Metabolic pathways of the topical glucocorticoid budesonide in man

The metabolic pathways of budesonide[(22RS)-16 alpha, 17 alpha-butylidenedioxy-11 beta, 21-dihydroxypregna-1,4-diene-3,20-dione] in human liver 9000g supernatant fraction were studied. A comparison was made between the in vitro metabolite pattern and the metabolite pattern in plasma obtained after iv administration of tritiated budesonide to man. No qualitative difference could be found, which indicates that the in vitro model is useful to predict results in vivo. The two major metabolites formed in vitro were identified by HPLC and mass spectrometry as 6 beta-hydroxybudesonide and 16 alpha-hydroxyprednisolone. Loss of the acetal group was not observed when desonide (11 beta,21-dihydroxy-16 alpha,17 alpha-isopropylidenedioxy-pregna-1,4-diene-3,20-dione) was incubated with human liver 9000g supernatant fraction. Neither could 16 alpha-hydroxyprednisolone be detected after incubation of the (22S)-epimer of budesonide with the same medium. The cleavage of the acetal moiety is therefore suggested to be the result of a substrate-selective metabolic pathway.     

Liver metabolism of budesonide in rat, mouse, and man. Comparative aspects

The metabolism of budesonide, (22RS)-16 alpha, 17 alpha-butylidenedioxy-11 beta,21-dihydroxypregna-1,4-diene- 3,20-dione, was studied in the 9000g supernatant fraction of livers from rat, mouse, and man. The two budesonide C-22 epimers produced different metabolites. This was explained by substrate-selective oxidation of the nonsymmetric 16 alpha, 17 alpha-acetal substituent. Epimer 22R gave 16 alpha-hydroxyprednisolone, while epimer 22S produced a metabolite tentatively identified as 23-hydroxybudesonide. Otherwise, budesonide followed the general metabolic pathways reported for synthetic glucocorticoids. Thus, oxidative metabolism predominated, 6 beta-hydroxybudesonide and delta 6-budesonide being identified in all investigated species. Reductive metabolism, giving 4,5 beta-dihydrobudesonide and 3,4,5 beta-tetrahydrobudesonide, was most pronounced in the rat. Rates and routes of budesonide metabolism were most similar in mouse and human livers. This implies that the mouse is a more relevant species than the rat in studies of the pharmacology and toxicology of budesonide.     

Synthesis and anti-inflammatory properties of budesonide, a new non-halogenated glucocorticoid with high local activity

As part of a study of the local anti-inflammatory activity of corticosteroid 16 alpha, 17 alpha-acetals it was found that on acetalization of 16 alpha-hydroxyprednisolone with n-butyraldehyde the two possible epimers were formed in the ratio of 1: 1. The reaction product was resolved by column chromatography on Sephadex LH-20. The isolated epimers were studied by NMR and mass spectrometry. The epimeric mixture of this new non-halogenated corticoid, 16 alpha, 17 alpha-(22R,S)-propylmethylenedioxypregna-1,4-diene-11 beta,21-diol-3,20-dione (budesonide), was shown to have a local antiinflammatory potency comparable to that of fluocinolone acetonide in cotton pellet tests in rats. In contrast, its systemic glucocorticoid activity was found to be 4--7 times lower than that of fluocinolone acetonide, however.     

Acute dose-response studies in bronchial asthma with a new corticosteroid, budesonide

1 Budesonide is an epimeric mixture of a new synthetic non-halogenated glucocorticoid (16 alpha, 17 alpha,-(22R,S)-prophylmethylenedioxypregna-1,4-diene-11/3,21-diol-3, 20-dione). 2 Acute dose response studies with three different inhaled doses of budesonide, have been carried out in a group of 12 chronic asthmatic patients. 3 The lowest dose (100 micrograms) of inhaled budesonide produced a more marked effect in relieving airflow obstruction, than a much larger (1600 micrograms) oral dose of the drug. 4 When the area under the curve for peak expiratory flow rate values was calculated, a dose-response relationship could be seen between the different inhaled doses. 5 It appears that budesonide has a predominantly local anti-asthmatic action in the lung.     

