Patent Application: US-939004-A

Abstract:
the present invention provides methods for treating and preventing gynecomastia by administering 4 - hydroxy tamoxifen to a patient . when percutaneously administered to a patient &# 39 ; s breasts , 4 - hydroxy tamoxifen concentrates locally , and exerts an anti - estrogenic effect . in patients with gynecomastia , this reduces the effective estrogen - androgen ratio in the breast tissue , thereby reducing ductal proliferation , epithelial and stromal hyperplasia , and pain . in patients at risk for developing gynecomastia , 4 - hydroxy tamoxifen &# 39 ; s anti - estrogenic effect prevents tissue proliferation and its accompanying pain .

Description:
an important aspect of the present invention is the surprising discovery that 4 - hydroxy tamoxifen , when administered percutaneously , may be effective not only in treating but also in preventing gynecomastia . moreover , percutaneously administered 4 - hydroxy tamoxifen results in lower plasma levels of the drug than the standard dose of oral tamoxifen , which translates to fewer adverse side effects . accordingly , percutaneous 4 - hydroxy tamoxifen is an alternative to tamoxifen for both treatment and prophylaxis in this context . the compound 4 - hydroxy tamoxifen , or 1 -[ 4 -( 2 - n - dimethylaminoethoxy ) phenyl ]- 1 -( 4 - hydroxyphenyl )- 2 - phenylbut - 1 - ene , constitutes an active metabolite of the well characterized anti - estrogen compound , tamoxifen . due to the presence of a double bond between two carbon atoms , 4 - hydroxy tamoxifen exists in two stereoisomeric forms . according to the medical and biochemical literature , isomeric forms of 4 - hydroxy tamoxifen are commonly designated as cis and trans isomers . from a purely chemical perspective , however , this designation is not strictly accurate because each double bonded carbon atom does not contain an identical chemical group . therefore , it is more appropriate to refer to the isomers as e ( the so - called cis form ) and z ( the so - called trans form ) configurations . both the e and z isomers of 4 - hydroxy tamoxifen , either alone or in combination , are useful according to the present invention . the z isomer is preferred , however , because it is more active than the e isomer . 4 - hydroxy tamoxifen acts as a selective estrogen receptor modulator ( serm ) that exhibits tissue - specificity for estrogen receptive tissues . in breast tissue , it functions as an estrogen antagonist . studies have shown that 4 - hydroxy tamoxifen can regulate the transcriptional activity of estrogen - related receptors , which may contribute to its tissue - specific activity . in vitro , 4 - hydroxy tamoxifen exhibits more potency than tamoxifen , as measured by binding affinity to estrogen receptors , or ers , and a binding affinity similar to estradiol for estrogen receptors ( robertson et al ., 1982 ; kuiper et al ., 1997 ). z - 4 - hydroxy tamoxifen inhibits the growth in culture of normal human epithelial breast cells 100 fold more than z - tamoxifen ( malet et al ., 1988 ). although 4 - hydroxy tamoxifen is a tamoxifen metabolite , its usefulness for gynecomastia is not presaged by previous experience with tamoxifen itself . there is a noticeable dearth of published reports testing the efficacy of treatment with 4 - hydroxy tamoxifen . in addition , tamoxifen is extensively metabolized in humans , as shown in fig1 . thus , its action in vivo is the net result of individual actions by the parent compound and its metabolite compounds competing for the occupation of receptors within target tissues . for example , see jordan , 1982 . each of these compounds manifests different and unpredictable biological activities in different cells , determined in part by each compound &# 39 ; s individual effect on estrogen receptor conformation . that is , estrogen receptor binding of each compound generates a unique receptor - ligand conformation that recruits different cofactors , and results in varying pharmacologies for the different compounds ( wijayaratne et al ., 1999 ; giambiagi et al ., 1988 ). several examples of these varying effects have been documented . for instance , tamoxifen but not 4 - hydroxy tamoxifen is a potent rat liver carcinogen . ( carthew et al ., 2001 ; sauvez et al ., 1999 ). additionally , tamoxifen but not 4 - hydroxy tamoxifen reportedly initiates apoptosis in p53 (−) normal human mammary epithelial cells ( dietze et al ., 2001 ). by contrast , 4 - hydroxy tamoxifen exhibits a significant inhibitory effect on estrone sulphatase activity in mammary cancer cell lines , while tamoxifen has little or no effect in this regard ( chetrite et al ., 1993 ). methods for preparing 4 - hydroxy tamoxifen are well known . for example , u . s . pat . no . 