TRANSDERMAL ADMINISTRATION OF STEROID HORMONES USING DIETHANOLAMIDES OF C12-Cw FATTY ACIDS AS PERMEATION
ENHANCERS
TECHNICAL FIELD The present invention is in the field of transdermal/transmucosal drug delivery. More particularly it concerns the use of dialkanolamides of fatty acids to enhance the transdermal administration of steroid hormones from a pressure sensitive adhesive matrix.
BACKGROUND ART Steroid hormones such as progestins, estrogens, and androgens have poor skin permeability. Therefore, in order to administer steroids transdermally or transmucosally at therapeutically effective rates through a reasonably sized area of skin or mucosa, it is necessary to use permeation enhancers in combination with the steroid.
A number of patents describe using permeation enhancers to increase the permeability of skin to steroid hormones. U.S. Patent Nos. 5,164,190 and 5,152,997 describe the use of a combination of subsaturation concentration and permeation enhancers to increase the flux of steroid drugs across skin. The exemplified enhancers include glycerol dioleate, glycerol monooleate, methyl laurate, oleic acid, and ethanol.
U.S. Patent Nos. 4,906,169 and 5,023,084 describe laminated composites for coadministering an estrogen and progestin transdermally. The estrogen is contained in a polymer layer and the progestin is contained in an underlying adhesive layer. Polyacrylic, polyisobutylene and silicone adhesives are mentioned. These patents also teach that a permeation enhancer can be included in the adhesive. "Saturated and unsaturated fatty acids and their esters, alcohols, monoglycerides, acetate, diethanolamides and N,N- dimethylamides . . ." are mentioned as enhancers. N-Decyl alcohol and capric acid are taught as preferred enhancers.
U.S. Pat. Nos. 4,818,540 and 5,296,230 also describe laminated composites for administering estrogens or progestins transdermally. In these composites the steroid is contained in a polymer layer. An adhesive layer underlies the polymer layer for affixing the composite to the skin. The patent teaches that the adhesive layer may contain permeation enhancers. The same enhancers that are taught in the ' 169 and '084 patents discussed above are also described in these patents.
U.S. Patent No. 5,314,694 discloses transdermal delivery devices but not a matrix type as disclosed herein where the drug and permeation enhancer is dissolved or dispersed in an adhesive which also serves to also affix the patch to the skin. The devices disclosed in U.S. Patent No. 5,314,694 are typical reservoir type patches containing the drug and/or enhancer in a reservoir and a separate adhesive layer affixes the reservoir is referred to the skin. The disclosure does not teach that a diethanolamide of a C[2-C]8 fatty acid is uniquely effective in enhancing the permeability of steroid hormones in a pressure sensitive adhesive matrix. PCT Publication WO 94/21262 describes the use of diethanolamides of fatty acids as permeation enhancers in combination with alprazolam. The diethanolamide and alprazolam are formulated in a nonadhesive polymeric reservoir.
U.S. Patent No. 5,252,334 teaches away from the use of permeation enhancers for the transdermal delivery of steroids. Even though various enhancers have been used previously to increase the rate at which steroids permeate through skin, there is still a need to find enhancers that permit even higher rates to be achieved. Better enhancers may allow the steroids, particularly testosterone, to be formulated in simple single matrix patches of relatively small size. This will enable less expensive patches that are more cosmetically acceptable.
DISCLOSURE OF THE INVENTION The present invention is based on applicants' discovery that diethanolamides of C12-C18 fatty acids are unexpectedly superior to other permeation enhancers with respect to enhancing the permeability of steroid hormones that are administered transdermally from a pressure sensitive adhesive matrix.
Accordingly, one aspect of the invention is a method of enhancing the transdermal administration of a steroid hormone from a pressure sensitive adhesive matrix comprising coadministering a diethanolamide of a C12-CI g fatty acid from said matrix.
Another aspect of this invention is the use of a highly pure composition of lauramide DEA for enhancing the transdermal administration of a steroid hormone from a pressure sensitive adhesive matrix.
Another aspect of the invention is a matrix for administering a steroid hormone transdermally comprising a mixture of: a) a pressure sensitive adhesive; b) a steroid hormone; and c) a diethanolamide of a C12-CJ 8 fatty acid.
Yet another aspect of the invention is a transdermal patch for administering a steroid hormone comprising a laminated composite of: a) a backing layer; and b) a matrix layer adapted to be placed in diffusional contact with skin or mucosa comprising a mixture of:
(i) a pressure sensitive adhesive;
(ii) a steroid hormone; and
(iii) a diethanolamide of a C12-C] g fatty acid.
MODES FOR CARRYING OUT THE INVENTION As used herein the term "transdermal" intends percutaneous and transmucosal (e.g. transbuccal) administration, i.e., passage of steroid through unbroken skin or mucosa into circulation.
Structurally "steroids" are the class of compounds all related through the cyclic nuclei they contain, i.e., a partly or completely hydrogenated 17 H- cyclopentanophenanthrene nucleus, the general formula for which is given below:
Steroid hormones can be natural, synthetic or semi-synthetic and can be classified according to their biological function as:
Progestagens, examples of which are (without limitation) progesterone, norethindrone acetate, norgestrel, levo-norgestrel, norethindrone, desogestrel, and gestodene.