氯可托龙新戊酸酯及其有关物质的结构鉴定

目的对氯可托龙新戊酸酯及其原料药中有关物质进行分离及结构鉴定。方法采用制备高效液相色谱法对氯可托龙新戊酸酯中的杂质进行分离,并应用HPLC-ESI-MS、NMR、UV、IR法对氯可托龙新戊酸酯及其有关物质进行结构鉴定。结果氯可托龙新戊酸酯原料药中含有(6R,9R,16R)-9-氯-6β-氟-11β,21-二羟基-16α-甲基-1,4-孕甾二烯-3,20-二酮-21-新戊酸酯[(6R,9R,16R)-9-chloro-6β-fluoro-11β,21-dihydroxy-16α-methylpregna-1,4-diene-3,20-dione-21-pivalate,1]、(9R,16R)-9-氯-4-氟-11β,21-二羟基-16α-甲基-1,4-孕甾二烯-3,20-二酮-21-新戊酸酯[(9R,16R)-9-chloro-4-fluoro-11β,21-dihydroxy-16α-methylpregna-1,4-diene-3,20-dione-21-pivalate,2]和(9R,16R)-9-氯-6α-氟-11β,21-二羟基-16α-甲基-1,4-孕甾二烯-3,20-二酮-11,21-二新戊酸酯[(9R,16R)-9-chloro-6α-fluoro-11β,21-dihydroxy-16α-methylpregna-1,4-diene-3,20-dione-11,21-dipivalate,3]3种杂质。结论从氯可托龙新戊酸酯原料药中分离得到3个杂质,3个化合物均为首次发现。其中杂质1为6-H的差向异构体,杂质2为同分异构体,杂质3为11-OH与新戊酸酯化产物。结合合成过程分析,三者可能均为合成过程中的副产物。     

Ciclesonide: a novel inhaled corticosteroid for asthma

The adoption of inhaled corticosteroids for the treatment of asthma has resulted in significant improvements in asthma symptoms and pulmonary function, and has reduced the incidence of asthma exacerbations, emergency room visits and hospitalizations. Although inhaled corticosteroids are generally safe and well tolerated compared with oral corticosteroids, concerns remain about potential side effects. Clinically significant complications include local effects such as dysphonia and oral candidiasis and potentially serious systemic effects associated with cortisol suppression including growth retardation, glucose intolerance and increased risk for osteoporosis and fractures. These side effects are more likely to occur with long-term use and are dose related. Over the years, attempts have been made to develop corticosteroids with potent local antiinflammatory activity and an improved safety profile. Ciclesonide ([R]-11 beta,16 alpha,17,21-tetrahydroxypregna-1,4-diene-3,20-dione cyclic 16,17-acetal with cyclohexanecarboxaldehyde 21-isobutyrate) was designed to achieve these objectives. Ciclesonide is a parent compound that is converted locally in airways by esterases to produce the active metabolite, desisobutyryl-ciclesonide (des-CIC). The active metabolite, des-CIC, has a 100-fold greater relative glucocorticoid receptor binding affinity than ciclesonide itself (relative glucocorticoid receptor binding affinities are 1200 and 12, respectively; dexamethasone reference is 100). If any ciclesonide enters the circulation, it is highly protein bound (99%) and extensively metabolized by liver oxidases, resulting in very low systemic exposure. Ciclesonide is delivered in solution form via a hydrofluoroalkane metered-dose inhaler (MDI) with a once-daily dosing schedule, which facilitates patient compliance. Clinical studies demonstrate that ciclesonide is as effective as existing "gold standard" inhaled corticosteroids for control of asthma and has a good safety profile.     

