4.10 (1 H m)
`4.20 (1 H m)
`5.0 (1H m)
`5.4 (2H m)
`5.6 (2H q)
`7.2 (5H m)
`
`Example 11: Preparation if 19-phenyl-20-nor-PGFga-isopropyl ester L29)
`
`Following a procedure similar to that described in example (7) with modified step (7—2).
`The aldehyde (12) described in (7-2) was reacted with dimethyl-2-oxo-6-phenyl-hexylphosphonate gave
`a colourless oil trans-enone lactone (56 °/o yield).
`The final product 19-phenyl-20-nor-PGFad-isopropyl ester (20) was a colourless oil, and was purified by
`column chromatography on silica gel-60 using ethyl acetate as eluent (30 % yield).
`
`Nuclear Magnetic Resonance spectrum (CDCla)‘ppm: 6
`
`1.2 (6H d)
`2.6 (2H t)
`3.9 (1H m)
`4.1 (1H m)
`4.2 (1H m)
`5.0 (1H m)
`5.4 (2H m)
`5.5 (2H t)
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`7.2 (5H m)
`
`Studies o_f 33E pressure lowering flag fl adverse reactions
`
`The intraocular pressure (IOP) was determined in animals with a pneumatonometer (Digilab Modular
`OneTM, Bio Rad), specially calibrated for the eye of the particular species. The cornea was anaesthetized
`with 1:2 drops of oxibuprocain before each lOP measurement.
`In healthy human volunteers lOP was
`measured with applanation tonometry or with an air puff tonometer (Keeler pulsair). For applanation
`tonometry either a pneumatonometer (Digilab) or Goldmann's applanation tonometer mounted on a slit lamp
`microscope was used. The cornea was anaesthetized with oxibuprocain before each measurement with
`applanation tonometry. No local anaesthesia was employed before measurement with the pulsair tonometer.
`The ocular discomfort after application of the test substances was evaluated in cats. The behaviour of
`cats after topical application of the test drug was followed and ocular discomfort was graded on a scale
`from 0 to 3, 0 indicating complete absence of any signs of discomfort. and 3 indicating maximal irritation as
`obvious from complete lid closure.
`Conjunctival hyperemia after topical application of the test substances was evaluated in rabbits. The _
`conjunctiva at the insertion of the superior rectus muscle of the eye was inspected or photographed with
`regular intervals and the degree of hyperemia was later evaluated from the color photographs in a blind
`manner. Conjunctival hyperemia was evaluated on a scale from 0 to 4, 0 indicating complete absence of
`any hyperemia, and 4 indicating marked hyperemia with conjunctival chemosis.
`For determination of the effects on the intraocular pressure, primarily monkeys (cynomolgus) were
`employed. The reason for this is that the monkey eye is highly reminiscent of the human eye and therefor,
`generally, drug effects are readily extrapolated to the human eye. However, the disadvantage of using the
`monkey eye as a model is that the conjunctiva in this species is pigmented making it impossible to evaluate
`conjunctival hyperemia and furthermore, the monkey eye is relatively insensitive to irritation. Therefore. the
`cat eye, being very sensitive to prostaglandins was used for evaluating ocular discomfort and the rabbit eye
`with pronounced tendency to hyperemic reactions was used for evaluating conjunctival and episcleral
`hyperemia.