Glucocorticoids, examples of which are (without limitation) corticol, corticone, hydrocortisone, betamethasone, dexamethasone, prednisone, predisolone and triamcinolone. Mineralocorticoids, examples of which are (without limitation) aldosterone and desoxycorticosterone.
Estrogens, examples of which are (without limitation) 17β estradiol and ethynyl estradiol.
Androgens, examples of which are (without limitation) testosterone, methyl testosterone, dihydrotestosterone and androsteinedione.
Cardiac glycosides, examples of which are (without limitation) digoxin and digitoxin.
Depending upon the condition being treated, a combination of steroid hormones may be administered. For instance, in providing hormone replacement therapy to females combination of an estrogen and a progestagen or an estrogen and an androgen (e.g., estradiol and testosterone) may be used.
A "therapeutically effective amount" of steroid intends an amount that provides the desired pharmacological result. These amounts are known by those skilled in the art. For instance, in the case of administering testosterone to males, the therapeutically effective amount will typically be about 1 to 10 mg/day.
As used herein the terms "permeation enhancement" and "enhancement,' are used interchangeably and describe an increase in the permeability of skin or mucosa to a steroid hormone. Permeation enhancement results in an increase in the flux of steroid through skin or mucosa. Skin flux may be measured in vitro using the procedure described in the examples, infra. A "skin/mucosa permeation enhancing amount" of diethanolamide of a
C12-Clg fatty acid is intended to mean an amount that results in steroid flux increase of at
least about 15%, more usually 30% to 300% relative to steroid flux in the absence of an enhancer.
As used herein the term "diffusional contact" means that the matrix is either directly or indirectly in contact with the skin or mucosa in a manner in which there is a diffusional pathway by which the steroid(s) can migrate from the matrix to the skin or mucosa.
The adhesive component of this invention are referred to as "matrix patches" containing for example a hydrocarbon solvent-compatible polyacrylate or a hydrocarbon solvent compatible adhesive. The adhesive reservoir or matrix can be a pressure-sensitive adhesive such as polyisobutylene, silicone, polyacrylate or other pressure sensitive adhesive acceptable for use as a matrix for a transdermal patch. The adhesive component of the matrix is preferably a hydrocarbon solvent-compatible polyacrylate, particularly a copolymer of 2-ethylhexyl acrylate and one or more other monomers such as vinyl acetate, acrylic acid, N-vinyl-2-pyrrolidone, 2-hydroxyethyl acrylate, butylacrylate, octylacrylate, styrene, methyl methacrylate, methacrylic acid, maleic acid, acrylamide and N-methylol acrylamide. Embodiments of such adhesives are available commercially from a number of sources, e.g. GELVA® adhesives from Monsanto Chemical Co., MORSTIK® adhesives from Morton Thiokol, Inc., Duro-Tak® adhesives from National Starch, and TSR adhesive from Sekisui. The diethanolamides that are employed as permeation enhancers in the invention are diethanolamides of C] 2-C] g fatty acids.
The fatty acid may be saturated or unsaturated and preferably has an even number of carbon atoms. Examples that are useful in the invention are the diethanolamides of lauric, tridecylic, myristic, pentadecylic, palmitic, stearic, palmitoleic, oleic and linoleic acids. A mixture of such diethanolamides may be used. Lauramide diethanol ("lauramide
DEA") is preferred. The diethanolamide component of the matrix will typically constitute 0.5% to 50% of the matrix, preferably 2.5% to 15%. Percentage of the components of the matrix are expressed on a dry weight basis. It has been found that commercially available lauramide DEA have verying degrees of purity. Substantially pure compositions of lauramide DEA are preferred. As used herein, "substantially pure" is defined as having a greater than about 75% lauramide DEA in the composition wherein "%" refers to area percent as determined by HPLC according to Example 9, infra.. More preferred is a
composition containing greater than about 85% lauramide DEA and most preferred is greater than about 90% lauramide DEA.
The steroid will normally constitute 0.1% to 30%, preferably 0.5% to 10% of the matrix. The matrix may be formulated by mixing the adhesive (which is typically obtained in solution), steroid(s), and diethanolamide in the appropriate proportions, casting the solution onto a substrate (e.g., a backing or release liner layer) and drying the cast layer of solution to drive off the solvent. The backing layer will typically comprise an occlusive polymer layer, combination of polymer layers, or combination of polymeric and metallic layers. Backing materials are well known in the transdermal patch art.
In addition to the matrix and backing, the transdermal patches of this invention will also include a release liner layer. Release liner materials are also well known in the transdermal patch art.
The invention is further illustrated by the following examples. These examples are not intended to limit the invention in any manner.