A novel class of local antiinflammatory steroids. 2nd communication: pharmacological studies of methyl 11 beta,17 alpha,21- trihydroxy-3,20-dioxo-pregna-1,4-diene-16 alpha-carboxylate and methyl 11 beta,21-dihydroxy-3,20-dioxo-pregna-1,4-diene-16 alpha-carboxylate

Two novel 16-substituted steroidal carboxylate esters derived from prednisolone, methyl 11 beta,17 alpha,21- trihydroxy-3,20-dioxo-pregna-1,4-diene-16 alpha-carboxylate (P16CM) and methyl 11 beta,21-dihydroxy-3,20-dioxo-pregna-1,4-diene-16 alpha- carboxylate (DeoxyP16CM) were evaluated for in vivo antiinflammatory and glucocorticoid activities. Results indicate that incorporation of a methoxycarbonyl group at the 16 position of prednisolone, as in P16CM, resulted in 5.5 times more local activity in the cotton pellet granuloma assay and 14 times more topical activity in the croton oil induced ear edema bioassay as compared with the parent compound prednisolone (P). The 17 alpha-dehydroxy analogue of P16CM (DeoxyP16CM) retained one-half the local activity of P in the cotton pellet granuloma bioassay and topical activity equal to P in the croton oil induced ear edema bioassay. Favorable dissociation of local from systemic effects is seen for these steroidal 16-carboxylate esters since their systemic antiinflammatory activity was significantly less than that of P, and their suppression of plasma corticosterone and ACTH levels was minimal. While P16CM does exhibit some thymolytic activity, DeoxyP16CM is essentially devoid of thymus atrophogenic effects at equiactive doses. Thus, these compounds may represent safer topical therapeutic agents.     

Pharmacological Profile of the Novel Anti-inflammatory Corticosteroid NS-126, a Therapeutic Agent for Allergic Rhinitis

NS-126 (9-fluoro-11β,17,21-trihydroxy-16α-methylpregna-1,4-diene-3,20-dione 21-cyclohexanecarboxylate 17-cyclopropanecarboxylate) is a novel, highly lipophilic anti-inflammatory corticosteroid. We compared NS-126 and the widely used intranasal corticosteroid fluticasone propionate (FP) in a guinea-pig model of allergic rhinitis and a rat model of airway eosinophilia. In the allergic rhinitis model, NS-126 and FP reduced sneezing and nasal obstruction to similar extents. In the airway eosinophilia model, both compounds inhibited the infiltration of eosinophils into the bronchoalveolar lavage fluid, but the effect of NS-126 was longer-lasting than that of FP. In vitro, NS-126 showed lower affinity than FP for the glucocorticoid receptor and was a weaker inhibitor of Th₂ cytokine and chemokine production and mast-cell secretory responses. We also investigated DX-17-CPC, a metabolite of NS-126 generated in nasal tissue by carboxylesterasecatalyzed hydrolysis at the 17-position. DX-17-CPC showed greater affinity than NS-126 for the glucocorticoid receptor and was a stronger inhibitor of Th₂ cytokine and chemokine production and mast-cell secretory responses. The long duration of the anti-allergic effects of NS-126 may be explained by its high lipophilicity, while the strength of its anti-allergic effects may be explained by the generation of the active metabolite DX-17-CPC. NS-126 is a long-acting intranasal corticosteroid and a promising therapeutic agent for allergic rhinitis.     

An experimental and computational study on the epimeric contribution to the infrared spectrum of budesonide

Budesonide is a mixture of 22R and 22S epimers. The epimeric content of budesonide was reported in both British and European pharmacopoeias to be within the range of 60–49/40–51 for R and S epimers, respectively. In this work, contribution of the two epimers to the overall infrared spectrum of budesonide has been investigated by quantum chemical calculations. Copyright © 2010 John Wiley & Sons, Ltd.     