`it is evident from Table lll that modification of the omega chain of the prostaglandin skeleton introduced
`new and unexpected features to the prostaglandins with respect to ocular irritation (discomfort). Particularly
`17-phenyl,18,19,20-trinor-PGan-lE and analogs were unique in exhibiting a complete loss of ocular irritation
`with retained lOP lowering effect in monkeys. Whereas the 17-phenyl,18,19,20-trinor-PGF20, derivatives
`were extremely well
`tolerated, 16-phenyl-17,18,19,20-tetranor-PGFaa-lE caused clear ocular discomfort
`although to a lesser degree than PGan-lE or 15-propionate-PGE2-IE (Table III). However, substituting a
`hydrogen atom in the phenyl ring with a methoxy group having electron donating properties rendered the
`molecule practically free of ocular irritating effect, Table III. It is also evident from Table III that 18-phenyl-
`19,20.-dinor-PGFMIE, 19-phenyi-20-nor—PGF2a-IE as well as 17-phenyl-=18,19,20-trinor-PGE2-IE and 13,14-
`dihydro-17-phenyl-18,19,20-trinor-PGA2-lE, had no or very little irritating effect
`in the eye of cats. This
`indicates that the invention not only is valid for 16-, and 17-tetra- and trinor analogs of PGan but for a
`range of omega chain modified and ring substituted analogs of PGFga (as exemplified with 16-phenyl-
`17.18.19,20-tetranor-PGFga-1E to 19-phenyI-20-nor-PGFad-1E), and more importantly even for different
`members of the prostaglandin family such as PGE2 and PGAz modified in an analogous way (Table Ill).
`Thus. modifying the omega chain and substituting a carbon atom in the chain with a ring structure
`introduces completely new, unexpected and advantageous qualities to naturally occuring prostaglandins in
`that the irritating effect in the conjunctiva and cornea is abolished.
`In the case of 16‘phenyl-17,18,19.20-
`tetranor-PGFga-lE exhibiting some irritating effect substituting a hydrogen atom in the ring structure with
`e.g. a methoxy group attenuates or abolishes the irritating effect.
`in addition to the lack of ocular discomfort the omega chain modified analogs also exhibited an
`advantage over naturally occuring prostalgandins in that
`they caused considerably less conjunctival
`hyperemia as studied in the rabbit eye (Table lV). Particularly, 15-dehydro-17-phenyl-18,19,20-trinor-PGFZQ-
`lE,f3,14-dihydro-17-phenyl-18.19,20-trinor—-PGF2a-1E, and 13,14-dihydro-17-phenyl-18,19,20-trinor PGAz-IE
`were advantageous in this respect. Also 18-phenyI-19,20-dinor-PGFga-lE and 19-phenyl-20-nor-PGFaa-IE
`induced very little conjunctival hyperemia (TablelV).
`,
`The intraocular pressure lowering effect of omega chain modified and ring-substituted prostaglandin
`analogs is demonstrated in Table V.
`It can be seen that particularly 16-phenyl-tetranor and 17-phenyI-trinor
`prostaglandin analogs significantly reduced IOP in animal eyes (Table V).
`in all but
`two series of
`experiments cynomolgus monkeys were used.
`It is of particular interest to note that 17-phenyl~18,19,20-
`trinor PGan-derivatives exhibiting no ocular irritation and only modest conjunctival/episcleral hyperemia
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`It should furthermore be observed that both i6-phenyI-17,18,19,20-
`significantly lowered IOP in primates.
`tetranor-PGFa-IE, 18-phenyl-19,20-dinor-PGF2a -lE and 19-phenyl-20-nor-PGFa-IE reduced the intraocular
`pressure, thus, modification of the omega chain and substituting a carbon atom in the chain with a ring
`structure do not render the molecule inactive with respect to the effect on the intraocular pressure.
`Furthermore,
`it should be observed that substituting a hydrogen on the ring structure of 16-phe-
`nyl,17,18,19,20-tetranor-PGF2aelE with a methoxy group eliminated much of the ocular irritating effect
`preserving most of the intraocular pressure lowering effect. Thus, omega chain modified and ring substi-
`tuted prostagiandin analogs reduce IOP effectively in animals. it is further demonstrated in Table V that 16-
`phenoxy-t7,18,19,10-tetranor-PGF2a-IE effectively lowers the intraocular pressure as studied in cats. Thus,
`substituting carbon 17 in the omega chain with a hetero atom,
`in this case oxygen, does not render the
`molecule inactive with respect to the effect on IOP.
`It is noteworthy that most of the 17-phenyl,18,19,20-trinor-prostaglandin analogs had poor int