EXAMPLES Adhesive Matrix Preparation
Pressure sensitive polyacrylate adhesive matrix systems containing steroids and in some cases additional components were prepared from acrylate copolymer solutions in organic solvents as follows. First, the solid content of the adhesive solution was determined by placing a known weight of solution in a weighed aluminum dish and evaporating the solvents overnight in a 70°C convection oven. The solid adhesive content of the solution was calculated by dividing the adhesive solid weight after drying by the total solution weight. Second, a weighed quantity of adhesive solution was added to a glass bottle and the solid adhesive weight was calculated from the known solid fraction of the given adhesive solution. Steroid compounds and enhancers were weighed and mixed with the adhesive solution in the quantities necessary to achieve the desired dry matrix composition. The solution containing the adhesive copolymer and other components was mixed (usually overnight). Next, approximately 8 ml of the solution was dispensed on a silanized polyester release liner and cast with a 10 mil (0.25 mm) gap casting knife. The
cast was dried in a 70°C convection oven for 15 minutes to yield a dried film of approximately 2 mil (0.05 mm) thickness, then 3 mil (0.08 mm) thick polyethylene film was laminated onto the dried adhesive cast. These matrix systems were then used to conduct in vitro skin flux experiments as described below.
Skin Flux Studies In vitro skin flux studies were conducted using human cadaver epidermal membrane in modified Franz non-jacketed diffusion cells. The epidermal membrane (stratum corneum and epidermis) had been separated from the human cadaver whole skin (epidermal membrane and dermis) by the heat-separation method of Kligman and
Christopher (Arch. Dematol. 88:702 (1963)). This method involves the exposure of the full-thickness skin to water at 60 °C for a time period of 60 seconds. After this period, the epidermal membrane was gently peeled off the dermis and stored for later use in aluminum foil at -5 °C. Prior to skin permeation experiments, the silanized release liner was removed from the adhesive matrix system and the adhesive was affixed to the stratum corneum side of the thawed epidermal membrane which was then cut to an appropriate size and placed between the two halves of the diffusion cell with the stratum corneum facing the donor compartment. The receiver compartment was filled with an appropriate receiver medium to maintain sink conditions for the drug (e.g. 0.02% (w/v) sodium azide and 0.5% (w/v) Tween 40 for testosterone), and the diffusion cell was placed in a temperature controlled circulating water bath calibrated to maintain the surface temperature of the skin at 32 °C. The receiver compartment was constantly stirred by a magnetic stir-bar in the receiver compartment agitated by a magnetic stirring module placed under the water bath. At predetermined sampling intervals (usually 6, 12, and 24 hours), the entire contents of the receiver compartment were collected for drug quantitation and the receiver compartment was filled with fresh receiver solution, taking care to eliminate any air bubbles at the skin/solution interface.
The cumulative amount of drug permeated per unit area at any time t (Qt, μg/cm2) was determined from the following equation:
Q, γ£>¥.
^ A
where Ct (μg/cm3) is the concentration of the receiver compartment at sample time t (h), V is the volume of the receiver compartment of the diffusion cell (6.3 cm3), and A is the diffusional area of the cell (0.64 cm2).
Example 1
Testosterone is a naturally occurring steroid hormone which is administered transdermally for treatment of primary or secondary hypogonadism in males. Pressure sensitive adhesive matrix systems containing testosterone and lauramide diethanol (DEA) as an enhancer were compared to systems using lauric acid, lauryl alcohol, glycolic acid, and esters of lauric acid. All matrix systems were prepared in a medical-grade acrylic adhesive (Duro-Tak 87-2516) according to the methods described above and contained 3% by weight testosterone and 10% by weight enhancer. The results of skin flux experiments using these matrix systems are summarized in Tables 1-3.
Table 1
Daily In Vitro Permeation of Testosterone, Mean ± SD, [μg/(cm2*24h)]
All Systems are Duro-Tak 2516/Testosterone/Enhancer 87/3/ 10% (w/w)
Enhancer
Skin Characteristics Number of Diffusion Cells Lauramide DEA Lauric Acid Lauryl Alcohol Methyl Laurate
46 yr, Male RPL 4 52.1 ± 4.9 41.9 ± 2.1 40.8 ± 7.3 29.0 ± 2.8
66 yr, Male RPL 4 63.5 ± 14.0 39.1 ± 5.9 43.4 ± 5.8 27.0 ± 5.6
38 yr, Female LPL 4 49.1 ± 8.7 35.6 ± 5.8 39.0 ± 7.5 28.4 ± 6.7