Mometasone furoate degradation and metabolism in human biological fluids and tissues

The in vitro metabolic and non-metabolic degradation kinetics of mometasone furoate (MF) was investigated in selected human biological fluids and subcellular fractions of tissues. Qualitative and quantitative differences in transformation profiles of MF were observed among human biological media. Degradation was the major event in plasma and urine with four new degradation products identified; A: 21-chloro-17alpha-hydroxy-16alpha-methyl-9beta,11beta-oxidopregna-1,4-diene-3,20-dione 17-(2-furoate), B: 9alpha,21beta-dichloro-11beta,21alpha-dihydroxy-16alpha-methylpregna-1,4,17,20-tetraen-3-one 21-(2-furoate), C: 21beta-chloro-21alpha-hydroxy-16alpha-methyl-9beta,11beta-oxidopregna-1,4,17,20-tetraen-3-one 21-(2-furoate), and D: 21-chloro-17alpha-hydroxy-16alpha-methyl-9beta,11beta-oxidopregna-1,4-diene-3,20-dione. A, B and C were predominant and D was minor in plasma while A and C were predominant in urine. Hydrolysis of the 17-ester bond of MF was not a major event in plasma. The turnover of MF in plasma was faster than that in phosphate buffers of pH 7.4.Metabolism of MF occurred primarily and rapidly in liver, appreciably in intestine, but negligibly in in vitro lung tissue. While 6beta-hydroxylation was a major metabolic pathway for MF in microsomes of both human liver and intestine, other parallel and subsequent metabolism pathways could also be involved. If these degradation and metabolic products are also formed and active in humans in vivo, both MF and its 'active' products need to be taken into account when determining the systemic bioavailability of MF and in establishing concentration-effect relationships with this drug.     

The blood-brain barrier permeability of 20(S) and 20(R)-protopanaxatriol epimers and dammar-20(22)E,24-diene-3β,6α,12β-triol in MDCK-pHaMDR cell monolayer model

The blood-brain barrier permeability of 20(S) and 20(R)-protopanaxatriol epimers and dammar-20(22)E,24-diene-3β,6α,12β-triol were investigated using the MDCK-pHaMDR cell monolayer model. The bidirectional permeability tests were carried out, and the apparent permeability coefficients (P_app) were calculated. The two protopanaxatriol epimers showed good permeability with P_app values of ~10^–5 cm/s, whereas dammar-20(22)E,24-diene-3β,6α,12β-triol showed poor permeability with P_app of <1×10^–7 cm/s. The three compounds showed differences in intracellular accumulations due to their different structures. Inhibition of P-gp with verapamil showed that the transport mechanisms in MDCK-pHaMDR cell monolayer for compounds 1and 2 epimers were not only simple passive diffusion but also involving an efflux way mediated by P-gp. These findings provided new basis for the further study of compounds 1 and 2 acting on the brain.     

High-performance liquid chromatographic separation and identification of epimeric 17-ketone impurities in commercial sample of dexamethasone sodium phosphate.

A commercial sample of dexamethasone sodium phosphate solution for injection was found to contain 56% of the label concentration and to be extensively contaminated (approximately 50%) with a white insoluble solid, which was identified as a mixture of the 16 alpha- and 16 beta-methyl epimers of 9-fluoro-11 beta-hydroxy-16-methylandrosta-1,4-diene-3,17-dione. High-performance liquid chromatography (HPLC) was used to separate, identify, and quantitate these epimers and to determine their presence in commercial samples. One epimer was identified by HPLC comparison with a synthesized specimen of 9-fluoro-11 beta-hydroxy-16 alpha-methylan-drosta-1,4-diene-3,17-dione. The second peak was identified as the 16 beta-epimer by epimerization of the synthesized alpha-component with alkali to obtain a product whose chromatogram matched that of the impurity. These conclusions are supported by data obtained by IR and UV spectrophotometry, TLC, and the blue tetrazolium test.     

