Contraceptive Use of Triterpenoids

Abstract

Disclosed are systemic and intravaginal non-hormonal contraceptives comprising a spermicidal triterpenoid. The contraceptive may be in the form of a foam, cream or gel, or in unit form of a pill, vaginal contraceptive film (VCF), suppository, sponge, transdermal or hypodermal patches or a slow release intravaginal device or intrauterine device such as a drug-impregnated silicone elastomer vaginal ring or polymeric IUD.

Claims

1. A pharmaceutical composition comprising a spermicidal plant triterpenoid formulated and configured as an intravaginal or systemic contraceptive.

2. The composition of claim 1 formulated and configured in form of a vaginal contraceptive foam, cream or gel, and the triterpenoid is in a predetermined, unit or multi-unit dosage effective for contraception.

3. The composition of claim 1 formulated and configured in unit form of a vaginal contraceptive film (VCF), suppository, sponge, slow release intravaginal devices or intrauterine devices such as drug-impregnated silicone elastomer vaginal rings or polymeric IUDs, and the triterpenoid is in a predetermined, unit dosage effective for contraception.

4. The composition of claim 1 formulated and configured in form of a systemic contraceptive that is a pill, transdermal or hypodermal patch, and the triterpenoid is in a predetermined, unit or multi-unit dosage effective for contraception.

5. The composition of claim 1, wherein the triterpenoid inhibits human tubular fluid, progesterone (P4)- or pregnenolone sulfate (PregS)-induced activation of the principal human sperm calcium channel, CatSper, such as indicated by calcium imaging or recording of inward monovalent currents (I.sub.CatSper) through the channel with electrophysiology or calcium imaging.

6. The composition of claim 1, wherein the triterpenoid inhibits P4- or PregS-induced human sperm hyperactivation, sperm motility or fertilization.

7. The composition of claim 1 wherein the triterpenoid is a pentacyclic 11-unsubstituted (11-H) triterpenoid.

8. The composition of claim 2 wherein the triterpenoid is a pentacyclic 11-unsubstituted (11-H) triterpenoid.

9. The composition of claim 3 wherein the triterpenoid is a pentacyclic 11-unsubstituted (11-H) triterpenoid.

10. The composition of claim 4 wherein the triterpenoid is a pentacyclic 11-unsubstituted (11-H) triterpenoid.

11. The composition of claim 1 wherein the triterpenoid comprises a ring structure of lupeol.

12. The composition of claim 2 wherein the triterpenoid comprises a ring structure of lupeol.

13. The composition of claim 3 wherein the triterpenoid comprises a ring structure of lupeol.

14. The composition of claim 4 wherein the triterpenoid comprises a ring structure of lupeol.

15. The composition of claim 1 wherein the triterpenoid is lupeol.

16. The composition of claim 2 wherein the triterpenoid is lupeol.

17. The composition of claim 3 wherein the triterpenoid is lupeol.

18. The composition of claim 4 wherein the triterpenoid is lupeol.

19. A method of using a composition of claim 1, comprising delivering the composition to a vagina, or delivering the composition via an oral route, transdermal or hypodermal route.

20. A method of inhibiting sperm motility comprising contacting the sperm with an effective amount of a spermicidal plant triterpenoid.

Description

[0021] Description of Particular Embodiments and Delivery Methods of the Invention

[0022] Unless contraindicated or noted otherwise, in these descriptions and throughout this specification, the terms a and an mean one or more, the term or means and/or and polynucleotide sequences are understood to encompass opposite strands as well as alternative backbones described herein.

[0023] The examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. All publications, patents, and patent applications cited herein, including citations therein, are hereby incorporated by reference in their entirety for all purposes.

[0024] Embodiments to deliver active agent(s) include but are not limited to vaginal rings, pills and transdermal patches that release the active agent(s) at a predefined rate.

[0025] In embodiments:

[0026] the delivery method is in the form of a vaginal ring: A vaginal ring may be a flexible device measuring 20-80 mm in diameter and 240 mm in thickness. The ring may consist of poly(ethylene-co-vinyl acetate), ethylene vinyl acetate copolymer, or silicone elastomer that contains crystals of either pristimerin, lupeol or both, This ring contains sufficient amount of active compound(s) to maintain stable blood concentrations for about 5 weeks releasing between and 100 mcg of active compound(s)/24 hours, but is intended to be used for 3 weeks followed by a ring-free week.

[0027] the delivery method is in the form of a pill: The pill may contain sufficient concentrations of active compound(s) (e.g. pristimerin, lupeolor both) to maintain stable blood concentrations by releasing between 1 to 100 mcg of active compound(s)/24 hours. The pill may be used for long-term or on-demand contraception. For long-term contraception, the pill is intended to be used daily for 3 weeks followed by a pill-free week. For on-demand or emergency contraception, the pill is intended to be used daily up to 5 days after vaginal intercourse during the fertile period of the menstrual cycle. inactive compounds may comprise any combination of dyes, water, corn starch, magnesium stearate, lactose, croscarmellose sodium, polyethylene glycol and titanium dioxide. The purpose of these ingredients is to stabilize the composition of the pill and to assist in dissolving the active compound(s) in the gastrointestinal tract.

[0028] The following examples demonstrate that triterpenoids can prevent hormone-induced or fallopian tubal fluid-induced activation of the sperm calcium channel, avert sperm hyperactivation, decrease sperm motility and inhibit sperm fertility.

