Lipid prodrugs of neurosteroids

Abstract

The present invention provides lymphatic system-directing lipid prodrugs, pharmaceutical compositions thereof, methods of producing such prodrugs and compositions, as well as methods of improving the bioavailability or other properties of a therapeutic agent that comprises part of the lipid prodrug. The present invention also provides methods of treating a disease, disorder, or condition such as those disclosed herein, comprising administering to a patient in need thereof a disclosed lipid prodrug or a pharmaceutical composition thereof.

We claim: 
     
         1 . A compound of formula I: 
       
         
           
           
               
               
           
         
         or a pharmaceutically acceptable salt thereof, wherein:
 R 1  and R 2  are each independently hydrogen, an acid-labile group, a lipid, or —C(O)R 3  each R 3  independently is a saturated or unsaturated, straight or branched, optionally substituted C1-37 hydrocarbon chain; 
 X is —O—, —NR—, or —S—; 
 each R independently is hydrogen or an optionally substituted group selected from C1-6 aliphatic, a 3-8 membered saturated or partially unsaturated monocyclic carbocyclic ring, phenyl, an 8-10 membered bicyclic aromatic carbocyclic ring, a 4-8 membered saturated or partially unsaturated monocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur, a 5-6 membered monocyclic heteroaromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur, or an 8-10 membered bicyclic heteroaromatic ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, and sulfur; 
 Y is —C(O)—, —C(NR)—, or —C(S)—; 
 L is a bivalent, saturated C3-30 hydrocarbon chain optionally substituted with 1, 2, 3, or 4 R 4  groups, wherein 0-4 methylene units of L are independently replaced by —O—, —OC(O)—, —C(O)O—, or —C(O)— and 1 methylene unit of L is optionally replaced with -M−: or 
 L is 
 
       
       
         
           
           
               
               
           
         
         
            wherein either the right-hand side or left-hand side of L is attached to  ; 
           each R 4  and R 5  independently is hydrogen, deuterium, halogen, —CN, —OR, —NR 2 , —SR, a 3-8 membered saturated or partially unsaturated monocyclic carbocyclic ring, phenyl, an 8-10 membered bicyclic aromatic carbocyclic ring, a 4-8 membered saturated or partially unsaturated monocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur, a 5-6 membered monocyclic heteroaromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur, or an 8-10 membered bicyclic heteroaromatic ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, and sulfur, or a C1-6 aliphatic group optionally substituted with —CN, —OR, —NR 2 , —SR, a 3-8 membered saturated or partially unsaturated monocyclic carbocyclic ring, phenyl, an 8-10 membered bicyclic aromatic carbocyclic ring, a 4-8 membered saturated or partially unsaturated monocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur, a 5-6 membered monocyclic heteroaromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur, or an 8-10 membered bicyclic heteroaromatic ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, and sulfur, or the C1-6 aliphatic is optionally substituted with 1, 2, 3, 4, 5, or 6 deuterium or halogen atoms; or 
           two instances of R 4  or R 5  attached to the same carbon atom, taken together with the carbon atom to which they are attached, form a 3-6 membered spirocyclic saturated monocyclic carbocyclic ring or 3-6 membered spirocyclic saturated heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur; 
           M- is a self-immolative group; 
           n is 0-18; 
           each m independently is 0-6; and 
              is a therapeutic agent selected from a pregnane neurosteroid or an analogue or prodrug thereof. 
         
       
     
     
         2 . The compound according to  claim 1 , wherein R 1  and R 2  are —C(O)R 3 . 
     
     
         3 . The compound according to  claim 2 , wherein each R 3  independently is a saturated or unsaturated, unbranched C1-37 hydrocarbon chain. 
     
     
         4 . The compound according to  claim 1 , wherein each of R 1  and R 2  independently is a fatty acid acyl group. 
     
     
         5 . The compound according to  claim 4 , wherein each of R 1  and R 2  are the same and are either the acyl group of octanoic acid or oleic acid. 
     
     
         6 . The compound according to  claim 1 , wherein X is —O—. 
     
     
         7 . The compound according to  claim 1 , wherein Y is —C(O)—. 
     
     
         8 . The compound according to  claim 1 , wherein L is a bivalent saturated C3-15 hydrocarbon chain optionally substituted with 1, 2, 3, or 4 R 4  groups, wherein 1-2 methylene units of L are independently replaced by —O—, —OC(O)—, —C(O)O—, or —C(O)— and 1 methylene unit of L is optionally replaced with -M−. 
     
     
         9 . The compound according to  claim 1 , wherein L is 
       
         
           
           
               
               
           
         
         wherein either the right-hand side or left-hand side of L is attached to  . 
       