Epimerization of erythromycin derivatives

Dirithromycin (3) isomerizes upon dissolution in different solvents. From X-ray analysis of V-T 108, an analogue of dirithromycin, and comparative 1H and 13C NMR, and MS data, the isomer of dirithromycin was confirmed to be the C-16-(S)-epimer. The ratio of the two epimers at equilibrium conditions was approximately 8:2 (R/S) in methanol at room temperature.     

安宫黄体酮母液中两个新化合物的分离与结构鉴定

目的研究药物安宫黄体酮中所含的杂质。方法应用柱色谱方法进行分离和纯化，NMR和MS等波谱方法确定结构。结果从安宫黄体酮母液中分离得到2个化合物。结论化合物1和2为新差向异构体，其结构分别鉴定为：17α-氧乙酰基-2β，6α-二甲基孕甾-4-烯-3，20-二酮；17α-氧乙酰基-2α，6α-二甲基孕甾-4-烯-3，20-二酮。     

Bromine- and iodine-substituted 16alpha,17alpha-dioxolane progestins for breast tumor imaging and radiotherapy: synthesis and receptor binding affinity

Progesterone receptors (PRs) are present in many breast tumors, and their levels are increased by certain endocrine therapies. We describe the synthesis and PR binding affinities of a series of bromine- and iodine-substituted 16alpha,17alpha-dioxolane progestins, some of which, when appropriately radiolabeled, are potential agents for diagnostic imaging of PR-positive breast tumors using positron emission tomography (PET) and for radiotherapy. These compounds were synthesized from halogenated furanyl, phenyl, and thiophenyl aldehydes and a progestin 16alpha,17alpha,21-triol (5) in the presence of HClO4 or Sc(OTf)3 in high yields under optimized conditions. A new reagent, perfluoro-1-butanesulfonyl fluoride (PBSF), was used to convert the C-21 OH to F in high yields. The relative binding affinities (RBAs) of the most promising compounds for the PR (RBA of R5020 = 100) were 16alpha,17alpha-[(R)-1'-alpha-(5-bromofurylmethylidene)dioxyl]-21-hydroxy-19-norpregn-4-ene-3,20-dione (endo-6; RBA = 65 and moderate lipophilicity), 21-fluoro-16alpha,17alpha-[(R)-1'-alpha-(5-iodofurylmethylidene)dioxyl]-19-norpregn-4-ene-3,20-dione (endo-14; RBA = 40) and 21-fluoro-16alpha,17alpha-[(S)-1'-beta-(4-iodophenylmethylidene)dioxyl]-19-norpregn-4-ene-3,20-dione (exo-16; RBA = 34).     

Preliminary clinical evaluation of a new topical corticosteroid, halopredone acetate, as compared to fluocinonide.

17,21-Bis(acetyloxy)-2-bromo-6beta,9-difluoro-11beta-hydroxypregna-1,4-diene-3,20-dione (halopredone acetate; Topicon), a new corticosteroid for topical use, was compared with fluocinonide in a double blind sequential study. The tests were made on a total of 16 patients affected with psoriasis and exudative dermatitis. In each patient, the symmetrically distributed skin lesions were separately treated with either halopredone acetate or the reference compound. The two active substances were in the same concentration (0.05%) in the same carrier (cream), and both reduced the subjective and objective symptoms of these skin conditions. No statistically significant differences were observed between the two medicated areas. Haloperidone acetate, the excipients of the cream and the reference compound were all excellently tolerated.     

Sulfation of budesonide by human cytosolic sulfotransferase, dehydroepiandrosterone-sulfotransferase (DHEA-ST).