65 yr, Male LPL 4 57.2 ± 6.1 57.6 ± 2.7 45.1 ± 5.9 46.7 ± 2.8
57 yr, Male LPL 4 68.8 ± 11.8 50.2 ± 5.5 80.2 ± 1 1.5 47.7 ± 5.3
63 yr, Male RPL 4 59.9 ± 2.4 37.4 ± 6.0 43.2 ± 1 1.9 26.8 ± 4.0
All Skins 24 58.4 ± 7.3 43.6 ± 8.6 48.6 ± 15.6 34.3 ± 10.1
Age, Sex, Site (RPL=Right Posterior Leg, LPL=Left Posterior Leg)
Table 2
Daily In Vitro Permeation of Testosterone, Mean ± SD, [μg/(cm2*24h)]
All Systems are Duro-Tak 2516/Testosterone/Enhancer 87/3/10% (w/w)
Enhancer Skin Characteristics Number of Lauramide Glycerol
Diffusion Cells DEA Monolaurate
46 yr, Male RPL 4 52.1 ± 4.9 37.6 ± 5.5
57 yr, Male LPL 4 68.8 ± 1 1.8 63.6 ± 4.1
63 yr, Male RPL 4 59.9 ± 2.4 46.7 ± 8.0
All Skins 12 60.3 ± 8.4 49.3 ± 13.2
* Age, Sex, Site (RPL=Right Posterior Leg, LPL=Left Posterior Leg)
Table 3
Daily In Vitro Permeation of Testosterone, Mean ± SD, [μg/(cm2*24h)]
Composition: Duro-Tak 2516/Testosterone/Enhancer % (w/w)
Skin Number No Enhancer Lauramide DEA Glycolic Acid Sorbitan Monooleate* Characteristics of 97/3/0 87/3/10 87/3/10 87/3/10
Diffusion Cells
63 yr, Male, RAL 4 28.3 ± 4.1 40.6 ± 4.3 35.0 ± 7.2 37.2 ± 3.9
65 yr, Male, RAL 4 35.2 ± 5.4 47.4 ± 2.7 26.1 ± 0.8 22.3 ± 3.3
38 yr, Female, LPL 4 15.5 ± 1.3 48.9 ± 6.5 23.4 ± 4.3 23.2 ± 1.0
All Skins 12 26.3 ± 10.0 45.7 ± 4.4 28.2 ± 6.1 27.6 ± 8.4
* Age, Sex, Site (RAL=Right Anterior Leg, LPL=Left Posterior Leg) ** Sorbitan monooleate=oleic acid ester of sorbitol (Arlacel® 80)
Table 4
Daily In Vitro Permeation of Testosterone, Mean ± SD, [μg/(cm2*24h)]
All Systems are Duro-Tak 2516/Testosterone/Enhancer 92/3/5% (w/w)
Enhancer
Skin Characteristics* Number of Lauramide Lauryl PCA* Diffusion Cells DEA
47 yr, Male, RPL 4 59.4 ± 9.0 44.0 ± 8.0 24 yr, Female, LPL 4 55.3 ± 5.6 38.5 ± 5.0 47 yr, Male, LPL 4 81.6 ± 4.7 48.6 ± 8.6
All skins 12 65.4 ± 14.2 43.7 ± 5.1
* Age, Sex, Site (RPL=Right Posterior Leg, LPL=Left Posterior Leg) ** Lauryl PCA=Lauryl alcohol, pyrrolidinone carboxylic acid ester (Laurydone^
The data in Tables 1 -4 show that a system using the diethanolamide derivative of lauric acid increases testosterone flux about 20% more than lauryl alcohol and lauric acid monoglyceride, 35% more than lauric acid, 50% more than the pyrrolidinone carboxylic acid ester (PC A) of lauryl alcohol, and about 70% more than the methyl ester of lauric acid, the sorbitan ester of oleic acid, and glycolic acid. These results indicate that fatty acid diethanolamide is unexpectedly superior at enhancing transdermal permeation of testosterone in a matrix system relative to α-hydroxy acids, fatty acids, fatty alcohols, fatty acid alkyl esters, fatty alcohol PCA esters, fatty acid monoglycerides, and fatty acid sorbitol esters— all of which are known in the art as transdermal permeation enhancers.
Example 2
Testosterone flux from matrix systems and hydroalcoholic gel systems was evaluated using Lauramide DEA and the methyl ester of lauric acid as enhancers. Hydroalcoholic solutions of 50 mg/ml testosterone in 50% by volume alcohol, USP (190 proof ethanol), 15% water, 30% glycerin, and 5% enhancer were prepared and mixed until the drug was fully dissolved. The solution was then gelled with 3% (w/w) carbomer (Pemulen TR-2) which was neutralized with 0.2 N sodium hydroxide to a pH of 4 to 5. The resulting gels were clear and visually homogeneous. Skin flux experiments for the hydroalcoholic gels were similar to those conducted with the adhesive matrix systems with the following exceptions. Prior to skin permeation experiments, the epidermal membrane was cut to an appropriate size and placed between the two halves of the diffusion cell with the stratum corneum facing the donor compartment. The receiver compartment was filled with 0.02% (w/v) sodium azide in water, and the diffusion cell was placed in a circulating water bath calibrated to maintain the temperature of the skin surface at 32°C, and allowed to hydrate overnight. After hydration, the sodium azide solution in the receiver compartment was removed and replaced with an appropriate solution to maintain sink conditions for testosterone through the duration of the experiment (0.02% (w/v) sodium azide and 0.5% (w/v) Tween 40 in water). A sample of the hydroalcoholic gel (75 μl) was then pipetted into a cavity created by placing a polyethylene washer over the stratum corneum surface. This cavity was covered with an occlusive polyethylene which was then clamped in place. Sampling of the
receiver solution at predetermined intervals was carried out as described above for the adhesive matrix skin flux experiments. Results from the in vitro skin flux experiments carried out with these gels are summarized in Table 5.