4 , 919 , 937 describes a synthesis , derived from robertson and katzenellenbogen , 1982 , that occurs in stages : stage 1 — reaction between 4 -( β - dimethylaminoethoxy )- α - ethyldeoxybenzoin and p -( 2 - tetrahydropyranyloxy ) phenylmagnesium bromide ; stage 2 — separately from stage 1 , formation of 1 -( 4 - hydroxyphenyl )- 2 - phenyl - 1 - butanone by hydroxylation of 1 , 2 - diphenyl - 1 - butanone ; stage 3 — reaction between the products of stages 1 and 2 to form 1 -( 4 - dimethylaminoethoxyphenyl )- 1 -[ p - 2 - tetrahydropyranyloxy ) phenyl ]- 2 - phenylbutan - 1 - ol ; stage 4 — dehydration with methanol / hydrochloric acid produces 1 -[ p -( β - dimethylaminoethoxy ) phenyl ]- z - 1 -( p - hydroxyphenyl )- 2 - pheny - 1 - but - 1 - ene = 4 - oh - tamoxifen , a mixture of e and z isomers ; stage 5 — separation of the e and z isomers by chromatography and crystallization to constant specific activity . according to the present invention , 4 - hydroxy tamoxifen may be administered to a patient diagnosed with gynecomastia . the condition preferably will be in its florid phase , as it is believed that 4 - hydroxy tamoxifen primarily acts by decreasing the effective estrogen - androgen ratio at the breast tissue level . for example in pubescent males with active and painful gynecomastia , the condition may be treated by topical administration of 4 - hydroxy tamoxifen to one or both breasts . thus , one advantage of topical administration is the option of localized treatment of a single breast if the individual is experiencing only unilateral tissue proliferation . the present invention also contemplates administration of 4 - hydroxy tamoxifen prophylactically , to a patient at increased risk for developing gynecomastia . many risk factors for gynecomastia are well established . for instance , individuals with prostate cancer who undergo surgical castration or are medically rendered hypogonadal through the use of hormone therapy have an increased incidence of gynecomastia . prophylactic application of low - dose radiation therapy has been used to prevent gynecomastia from occurring in these patients ( gagnon et al ., 1979 ). a skilled medical practitioner can evaluate the pertinent risk factors to determine whether a patient will benefit from prophylactic use of 4 - hydroxy tamoxifen . pursuant to the present invention , 4 - hydroxy tamoxifen may be administered in any dosage form and via any system that delivers the active compound to breast estrogen receptors in vivo . preferably , the 4 - hydroxy tamoxifen is delivered by “ percutaneous administration ,” a phrase that denotes any mode of delivering a drug from the surface of a patient &# 39 ; s skin , through the stratum corneum , epidermis , and dermis layers , and into the microcirculation . this is typically accomplished by diffusion down a concentration gradient . the diffusion may occur via intracellular penetration ( through the cells ), intercellular penetration ( between the cells ), transappendageal penetration ( through the hair follicles , sweat , and sebaceous glands ), or any combination of these . percutaneous administration of 4 - hydroxy tamoxifen offers several advantages . first , it avoids the hepatic metabolism that occurs subsequent to oral administration ( mauvais - jarvis et al ., 1986 ). second , percutaneous administration significantly reduces systemic drug exposure , and the attendant risks from non - specifically activating estrogen receptors throughout the body ; this , because topical 4 - hydroxy tamoxifen is absorbed primarily into local tissues . in particular , when 4 - hydroxy tamoxifen is percutaneously applied to breasts , high concentrations accumulate in the breast tissue , presumably due to many estrogen