     
     
         10 . The compound according to  claim 9 , wherein L is 
       
         
           
           
               
               
           
         
       
     
     
         11 . The compound according to  claim 9 , wherein L is 
       
         
           
           
               
               
           
         
       
     
     
         12 . The compound according to  claim 1 , wherein -M- is selected from one of the following: 
       
         
           
           
               
               
           
         
         wherein each R 6  independently is selected from hydrogen, deuterium, C1-5 aliphatic, halogen, or —CN; 
         each R 7  independently is selected from hydrogen, deuterium, halogen, —CN, —OR, —NR 2 , —NO 2 , —SR, a 3-8 membered saturated or partially unsaturated monocyclic carbocyclic ring, phenyl, an 8-10 membered bicyclic aromatic carbocyclic ring, a 4-8 membered saturated or partially unsaturated monocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur, a 5-6 membered monocyclic heteroaromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur, or an 8-10 membered bicyclic heteroaromatic ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, and sulfur, or a C1-6 aliphatic group optionally substituted with —CN, —OR, —NR 2 , —SR, a 3-8 membered saturated or partially unsaturated monocyclic carbocyclic ring, phenyl, an 8-10 membered bicyclic aromatic carbocyclic ring, a 4-8 membered saturated or partially unsaturated monocyclic heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur, a 5-6 membered monocyclic heteroaromatic ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur, or an 8-10 membered bicyclic heteroaromatic ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, and sulfur, or the C1-6 aliphatic is optionally substituted with 1, 2, 3, 4, 5, or 6 deuterium or halogen atoms; 
         each Z 1  independently is selected from —O—, —NR—, and —S—; 
         each Z 2  independently is selected from —O—, —NR—, —S—, —OC(O)—, —NRC(O)O—, and —OC(O)NR—; 
         each Z 3  independently is selected from ═N— and ═C(R 7 )—; and 
         each Z 4  independently is —O—, —NR—, —S—, —C(R 6 ) 2 —, or a covalent bond. 
       
     
     
         13 . The compound according to  claim 12 , wherein -M- is selected from 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
     
     
         14 . The compound according to  claim 13 , wherein -M- is selected from 
       
         
           
           
               
               
           
         
       
     
     
         15 . The compound according to  claim 14 , wherein -M- is selected from 
       
         
           
           
               
               
           
         
       
     
     
         16 . The compound according to  claim 1 , wherein each R 4  independently is hydrogen, deuterium, halogen, —CN, or C 1-4  aliphatic optionally substituted with 1, 2, 3, 4, 5, or 6 deuterium or halogen atoms; or two instances of R 4  attached to the same carbon atom, taken together with the carbon atom to which they are attached, form a 3-6 membered spirocyclic saturated monocyclic carbocyclic ring or 3-6 membered spirocyclic saturated heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur. 
     
     
         17 . The compound according to  claim 1 , wherein each R 5  independently is hydrogen, deuterium, halogen, —CN, or C 1-4  aliphatic optionally substituted with 1, 2, 3, 4, 5, or 6 deuterium or halogen atoms; or two instances of R 5  attached to the same carbon atom, taken together with the carbon atom to which they are attached, form a 3-6 membered spirocyclic saturated monocyclic carbocyclic ring or 3-6 membered spirocyclic saturated heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur. 
     
     
         18 . The compound according to  claim 1 , wherein each R 4  and R 5  independently is hydrogen or C1-4 alkyl optionally substituted with 1, 2, 3, 4, 5, or 6 deuterium or halogen atoms. 
     
     
         19 . The compound according to  claim 1 , wherein   is selected from allopregnanolone, pregnanolone, pregnenolone, ganaxolone, alfaxalone, 3β-dihydroprogesterone, isopregnanolone, epipregnanolone, or 21-hydroxyallopregnanolone. 
     
     
         20 . The compound according to  claim 19 , wherein   is allopregnanolone. 
     
     
         21 . The compound according to  claim 1 , wherein   is an excitatory neurosteroid. 
     
     
         22 . The compound according to  claim 1 , wherein the compound is selected from one of the following: 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         or a pharmaceutically acceptable salt thereof. 
       
     
     
         23 . The compound according to  claim 1 , wherein the compound is selected from 
       
         
           
           
               
               
           
         
       
     
     
         24 . A pharmaceutically acceptable composition comprising a compound according to  claim 1 , and a pharmaceutically acceptable excipient, carrier, adjuvant, or vehicle. 
     
     
         25 . The pharmaceutically acceptable composition according to  claim 24 , further comprising an additional therapeutic agent. 
     
     
         26 . The pharmaceutically acceptable composition according to  claim 24 , wherein the composition is formulated for oral administration. 
     
     
         27 . A method of treating or preventing a disease, disorder, or condition in which an increased level of a pregnane neurosteroid is beneficial, or a disease, disorder, or condition caused by a deficiency in a pregnane neurosteroid, comprising administering to a subject in need thereof an effective amount of a compound according to  claim 1 . 
     
     
         28 . A method of treating a disease, disorder, or condition caused by deficient activation of GABA A , comprising administering to a subject in need thereof an effective amount of a compound according to  claim 1 . 
     
     
         29 . The method of  claim 27 , wherein the disease, disorder, or condition is selected from post-partum depression, depression, major depressive disorder, bipolar disorder, a mood disorder, anxiety, post-traumatic stress disorder (PTSD), premenstrual dysphoric disorder (PMDD), premenstrual syndrome, generalized anxiety disorder, seasonal affective disorder (SAD), social anxiety, memory loss, poor stress tolerance, Niemann-Pick disease type C or an associated neurological or physical symptom, epilepsy, essential tremor, an epileptiform disorder, NMDA hypofunction, migraine, status epilepticus, a sleep disorder, Fragile X Syndrome, depression induced by a 5 alpha reductase inhibitor, PCDH19 female pediatric epilepsy, sexual dysfunction, Parkinson's disease, or Alzheimer's disease. 
     
     
         30 . The method of  claim 29 , wherein the disease, disorder or condition is epilepsy or an epileptic disorder.