Adhesive matrices containing 3% by weight testosterone and 10% by weight enhancer were prepared in Duro-Tak 87-2516 as described previously. Skin flux experiments using the matrix systems on the same skin sources as those shown in Table 5 were conducted and the results from these experiments are shown in Table 6.
Table 5
Daily In Vitro Permeation of Testosterone, Mean ± SD, [μg/(cm2*24h)]
All Systems are Alcohol/Water/Glycerin/Enhancer 50/15/30/5% (v/v)
Enhancer Skin Characteristics* Number of Lauramide Diffusion Cells DEA Methyl Laurate
60 yr, Male, LPL 4 72.5 ± 19.1 224.8 ± 41.0
45 yr, Male, LPL 4 158.2 ± 52.0 424.1 ± 82.8
63 yr, Male, LPL 4 215.9 ± 40.0 313.6 ± 53.6
All Skins 12 148.9 ± 72.2 320.8 ± 99.9 * Age, Sex, Site (LPL=Left Posterior Leg)
Table 6
Daily In Vitro Permeation of Testosterone. Mean ± SD, [μg/(cm2*24h)j
All Systems are Duro-Tak 2516/Testosterone/Enhancer 92/3/5% (w/w)
Enhancer Skin Characteristics* Number of Lauramide
Diffusion Cells DEA Methvl Laurate
60 yr, Male, LPL 4 46.3 ± 6.8 24.1 ± 6.2
45 yr, Male, LPL 4 89.1 ± 16.5 48.4 ± 11.8
63 yr, Male, LPL 4 95.5 ± 8.3 52.7 ± 10.2
All Skins 12 76.9 ± 26.8 41.7 ± 15.4
* Age, Sex, Site (LPL=Left Posterior Leg)
The data in Table 5 show that in a hydroalcoholic gel lauramide DEA does not exhibit unusual flux enhancement relative to the methyl ester of lauric acid. The results in Table 6 confirm that the unusual flux enhancement for testosterone exhibited by lauramide
DEA relative to other known permeation enhancers occurs specifically in pressure sensitive adhesive matrix systems.
Example 3
Norethindrone acetate (NEA) is a female progestin steroid hormone. Adhesive matrix systems containing NEA and NEA with Lauramide DEA (Cyclomide® LE), sorbitan monolaurate (Arlacel® 20), or sorbitan monooleate (Arlacel® 80) as an enhancer were prepared as described above. The matrix systems consisted of 10% by weight NEA and 0 or 15% of the enhancer in Duro-Tak 80-1 194 or Duro-Tak 80-1054. The results of in vitro skin flux experiments on these matrix systems are summarized in Table 7 and Table 8.
Table 7
Daily In Vitro Permeation of NEA, Mean ± SD, [μg/(cm2*24h)]
Composition: Duro-Tak 80- 1 194/NEA/Enhancer Skin Number of No Enhancer Lauramide DEA Sorbitan Sorbitan Monooleate
Characteristics* Diffusion Cells 90/10 % (w/w) 75/10/15% (w/w) Monolaurate 75/10/15% (w/w)
75/10/15% (w/w)
67 yr, Male 4 5.4 ± 0.5 15.9 ± 1.7 13.2 ± 0.8 7.3 ± 0.4 76 yr, Male 4 4.7 ± 0.5 16.8 ± 0.6 9.1 ± 1.4 8.4 ± 4.2 All Skins 4.5 ± 0.7 15.5 ± 0.7 1 1.1 ± 2. 7.5 ± 0.7
Age, Sex
Table 8
Daily In Vitro Permeation of NEA, Mean ± SD, [μg/(cm2*24h)]
Composition: Duro-Tak 80-1054/NEA/Enhancer Skin Number of No Enhancer Lauramide DEA Sorbitan Sorbitan Monooleate
Characteristics* Diffusion Cells 90/10 % (w/w) 75/10/15% (w/w) Monolaurate 75/10/15% (w/w)
75/10/15% (w/w)
67 yr, Male 6.6 ± 1.5 18.3 ± 2.9 12.3 ± 1.2 9.8 ± 2.5 * Age, Sex
The data in Tables 7 and 8 indicate that use of lauramide DEA as an enhancer increases the flux of NEA from an adhesive matrix system about 3-fold relative to an adhesive matrix with NEA alone In addition, use of lauramide DEA as an enhancer increases the flux of NEA from 40 to 50% more on average than matrix systems containing sorbitan monolaurate and about 2-fold more than matrix systems containing sorbitan monooleate These results show that lauramide DEA is an unexpectedly superior permeation enhancer for NEA in a matrix system, showing significantly more flux enhancement than the two sorbitol esters tested-both of which are know permeation enhancers
Example 4
Estradiol is a naturally occurring female steroid hormone which is administered transdermally for female hormone replacement therapy Adhesive matrix systems containing estradiol and estradiol with lauramide DEA (Cyclomide® LE), sorbitan monolaurate (Arlacel® 20), or sorbitan monooleate (Arlacel® 80) as an enhancer were prepared as described above The matrix systems consisted of 4% by weight estradiol and 0 to 15% of the enhancer in a medical grade acrylic copolymer adhesive (Duro-Tak 80- 1194 or 80- 1070) The results of in vitro skin flux experiments on these matrix systems are summarized in Tables 9-11.