receptors therein , without creating a high plasma concentration ( mauvais - jarvis et al ., supra ). pursuant to the present invention , therefore , 4 - hydroxy tamoxifen may be applied to any skin surface , but preferably to one or both breasts . although the invention is not constrained to any particular theory , clinically significant side effects of anti - estrogen agents occur when the agents displace estradiol in non - target tissues . because 4 - hydroxy tamoxifen and estradiol have similar binding affinities for estrogen receptors , a competition between them for receptor binding would be approximately equal when the concentration of each compound approximates that of the other . if the 4 - hydroxy tamoxifen concentration exceeds the estradiol concentration , the former will be bound preferentially to the estrogen receptors , and vice versa . accordingly , doses of 4 - hydroxy tamoxifen that result in plasma concentrations less than about 20 pg / ml , or the mean estradiol concentration in normal men , are preferred . the daily doses to be administered can initially be estimated based upon the absorption coefficients of 4 - hydroxy tamoxifen , the breast tissue concentration that is desired , and the plasma concentration that should not be exceeded . of course , the initial dose may be optimized in each patient , depending on individual responses . as noted above , by targeting 4 - hydroxy tamoxifen to breast tissue , high concentrations can be achieved in that tissue without simultaneously raising 4 - hydroxy tamoxifen plasma levels to a point where significant systemic competition for estradiol receptors occurs . as an example , in women , at a percutaneous dose of 1 mg / breast / day , 4 - hydroxy tamoxifen concentration in breast tissue exceeds normal estradiol concentrations in breast tissue by a factor of 4 . ( barrat et al ., 1990 ; pujol et al ., supra ). moreover , 4 - hydroxy tamoxifen applied in this manner reaches concentrations in breast tissue that are an order of magnitude higher than concentrations in plasma , i . e ., 10 : 1 . by contrast , the breast tissue to plasma ratio of 4 - hydroxy tamoxifen following oral administration of tamoxifen is about 5 : 1 . in men , breast tissue contains large numbers of er - positive cells , regardless of age . in fact , men have a higher percentage of er - positive breast cells than age - matched women without breast disease . breast tissue from gynecomastia also has a high level of er expression ( sasano et al ., 1996 ), and a significantly higher level of ki67 expression , a marker of proliferation ( shoker et al ., 2000 ). accordingly , male breast tissue , like female breast tissue , can capture 4 - hydroxy tamoxifen that has been released through skin . in a percutaneous formulation , doses on the order of 0 . 25 - 2 . 0 mg / breast / day of 4 - hydroxy tamoxifen should achieve the desired result , with doses of about 0 . 5 - 1 . 0 mg / breast / day being preferred . in particular embodiments , the dosage is about 0 . 25 , 0 . 5 , 0 . 75 , 1 . 0 , 1 . 25 , 1 . 5 , 1 . 75 or 2 . 0 mg / breast / day of 4 - hydroxy tamoxifen . percutaneous administration can be accomplished mainly in two different ways : ( i ) by mixing a therapeutically active compound or its non - toxic pharmaceutically acceptable salt with suitable pharmaceutical carriers and , optionally , penetration enhancers to form ointments , emulsions , lotions , solutions , creams , gels or the like , where an amount of said preparation is applied onto a certain area of the skin , or ( ii ) by incorporating the therapeutically active substance into patches or transdermal delivery systems according to known technology . the effectiveness of percutaneous drug administration depends on many factors , including drug concentration , surface area of application , time and duration of application , skin hydration , physicochemical properties of the drug , and partitioning of the drug between the formulation and the skin . drug formulations intended for percutaneous use take advantage of these factors to achieve optimal delivery . such formulations often comprise penetration enhancers that improve percutaneous absorption by reducing the resistance of the stratum corneum by reversibly altering its