Budesonide, a synthetic glucocorticosteroid, is used in the treatment of asthma and allergic reactions, rhinitis, and inflammatory bowel disease. It is distributed as a mixture of two epimers, 22R and 22S, and has a high ratio of topical to systemic activity due to extensive first-pass metabolism to metabolites with minimal activity. Previous studies have shown that the epimers are metabolized by the cytochrome P450 monooxygenase system. Metabolism and inactivation of the epimers by the phase II enzymes has not been well characterized. This study describes the conjugation of budesonide by human cytosolic sulfotransferases (SULTs). Seven human SULTs were analyzed to determine which were capable of catalyzing the sulfation of the epimers of budesonide. Only dehydroepiandrosterone-sulfotransferase (DHEA-ST, SULT2A1) was capable of forming a sulfated budesonide product. The epimeric forms of budesonide display different kinetic activities with the 22R epimer having a 3.5-fold greater rate of sulfation activity than the 22S epimer. The structure of budesonide shows two hydroxyl sites that are potential sites for sulfate conjugation, but analysis by mass spectrometry indicates the formation of only a monosulfated budesonide product. A modeling approach was used to define the site of sulfation as that of the 21-hydroxyl group. Although sulfation of budesonide by DHEA-ST may not be an important factor in its use as an antiasthmatic, intestinal and hepatic sulfation will be important for its proposed systemic use as an anti-inflammatory agent.     

Glucocorticoid activity and structure activity relationships in a series of some novel 17 alpha-ether-substituted steroids: influence of 17 alpha-substituents.

A series of non-fluorinated glucocorticoids, cortienic acid analogs with a 17 beta-chloromethyl ester and various 17 alpha-ether functions, were tested for their affinity to the rat-lung type-II glucocorticoid receptor. The relative binding affinity of a set of 9 compounds was determined in a competitive experiment with [1,2,4-3H]triamcinolone acetonide. The highest binding affinities were observed with the 17 alpha-propoxy and butoxy analogs which were 1.3 times more active than the standard dexamethasone. Quantitative analysis of the results suggested that steric factors and lipophilicity of the side-chain were the major parameters affecting receptor affinity. Representative members of the series were compared to betamethasone 17 alpha-valerate in a vasonstriction test. The results paralleled those of the receptor binding experiment, indicating that the new steroids have good skin-permeation properties and good glucocorticoid activity.     

Fluorocarbocyclic nucleosides: synthesis and antiviral activity of 2'- and 6'-fluorocarbocyclic 2'-deoxy guanosines.

A series of four isomeric 2'- and 6'-fluorocarbocyclic guanosine analogues have been prepared and evaluated as potential anti-herpes agents. The racemic 2' beta-fluoro isomer 2-amino-1,9-dihydro- 9-[(1 alpha, 2 alpha, 3 beta, 4 alpha)-2-fluoro-3-hydroxy-4- (hydroxymethyl)cyclopentyl]-6H-purin-6-one (11a, C-AFG) and its 2' alpha-fluoro epimer 11b plus the chiral 6' beta-fluoro isomer 2-amino-1,9-dihydro-9-[[1S-(1 alpha, 2 alpha, 3 alpha, 4 beta)]- 2-fluoro-4-hydroxy-3-(hydroxymethyl)cyclopentyl]-6H-purine-6-one (11c) and its 6' alpha-fluoro epimer 11d were prepared from their respective fluoro amino diol hydrochlorides (6a,d). For comparison, the furanosyl compound 9-(2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl)guanine (17, AFG) was prepared by coupling 2-amino-6-chloropurine with 2-deoxy-2-fluoro-3,5-di-O-benzoyl-alpha- D-arabinofuranosyl bromide followed by base hydrolysis. The 6' alpha-fluoro derivative 11d exhibited comparable activity to that of acyclovir (ACV) against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in vitro but was greater than 30-fold more active than ACV against HSV-1 and HSV-2 in vivo in the mouse systemic model. The 2' beta-fluoro derivative (11a, C-AFG) was extremely potent in vitro against HSV-1 and HSV-2 (ID50 0.006 and 0.05 micrograms/mL) and in vivo it was greater than 2 orders of magnitude more potent than ACV against HSV-1 and 70-fold more potent against HSV-2. The 2' alpha-fluoro 11b and 6' beta-fluoro 11c isomers were much less active.