Table 9
Daily In Vitro Permeation of Estradiol, Mean ± SD, [μg/(cm2*24h)]
Composition Duro-Tak 80-1 194/Estradιol/Enhancer Skin Number of No Enhancer Lauramide DEA Sorbitan Sorbitan
Characteristics* Diffusion Cells 96/4 % (w/w) 81/4/15% (w/w) Monolaurate Monooleate 81/4/15% (w/w) 81/4/15% (w/w)
47 yr, Male 4 18 1 92 9 49 0 81 2
76 yr, Male 4 2 4 25 0 10 0 12 0
All Skins 8 10 3 ± 11 1 59 0 ± 48 0 29 5 ± 27 6 46 6 ± 48 9 * Age, Sex
Table 10
Daily In Vitro Permeation of Estradiol, Mean ± SD, [μg/(cm2*24h)]
Composition: Duro-Tak 80-1194/Estradiol/Enhancer Skin Number of No Enhancer Lauramide DEA Sorbitan Sorbitan Monooleate
Characteristics* Diffusion Cells 96/4 % (w/w) 81/4/15% (w/w) Monolaurate 81/4/15% (w/w)
81/4/15% (w/w)
47 yr, Male 4 25.6 90.9 49.5 52.6
76 yr, Male 4 6.9 26.6 6.6 20.1
All Skins 8 16.3 ± 13.2 58.8 ± 45.5 28.1 ± 30.3 36.4 ± 23.0
* Age, Sex
Table 11
Daily In Vitro Permeation of Estradiol, Mean ± SD, [μg/(cm2*24h)] Composition: Duro-Tak 80- 1070/Estradiol/Enhancer
Skin Number of No Enhancer Lauramide DEA Sorbitan Sorbitan
Characteristics Diffusion 96/4 % (w/w) 81/4/15% (w/w) Monolaurate Monooleate
Cells 81/4/15% (w/w) 81/4/15% (w/w)
47 yr, Male 4 18.6 70 48.7 34.1
76 yr, Male 4 5.8 19.6 5.3 8.4
All Skins 8 12.2 ± 9.1 44.8 ± 35.6 27.0 ± 30.7 21.3 ± 18.2
* Age, Sex
The results in Tables 9-11 demonstrate that lauramide DEA increases the flux about 4 to 5-fold relative to estradiol alone in an adhesive matrix system. The cumulative drug delivered from the system with lauramide DEA is typically 1.5 to 2 times greater than from systems using the know permeation enhancers, sorbitan monolaurate and sorbitan monooleate.
Example 5 The effect of fatty acid diethanolamides differing in the fatty acid group were evaluated in matrix systems containing various steroids. The fatty acid diethanolamides used as enhancers were lauramide DEA (Cyclomide® DEA), stearamide DEA
(Cyclomide® DS 280), or cocamide DEA (Alkamide® KD). Cocamide DEA is derived from coconut oil and contains palmitamide DEA. The systems consisted of 4% by weight estradiol or 3% by weight testosterone and 0 to 15% of the enhancer in Duro-Tak 87-2516 or Duro-Tak 80-1194. The results of in vitro skin flux experiments on these matrix systems are summarized in Tables 12 and 13.
Table 12
Daily In Vitro Permeation of Testosterone, Mean ± SD, [μg/(cm2*24h)]
Composition:
Duro-Tak 87-2516/Testosterone/Enhancer Skin Characteristics* Number of No Enhancer Lauramide DEA Cocamide DEA**
Diffusion Cells 97/3 % (w/w) 92/3/5 % (w/w) 92/3/5 % (w/w)
47 yr, Male, RPL 4 25.4 ± 4.2 57.1 ± 18.8 43.1 ± 7.9
47 yr, Male, LPL 4 38.2 ± 5.9 63.2 ± 4.9 61.9 ± 4.5
53 yr, Male, RPL 4 37.7 ± 6.1 60.3 ± 1.9 61.3 ± 4.6
12 33.7 ± 7.3 60.2 ± 3.1 55.4 ± 10.7
* Age, Sex, Site (RPL=Right Posterior Leg, LPL=Left Posterior Leg) ** Cocamide DEA=Coconut Fatty Acid, Diethanolamide
Table 13
Daily In Vitro Permeation of Estradiol, Mean ± SD, [μg/(cm2*24h)]
Number of Composition: Duro-Tak 80- 1 194/Estradiol/Enhancer Diffusion Cells No Enhancer Lauramide DEA Stearamide 96/4/0 % (w/w) 81/4/15 % (w/w) DEA** 81/4/15 % (w/w)
4 6.2 ± 0.7 9.4 ± 2.1 9.8 ± 6.5
** Stearamide DEA=Stearic Acid, Diethanolamide
The results above indicate that changes in the fatty acid component of the diethanolamides (within the C12 to C] 8 range) do not significantly change the flux enhancement observed in estradiol or testosterone skin flux.