physiochemical properties , changing hydration in the stratum corneum , acting as co - solvent , or changing the organization of lipids and proteins in the intercellular spaces . such enhancers of percutaneous absorption include surfactants , dmso , alcohol , acetone , propyleneglycol , polyethylene glycol , fatty acids or fatty alcohols and their derivatives , hydroxyacids , pyrrolidones , urea , essential oils , and mixtures thereof . in addition to chemical enhancers , physical methods can increase percutaneous absorption . for example , occlusive bandages induce hydration of the skin . other physical methods include iontophoresis and sonophoresis , which use electrical fields and high - frequency ultrasound , respectively , to enhance absorption of drugs that are poorly absorbed due to their size and ionic characteristics . the many factors and methods relating to percutaneous drug delivery are reviewed in r emington : t he s cience and p ractice of p harmacy , alfonso r . gennaro ( lippincott williams & amp ; wilkins , 2000 ), at pages 836 - 58 , and in p ercutaneous a bsorption : d rugs c osmetics m echanisms m ethodology , bronaugh and maibach ( marcel dekker , 1999 ). as these publications evidence , those in the pharmaceutical field can manipulate the various factors and methods to achieve efficacious percutaneous delivery . 4 - hydroxy tamoxifen is a large and very lipophilic molecule ; hence , without assistance from penetration enhancers it poorly penetrates the skin . accordingly , formulations of 4 - hydroxy tamoxifen used in the present invention preferably comprise one or more penetration enhancers . alcohols are preferred enhancers because 4 - hydroxy tamoxifen is soluble in alcohol . isopropyl myristate also is a preferred enhancer . for percutaneous administration , 4 - hydroxy tamoxifen may be delivered in an ointment , cream , gel , emulsion ( lotion ), powder , oil or similar formulation . to this end , the formulation may comprise customary excipient additives , including vegetable oils such as almond oil , olive oil , peach kernel oil , groundnut oil , castor oil and the like , animal oils , dmso , fat and fat - like substances , lanolin lipoids , phosphatides , hydrocarbons such as paraffins , petroleum jelly , waxes , detergent emulsifying agents , lecithin , alcohols , carotin , polyols or polyglycols such as glycerol ( or glycerine ), glycerol ethers , glycols , glycol ethers , polyethylene glycol , polypropylene glycol , non - volatile fatty alcohols , acids , esters , volatile alcoholic compounds , urea , talc , cellulose derivatives , coloring agents , antioxidants and preservatives . according to the present invention , 4 - hydroxy tamoxifen also may be delivered via a transdermal patch . in one embodiment , the patch comprises a reservoir for the 4 - hydroxy tamoxifen formula . the patch may comprise ( a ) a solution - impermeable backing foil , ( b ) a layer - like element having a cavity , ( c ) a microporous or semi - permeable membrane , ( d ) a self - adhesive layer , and ( e ) optionally , a removable backing film . the layer - like element having a cavity may be formed by the backing foil and the membrane . alternatively , the patch may comprise ( a ) a solution - impermeable backing foil , ( b ) an open - pored foam , a closed - pore foam , a tissue - like layer or a fibrous web - like layer as reservoir , ( c ) if the layer according to ( b ) is not self - adhesive , a self - adhesive layer , and ( d ) optionally a removable backing film . in preferred embodiments of the invention , 4 - hydroxy tamoxifen is formulated in a hydroalcoholic gel . the amount of 4 - hydroxy tamoxifen in such a gel may range from about 0 . 001 to about 2 . 0 grams of 4 - hydroxy tamoxifen per 100 grams of gel . the amount of 4 - hydroxy tamoxifen also may range from about 0 . 01 to about 2 . 0 , about 0 . 01 to about 1 . 75 , about 0 . 01 to about 1 . 5 , about 0 . 01 to about 1 . 25 , about 0 . 01 to about 1 , about 0 . 01 to about 0 . 75 , about 0 . 02 to about 0 . 5 , about 0 . 03 to about 0 . 4 , about 0 . 04 to about 0 . 3 , about 0 . 05 to about 0 . 25 , about 0 . 05 to about 0 . 2 , about 0 . 05 to about 0 . 15 , or about 0 . 05 to about 0 . 