[0029] Plant triterpenoids including pristimerin and lupeol significantly reduce the activation of CatSper by either P4 or PregS. 2-AG hydrolysis by monoacyl lipases, such as ABHD2, is required for CatSper activation. The plant triterpenoid pristimerin was reported to inhibit the activity of related monoacylglycerol lipase (MAGL) (9). If pristimerin can also inhibit ABHD2, then sperm exposure to this compound should prevent CatSper activation by P4 or PregS. To test this hypothesis, human spermatozoa were stimulated with pristimerin, followed by exposure to either a mixture of pristimerin and P4, or to a mixture of pristimerin and PregS. In these experiments we analyzed inward monovalent currents through CatSper (I.sub.CatSper) of human sperm. Electrophysiology recordings were performed as described in (14). The mere presence of pristimerin did not affect basal I.sub.CatSper, which indicates that pristimerin did not target the channel directly. However, co-application of pristimerin with P4 or PregS significantly reduced CatSper activation. Compared to stimulation with P4 or PregS alone, the I.sub.CatSper stimulation was reduced by 63% (pristimerin and P4) and by 48% (pristimerin and PregS) (7).

[0030] Another pharmacologically active plant triterpenoid, which affects sperm functions when orally administered to rats, is lupeol (8). Lupeol is similar in structure to steroid hormones. Comparable to pristimerin, lupeol alone did not affect basal I.sub.CatSper. However, administration of lupeol with P4 or PregS led to an even stronger inhibition of I.sub.CatSper than pristimerin. Compared to CatSper stimulation elicited by P4 or PregS alone, CatSper currents were reduced by 71% and 68%, respectively, in combination with P4 or PregS (7). We have also shown with calcium imaging that pristimerin dose-dependently blocked steroid-activated CatSper activation in human spermatozoa.

[0031] Pristimerin and lupeol decrease sperm hyperactivation in the presence of P4. Hyperactivated sperm motility is characterized by a highly asymmetrical bending of the sperm tail due to a CatSper-mediated rise in flagellar calcium concentration (15). Curvilinear velocity (VCL) is the average velocity of the sperm head through the sperm trajectory, which increases during capacitation. A CatSper-mediated calcium rise promotes hyperactivation and makes the sperm trajectory less linear, which results in an increase of VCL. Capacitation increases CatSper activity, which results in a higher percentage of sperm with hyperactivated motility. Thus, capacitated spermatozoa tend to have higher VCL values than non-capacitated. Since both P4 and PregS activate CatSper, while pristimerin and lupeol inhibit it, we explored whether VCL values of human sperm are affected in the presence of plant triterpenoids or steroid hormones. As expected, neither of the compounds changed VCL values of non-capacitated sperm cells. In capacitated spermatozoa, P4 stimulation increased VCL by 12%, comparable to numbers reported by others (3, 16), but VCL values remained unchanged in the presence of PregS, pristimerin or lupeol alone (7). When spermatozoa were stimulated with P4+pristimerin or P4+lupeol, VCL values were reduced by 39% and 48%, respectively, in comparison to VCL values obtained in the presence of P4, and the reduced VCL values were comparable to those of non-capacitated cells. Stimulating capacitated sperm with PregS in combination with pristimerin or lupeol decreased VCL by 18% and 9%, respectively, compared to sperm, which were treated with PregS alone. VCL values of non-capacitated sperm remained unchanged under such conditions. Since CatSper is not only required for hyperactivation but also for basal motility, we sought to determine whether pristimerin and lupeol also affect sperm motility. The number of both capacitated and non-capacitated motile spermatozoa remained unchanged when stimulated with either compounds. However, when P4 was co-applied with pristimerin or lupeol the percentage of motile capacitated sperm decreased significantly by 19%, respectively, whereas the values of non-capacitated cells did not change. Co-stimulation with PregS and pristimerin or lupeol, however, did not result in a significant reduction of motile capacitated or non-capacitated sperm. These results indicate that triterpenoids like pristimerin and lupeol have the capacity to significantly reduce sperm hyperactivation by blocking the P4-mediated activation of CatSper.

[0032] Intravaginal spermicidal triterpenoid formulations

[0033] Formulations encompass a representative spermicidal triterpenoid, including pristimerin, lupeol or both compounds (e.g. 50:50 w/w combinations).

[0034] A) Intravaginal spermicidal triterpenoid aerosol foam (canister with applicator); active ingredient: spermicidal triterpenoid, 10% inactive ingredients: benzoic acid, cellulose gum, acetyl alcohol, fragrance, glacial acetic acid, methylparaben, phosphoric acid, polyvinyl alcohol, propellant A-31, propylene glycol, purified water, sorbic acid, stearamidoethyl diethyl amine, stearic acid.

[0035] B) Intravaginal spermicidal triterpenoid gel (prefilled applicators, 0.1 oz (2.6 g) each; active ingredients: spermicidal triterpenoid, 5%; inactive ingredients: lactic acid, methylparaben, povidone, propylene glycol, water (purified), sodium carboxy methyl cellulose, sorbic acid, sorbitol

[0036] C) Vaginal spermicidal triterpenoid contraceptive sponge; active ingredients: in each sponge: spermicidal triterpenoid (1000 mg); inactive ingredients: benzoic acid, citric acid, sodium dihydrogen citrate, sodium metabisulfite, sorbic acid, water in a polyurethane foam sponge.

[0037] D) Vaginal spermicidal triterpenoid contraceptive film; active ingredient: spermicidal triterpenoid (30%); inactive ingredients: glycerin, polyvinyl alcohol, purified water.

[0038] References

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