Example 6 Transdermal flux enhancement of steroids using fatty acid diethanolamide was compared to flux enhancement using triethanolamine. Adhesive matrices containing 3% by weight testosterone as a model steroid and 5% by weight lauramide DEA or triethanolamine were prepared in Duro-Tak 87-2516, and the results of in vitro skin flux experiments using these matrices are shown in Table 14.
Table 14
Daily In Vitro Permeation of Testosterone, Mean ± SD, [μg/(cm2*24h)]
All Systems are Duro-Tak 2516/Testosterone/Enhancer 92/3/5% (w/w)
Enhancer Skin Characteristics* Number of Lauramide
Diffusion Cells DEA Triethanolamine
42 yr, Male RPL 4 75.4 ± 7.9 33.2 ± 2.4
53 yr, Male LPL 4 40.4 ± 6.9 13.7 ± 1.6
All Skins 8 57.9 ± 24.7 23.5 ± 13.8
* Age, Sex, Site (RPL=Right Posterior Leg, LPL=Left Posterior Leg)
The data in Table 14 provide evidence that the fatty acid component of alkanoic acid diethanolamides is required for transdermal flux enhancement of steroid molecules from pressure sensitive adhesives.
Example 7 Transdermal flux enhancement of testosterone and estradiol from a matrix system was evaluated using fatty acid amides with differing amine components. Adhesive matrices containing 3% by weight testosterone or 1.5% by weight estradiol were prepared in an acrylic copolymer adhesive (Duro-Tak 87-2516, or 80-1070). The fatty acid amides tested were lauramide DEA (Alkamide® LE), cocamide MEA (Alkamide® CME), lauramide MEA (Alkamide® L-203), lauramide MIA (Alkamide® LIPA/C), lauric acid
N,N-dimethylamide, and lauric acid N,N-diethylamide. Results from in vitro flux experiments on these matrix systems are summarized in Tables 15-17.
Table 15
Daily In Vitro Permeation of Testosterone, Mean ± SD, [μg/(cm2*24h)]
All Systems are Duro-Tak 2516/Testosterone/Enhancer 92/3/5% (w/w)
Enhancer
Skin Number of Lauramide Cocamide Lauramide Lauramide Characteristics* Diffusion Cells DEA MEA** MEA** MIA**
42 yr, Male, RPL 4 75.4 ±7.9 50.6 ± 1.7 52.0 ±11.6 50.2 ±10.0 53 yr, Male, LPL 4 40.4 ±6.9 22.2 ±3.9 18.2 ±5.2 25.5 ±6.0
All Skins 8 57.9 ±24.7 36.4 ±20.1 35.1 ±23.9 37.9 ±17.5
* Age, Sex, Site (RPL=Right Posterior Leg, LPL=Left Posterior Leg)
** Cocamide MEA=Coconut Fatty Acid, Monoethanolamide; Lauramide MEA=Lauric
Acid, Monoethanolamide; Lauramide MIA=Lauric Acid, Monoisopropylamide
Table 16
Daily In Vitro Permeation of Estradiol, Mean ± SD, [μg/(cm2*24h)]
All Systems are Duro-Tak 1070/Estradiol/Enhancer 93.5/1.5/5% (w/w)
Number of Enhancer
Skin Characteristics* Diffusion Lauramide Lauric Acid
Cells DEA N,N- -Dimethylamide
69 yr, Female, NA 4 15.6 ±1.0 7.8 ±0.5
64 yr, Female, NA 4 4.8 ±0.9 5.1 ±1.7
43 yr, Female, NA 4 15.3 ±1.4 8.4 ±0.7
69 yr, Female, NA 4 14.9 ±3.2 5.5 ±1.6
61 yr, Male, LAL 4 13.2 ± 1.6 9.4 ± 1.9
55 yr, Female, LPL 4 3.9±0.1 2.3 ±0.3
All Skins 24 11.3 ±5.4 6.4 ±2.6
* Age, Sex, Site (LAL=Left Anterior Leg, LPL=Left Posterior Leg, NA=Site information not available)
Table 17
Daily In Vitro Permeation of Estradiol, Mean ± SD, [μg/(cm2*24h)]
All Systems are Duro-Tak 1070/Estradiol/Enhancer 93.5/1.5/5% (w/w)
Number of Enhancer Skin Characteristics* Diffusion Lauramide Lauric Acid
Cells DEA N,N-Diethylamide
69 yr, Female, NA 4 14.9 ± 3.2 5.5 ± 1.6
61 yr, Male. LAL 4 13.2 ± 1.6 9.4 ± 1.9
55 yr, Female, LPL 4 3.9 ± 0.1 2.3 ± 0.3
All Skins 24 1 1.3 ± 5.4 4.8 ± 2.5
* Age, Sex, Site (LAL=Left Anterior Leg, LPL=Left Posterior Leg, NA=Site information not available)
The results in Tables 15-17 show that fatty acid diethanolamides are significantly superior to the other fatty acid amides tested at increasing the transdermal flux of testosterone and estradiol. Monoethanolamides, monoisopropanolamides, and dimethylamides and diethylamides do not exhibit the same degree of flux enhancement for steroid compounds.