1 gram of 4 - hydroxy tamoxifen per 100 grams of gel . preferably , it ranges from about 0 . 01 to about 0 . 1 gram of 4 - hydroxy tamoxifen per 100 grams of gel . thus , the amount of 4 - hydroxy tamoxifen per 100 grams of gel may be about 0 . 01 , 0 . 02 , 0 . 03 , 0 . 04 , 0 . 05 , 0 . 06 , 0 . 07 , 0 . 08 , 0 . 09 , 0 . 1 , 0 . 11 , 0 . 12 , 0 . 13 , 0 . 14 , 0 . 15 , 0 . 16 , 0 . 17 , 0 . 18 , 0 . 19 , 0 . 2 , 0 . 21 , 0 . 22 , 0 . 23 , 0 . 24 , 0 . 25 , 0 . 26 , 0 . 27 , 0 . 28 , 0 . 29 , 0 . 3 , 0 . 31 , 0 . 32 , 0 . 33 , 0 . 34 , 0 . 35 , 0 . 4 , 0 . 45 , 0 . 5 , 0 . 55 , 0 . 6 , 0 . 65 , 0 . 7 , 0 . 75 , 0 . 8 , 0 . 85 , 0 . 9 , 0 . 95 , 1 . 0 , 1 . 1 , 1 . 2 , 1 . 3 , 1 . 4 , 1 . 5 , 1 . 6 , 1 . 7 , 1 . 8 , 1 . 9 or 2 . 0 grams . it is also preferred that 4 - hydroxy tamoxifen formulations comprise one or more fatty acid esters as a penetration enhancer . one highly preferred example of a fatty acid ester penetration enhancer is isopropyl myristate . when isopropyl myristate is used in a gel , the amount may range from about 0 . 1 to about 5 . 0 grams per 100 grams of gel . the amount of isopropyl myristate also may range from about 0 . 1 to about 4 . 5 , about 0 . 2 to about 4 . 0 , about 0 . 3 to about 3 . 5 , about 0 . 4 to about 3 , about 0 . 4 to about 2 . 5 , about 0 . 5 to about 2 . 0 , about 0 . 5 to about 1 . 9 , about 0 . 5 to about 1 . 8 , about 0 . 5 to about 1 . 7 , about 0 . 5 to about 1 . 6 , about 0 . 5 to about 1 . 5 , about 0 . 6 to about 1 . 4 , about 0 . 7 to about 1 . 3 , about 0 . 8 to about 1 . 2 , about 0 . 9 to about 1 . 1 , or about 1 . 0 gram per 100 grams of gel . preferably , the amount of isopropy myristate ranges from about 0 . 5 to about 2 . 0 grams per 100 grams of gel , and most preferably it ranges from about 0 . 9 to about 1 . 1 grams per 100 grams of gel . 4 - hydroxy tamoxifen formulations of the invention generally will comprise one or more nonaqueous vehicles . these vehicles should be capable of dissolving both 4 - hydroxy tamoxifen and any penetration enhancer used . they also should have a low boiling point , preferably less than 100 ° c . at atmospheric pressure , to permit rapid evaporation upon contact with the skin . examples of suitable non - aqueous vehicles include ethanol , isopropanol and ethyl acetate . ethanol and isopropanol are preferred . in particular , ethanol effectively contributes to the percutaneous absorption of 4 - hydroxy tamoxifen by rapidly evaporating upon contact with skin . the amount of nonaqueous vehicle in a gel formulation can range between 40 % and 85 %, and generally ranges between 54 % and 85 % by weight . preferably the amount of nonaqueous vehicle in a gel formulation ranges between 60 % and 80 %, and more preferably between 65 % and 75 % by weight . formulations also may comprise an aqueous vehicle , which permits solubilization of any hydrophilic molecules in a formulation , and also promotes diffusion of lipophilic molecules from the formulation to the skin . an aqueous vehicle also can regulate ph . aqueous vehicles include alkalinizing and basic buffer solutions , including phosphate buffered solutions ( e . g ., dibasic or monobasic sodium phosphate ), citrate buffered solutions ( e . g ., sodium citrate or potassium citrate ) and simply purified water . the amount of an aqueous vehicle preferably ranges between 15 % and 45 % by weight of a gel formulation , and more preferably between 25 % and 35 %. additionally , 4 - hydroxy tamoxifen formulations may comprise one or more gelling agents to increase the viscosity of a formulation and / or to function as a solubilizing agent . depending on the gelling agent &# 39 ; s nature , it may constitute between 0 . 1 % and 20 % by weight of a formulation , preferably between 0 . 5 % and 10 %, more preferably between 0 . 5 % and 5 % and still more preferably between 1 % and 5 %. preferred gelling agents include carbomers , cellulose derivatives , poloxamers and poloxamines . more particularly , preferred gelling agents are chitosan , dextran , pectins , natural gum and cellulose derivatives such as ethyl cellulose , hydroxypropyl cellulose , hydroxyethyl cellulose , hydroxypropyl methyl cellulose ( hpmc ), carboxymethyl cellulose ( cmc ), and the like . one highly preferred gelling agent is hydroxypropyl cellulose . when a formulation comprises a gelling agent , in particular a non - preneutralized acrylic polymer , it may advantageously also comprise a neutralizing agent . the neutralizing agent / gelling agent ratio preferably is between 10 : 1 and 0 . 