Example 8
Transdermal flux enhancement of non-steroidal compounds, oxybutynin and diclofenac, from a matrix system was evaluated using Lauramide DEA and several other known permeation enhancers. Adhesive matrices containing oxybutinin or diclofenac were prepared in an acrylic copolymer adhesive (Seksui TSR). The matrices contained 10% (w/w) of one of the following enhancers lauramide DEA (Alkamide® LE), glycerol monolaurate , lauric acid methyl ester, or lauryl alcohol. Results from in vitro flux experiments on these matrix systems are summarized in Tables 18 and 19.
Table 18
Daily In Vitro Permeation of Oxybutynin, Mean ± SD, [μg/(cm2*24h)]
All Systems are TSR/Oxybutynin/Enhancer 70/20/10% (w/w)
Enhancer
Skin Number of Lauramide Glycerol Methyl Lauryl Characteristics* Diffusion DEA Monolaurate Laurate Alcohol Cells
60 yr, Male, RAL 4 22.8 ± 7.8 56.8 ± 11.9 39.9 ± 5.9 40.5 ± 4.3 68 yr, Male, LPL 4 19.8 ± 6.9 30.2 ± 2.6 22.5 ± 3.3 45.0 ± 9.0 57 yr, Male, LPL 4 21.2 ± 4.3 47.8 ± 6.7 27.1 ± 3.8 30.1 ± 1.4
All Skins 12 21.3 ± 1.5 44.9 ± 13.5 29.8 ± 9.0 38.5 ± 7.7
* Age, Sex, Site (RPL=Right Posterior Leg, RAL=Right Anterior Leg)
Table 19
Daily In Vitro Permeation of Diclofenac, Mean ± SD, [μg/(cm2*24h)]
All Systems are TSR/Diclofenac/Enhancer 97/10/3% (w/w)
Enhancer
Skin Number of Lauramide Glycerol Methyl Lauryl
Characteristics* Diffusion DEA Monolaurate Laurate Alcohol Cells
64 yr, Male, RPL 4 9.1 ± 0.8 lO.O ± 1.2 14.2 ± 1.2 8.4 ± 1.1
55 yr, Male, RPL 4 8.5 ± 1.3 1 1.0 ± 3.2 28.4 ±1 1.2 17.8 =b 3.3
47 yr, Male, LAL 4 24.6 ± 1.7 22.0 ± 4.3 21.3 ± 3.6 31.0 ± 3.4
All Skins 12 14.1 ± 9.1 14.3 ± 6.7 21.3 ± 7.1 19.1 ± 1.3
* Age, Sex, Site (RPL=Right Posterior Leg, LAL=Left Anterior Leg)
Oxybutynin permeation from the system containing Lauramide DEA is lower than the permeation from systems containing glycerol monolaurate, methyl laurate, or lauryl alcohol as enhancers. These results suggest that the unusual transdermal flux enhancement of alkanoic acid diethanolamides is specific to steroidal compounds.
Diclofenac permeation from the system containing lauramide DEA is similar to or lower than the permeation from systems containing glycerol monolaurate methyl laurate, or lauryl alcohol as enhancers. These results are further evidence that the unusual
transdermal flux enhancement of alkanoic acid diethanolamides is specific to steroidal compounds.
Example 9
Applicants have discovered that compositions containing highly pure formulations of lauramide DEA unexpectedly enhances the transdermal flux of drugs, including steroids. Table 20 lists the commercially available lauramide DEA formulations that were evaluated for purity.
Table 20
Table 21 shows the results of HPLC analysis of the above noted commercially available lauramide DEA formulations. A (3.0 x 150) mm column C-18 Symmetry (available from Waters Corporation, Milford MA, USA) with Symmetry guard was run at ambient temperature flow rate of 1.2 ml/minute, detection λ at 210 nm. The mobile phase of the column was a 40:60 (v:v) wateπacetonitrile solution.
Table 21
HPLC Area Fractions Showing Purity of Lauramide DEA Materials.
Transdermal flux enhancement of testosterone from a matrix system was evaluated using lauramide DEA of low purity (Alkamide LE (Rhone-Poulenc)) and high purity
(Prophan (Sanyo Kasei)). Adhesive matrices containing 6% by weight testosterone and 7.5% lauramide DEA were prepared in an acrylic copolymer adhesive 86.5% (TSR Adhesive). Table 22 reports the results of invitro skin flux experiments on these matrices.
Table 22
In Vitro Permeation Enhancement of Testosterone in a Matrix System Using High-Purity Lauramide DEA.
This difference in means is significant (p<0.05, 2-Way ANOVA).
Testosterone permeation from the systems containing greater than 85% pure lauramide DEA is, in most instances, greater than permeation from systems containing less pure (i.e., less than 75%) lauramide DEA.
Modifications of the above-described modes for carrying out the invention that are obvious to those of skill in the field of transdermal drug delivery are intended to be within the scope of the following claims.