1 : 1 , more preferably between 7 : 1 and 0 . 5 : 1 , and still more preferably between 4 : 1 and 1 : 1 . a neutralizing agent should form , in the presence of the polymer , salts that are soluble in the vehicle . a neutralizing agent also should permit optimum swelling of polymer chains during neutralization of charges and formation of polymer salts . useful neutralizing agents include sodium hydroxide , ammonium hydroxide , potassium hydroxide , arginine , aminomethylpropanol , trolamine and tromethamine . those skilled in the art will select a neutralizing agent according to the type of gelling agent employed in a formulation . when cellulose derivatives are used as gelling agents , however , no neutralizing agents are required . table 1 describes the composition of two highly preferred 4 - hydroxy tamoxifen gel formulations . four patients with breast cancer received [ 3 h ]- 4 - hydroxy tamoxifen in an alcoholic solution applied directly to the breasts at specified intervals between 12 hours to 7 days prior to surgery to excise diseased tissue . after surgery , both the excised tissue and the normal breast tissue surrounding the tumor contained radioactivity ( kuttenn et al ., 1985 ). in a follow - up study , 9 of 12 patients scheduled for surgical excision of hormone - dependent breast cancer received z -[ 3 h ]- 4 - hydroxy tamoxifen ( 80 μci ) in a 60 % alcoholic solution , and 3 patients received z [ 3 h ]- tamoxifen ( 80 μci ) for comparison . the patients received [ 3 h ]- labeled drug applied directly on the affected breasts at specified intervals ranging from 12 hours to 7 days before surgery to excise diseased tissue . breast tissue from three regions : the tumor , tissue immediately surrounding the tumor , and normal tissue , was excised and immediately frozen in liquid nitrogen . additionally , plasma and urine samples were obtained at scheduled intervals and frozen until analysis . table 2 shows results from the analyses performed . 4 - hydroxy tamoxifen concentrated predominantly in the cytosolic and nuclear fractions of breast tissue , where estrogen receptors are present . in these intracellular sites , 4 - hydroxy tamoxifen remained unmetabolized except for limited isomerization from the z to the e form . retention in the breast lasted approximately 4 days in the 4 - hydroxy tamoxifen group , but was shorter and far weaker in the tamoxifen group . the percentage of radioactivity identified as [ 3 h ]- 4 - hydroxy tamoxifen in breast tissue after percutaneous administration decreased slowly over seven days ( from 97 % to 65 %). during this period a progressive isomerization of the z isomer into the e isomer occurred , with similar percentages observed at day 7 ( 32 % and 33 %). the radioactivity in blood due to [ 3 h ]- 4 - hydroxy tamoxifen increased gradually , with a plateau from days 4 to 6 . this contrasts with [ 3 h ]- tamoxifen , which rapidly appeared in the blood , plateauing at 2 days . at 36 hours following percutaneous [ 3 h ]- 4 - hydroxy tamoxifen administration , only 0 . 5 % of the radioactivity administered showed in the blood . in contrast to the near absence of 4 - hydroxy tamoxifen metabolism in the breast tissue , marked metabolism occurred in blood . in blood , at 24 hours after administration , 68 % of radioactivity represented 4 - hydroxy tamoxifen , 18 % represented n - desmethyl - 4 - hydroxy tamoxifen , and 11 % represented bisphenol . peak urinary elimination occurred at a later time following percutaneous administration of 4 - hydroxy tamoxifen compared to percutaneous tamoxifen . following application of 4 - hydroxy tamoxifen , a progressive increase of metabolites , mostly n - desmethyl - 4 - hydroxy tamoxifen and bisphenol , was observed in the urine . this example demonstrates that percutaneous application of 4 - hydroxy tamoxifen to the breasts results in a substantial and lasting local tissue concentration of the drug , with minimal metabolism , stable and very low plasma concentrations , and slow elimination via the urine . these attributes of percutaneously applied 4 - hydroxy tamoxifen are anticipated to be particularly important for the prevention and treatment of gynecomastia . demonstration of the pharmacokinetics and pharmacodynamics of percutaneously administered 4 - oh - tamoxifen compared to 20 mg of oral tamoxifen this study compared the tissue and plasma concentrations of 4 - hydroxy tamoxifen after percutaneous administration via a hydroalcoholic gel with tissue and plasma concentrations of 4 - hydroxy tamoxifen after oral administration of tamoxifen ( pujol , 1995 ). thirty - one patients scheduled for breast cancer surgery were randomly assigned to 1 of 5 groups . they received treatment with either oral tamoxifen or percutaneous 4 - hydroxy tamoxifen as outlined in table 3 . treatment was daily and lasted for 3 - 4 weeks prior to surgery . the study evaluated three different doses of 4 - hydroxy tamoxifen ( 0 . 5 , 1 , or 2 mg / day ) and two areas of application ( either to both breasts or to a large surface of skin including arms , forearms , and shoulders ). one group of patients received 20 mg / day ( 10 mg b . i . d .) of oral tamoxifen ( nolvaldex ®). during surgery , two samples ( 1 cm 3 each ) of breast tissue were excised , one tumoral and the other macroscopically normal . they were immediately frozen in liquid nitrogen until assayed . blood samples were obtained on the day of and the day prior to surgery . all tissue and plasma samples were analyzed for 4 - hydroxy tamoxifen concentration by gas chromatograph / mass spectrometry ( gc - ms ). pre and post - treatment blood samples were assayed for complete blood counts ( cbc ), bilirubin , serum glutamic - pyruvic transaminase ( sgpt ), serum glutamic - oxaloacetic transaminase ( sgot ), alkaline phosphatase , creatinine , estradiol , follicle - stimulating hormone ( fsh ), lutenizing hormone ( lh ), sex hormone - binding globulin ( shbg ), cholesterol , high - density lipoprotein ( hdl ), low - density lipoprotein ( ldl ), triglycerides , fibrinogen , and anti - thrombin iii . table 4 below summarizes the concentration of 4 - hydroxy tamoxifen found in breast tissue and plasma . normal and tumor breast tissues contained similar concentrations of 4 - hydroxy tamoxifen in all five treatment groups . 4 - hydroxy tamoxifen concentrated at higher amounts in breast tissue when the gel was applied directly to the breasts , rather than to other large skin surfaces . side effects did not pose a significant problem . cutaneous treatment did not cause any local irritation . one woman in group 2 ( 0 . 5 mg / day of 4 - hydroxy tamoxifen gel ) reported dizzy spells , cystitis , and mild vaginitis occurring on the seventh day of treatment . one woman in group 1 ( oral tamoxifen ) reported hot flashes and mild vaginitis on the fifth day of treatment . no differences existed between the pre - and post treatment blood samples for any of the hematology or serum chemistry evaluations in the patients who received 4 - hydroxy tamoxifen gel . however , a statistically significant decrease in anti - thrombin iii and fibrinogen and a statistically significant increase in platelet and lymphocyte counts were observed in the oral tamoxifen group , consistent with the biologic effects of this drug observed in other studies . thus , percutaneously applied 4 - hydroxy tamoxifen is an especially attractive method of preventing and treating gynecomastia due to its reduced adverse effects . demonstration of tolerance and pharmacokinetics of percutaneously administered 4 - oh - tamoxifen in healthy women this study demonstrates the tolerance and pharmacokinetics of topically applied 4 - hydroxy tamoxifen gel in healthy premenopausal women , aged 18 - 45 . each participant applied the gel daily for the duration of two menstrual cycles . three doses and two gel concentrations were tested , as summarized in table 5 . for groups a - c , the gel , containing 20 mg of 4 - hydroxy tamoxifen / 100 g , was dispensed from a pressurized dose - metering pump that delivered 0 . 25 mg of 4 - hydroxy tamoxifen / dose . the study of group c was suspended because the quantity of gel was too large to be applied to a single breast . groups d and e received a more concentrated gel that contained almost 3 times as much 4 - hydroxy tamoxifen : 57 mg of 4 - hydroxy tamoxifen / 100 g , or 50 mg of 4 - hydroxy tamoxifen / 100 ml of gel . this more concentrated gel also was delivered by a dose - metering pump that supplied 0 . 25 mg of 4 - hydroxy tamoxifen / dose . on the first day of the following menstruation , treatment , which consisted of daily application of the gel over two menstrual cycles , began . blood samples were collected 24 hours following the morning application of gel on days 7 , 20 and 25 of the first and second cycles . on the last day of administration , day 25 of the second menstrual cycle , serial blood samples were collected prior to application and at 0 . 5 , 1 , 1 . 5 , 2 , 3 , 4 , 6 , 12 , 18 , 24 , 36 , 48 , and 72 hours after application of the gel . the samples were analyzed for 4 - hydroxy tamoxifen , estradiol , progesterone , fsh and lh . plasma concentrations of 4 - hydroxy tamoxifen remained detectable 72 hours after the last gel application . therefore , to ensure that data points were obtained until 4 - hydroxy tamoxifen became undetectable in the blood , additional blood samples were collected from some participants at intervals up to 92 days following the last application of gel . table 6 displays the mean ± standard deviation ( sd ) plasma concentrations of 4 - hydroxy tamoxifen , with ranges in parentheses . a single 0 . 5 mg dose did not produce detectable plasma concentrations of 4 - hydroxy tamoxifen , but 6 of 12 patients had detectable plasma concentrations (& gt ; 5 pg / ml ) after a single dose of 1 mg . fig2 shows a plasma concentration - time curve , following the last administration on day 25 of the second menstrual cycle . table 7 shows mean pharmacokinetic parameters that relate to the last administration , on day 25 of the second menstrual cycle . auc 0 - 24 = area under the concentration - time curve for 0 - 24 hours ; c av = calculation of area under the curve over 24 hours ( auc 0 - 24 ) divided by 24 hours ; c max = maximal concentration in plasma ; t 1 / 2 = half - life ; t ( 1stc & lt ; loq )= first timepoint at which the plasma concentration was below the limit of quantification ; t max = time of maximal concentration in plasma . the data are consistent with a dose response across the three doses tested ( 0 . 5 , 1 , and 2 mg ). the more concentrated gel was better absorbed , by approximately double , than the less concentrated gel , based on auc and c av . biological tolerance was excellent in all 36 patients . the treatment did not affect fsh , lh , estradiol , or progesterone hormone levels during the menstrual cycles . moreover , echographic examination of the ovaries at the end of treatment was normal in all patients , showing normal sized developing follicles . one patient developed an allergic reaction to the gel , and 10 reported facial acne ( 5 of which had a past history of acne ). in summary , this study indicates that the exposure to 4 - hydroxy tamoxifen after topical application increases with dose , that plasma concentrations of 4 - hydroxy tamoxifen are lower than typical estradiol concentrations ( 80 pg / ml ), and that there is no detectable laboratory or clinical evidence of systemic effects . because of this , it is anticipated that the percutaneous application of 4 - hydroxy tamoxifen will be especially useful in for the prevention and treatment of gynecomastia . each of the following references , in its entirety , is incorporated herein by reference : barrat , j ., b . de ligniπres , l . marpeau , l . larue , s . fournier , k . nahoul , g . linares , h . giorgi , and g . contesso , effet in vivo de l &# 39 ; administration locale de progestπrone sur l &# 39 ; activitπ mitotique des galactophores humains , j . gynecol . obstet . biol . reprod . 19 : 269 - 274 ( 1990 ) ( french ). braunstein , g . d ., aromatase and gynecomastia , endocr . relat . cancer , 6 : 315 - 24 ( 1999 ). bronaugh and maibach , percutaneous absorption : drugs cosmetics mechanisms methodology , marcel dekker 1999 . carthew , p ., p . n . lee , r . e edwards , r . t . heydon , b . m . nolan , e . a . martin , cumulative exposure to tamoxifen : dna adducts and liver cancer in the rat , arch . toxicol ., 75 : 375 - 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