In vitro biotransformation of glucocorticoids in liver and skin homogenate fraction from man, rat and hairless mouse

Budenoside aqueous nasal spray: an updated reappraisal in rhinitis management

Allergic rhinitis (AR) and nonallergic rhinitis are prevalent diseases. In western countries, type 2 inflammation usually characterizes these medical conditions and mainly sustains nasal obstruction. Budesonide aqueous nasal spray (BANS) is an intranasal corticosteroid (INCS) that has been available since the early 1980s. BANS is indicated for treating allergic rhinitis, nonallergic rhinitis, and nasal polyps (both as treatment and prevention after surgery). Consolidated evidence confirms its efficacy in treating seasonal and perennial AR, and nonallergic rhinitis. In addition, BANS is safe with negligible local and systemic side effects. Recent guidelines for patients with AR recommend using INCS as the first line in many situations. In particular, patients may assess the perception of symptoms' severity using the Visual Analog Scale. A score ≥5/10 means uncontrolled symptoms and requires adequate treatment. BANS could appropriately be used in patients with uncontrolled symptoms and/or moderate/severe nasal obstruction. In conclusion, BANS represents a valuable option in managing patients with type 2 inflammation of the nose.

Validation of a HPLC-UV method for the quantification of budesonide in skin layers

A simple and sensitive HPLC method for the quantification of budesonide in skin layers was developed and validated. Budesonide was extracted from stratum corneum, epidermis and dermis by means of a mixture of acetonitrile:water (recovery > 90%). Budesonide quantification was performed with a RP-C18 column using methanol and water mixture (69:31, v/v) as mobile phase, pumped at 0.8 ml/min. The absorbance was monitored at 254 nm. The method resulted to be selective, linear in the range 0.05-5 or 10 μg/ml, precise and accurate. LLOQ resulted to be 0.05 μg/ml. The developed method appeared to be appropriate for the quantification of budesonide in skin layers at the end of in vitro permeation experiments since the recovery of the applied dose was 97 ± 1%, in line with requirement of the OECD guideline for the testing of the chemicals (Skin absorption: in vitro method).

Systematic review: second-generation vs. conventional corticosteroids for induction of remission in ulcerative colitis

BACKGROUND

Oral corticosteroids are the mainstay treatment for induction of ulcerative colitis remission in patients failing or intolerant to aminosalicylate therapy, but the poor tolerability profile of these drugs limits their usefulness. Second-generation, gut-selective corticosteroids may offer a safe alternative to systemic agents.

AIM

To review the efficacy and safety of systemic and second-generation oral corticosteroids for the induction of remission in ulcerative colitis.

METHODS

The PubMed database was searched for randomised, controlled, and open-label trials of orally administered corticosteroids published between January 1950 and September 2015. Additional trials were identified from review of citation lists. Trials that compared oral corticosteroids with non-oral agents or in combination with agents other than aminosalicylates were excluded.

RESULTS

Of the 240 studies identified, 21 were eligible for inclusion. Few trials directly compared oral systemic and second-generation corticosteroids (n = 4). Some second-generation corticosteroids had questionable efficacy vs. placebo or mesalazine (mesalamine), but beclomethasone dipropionate and budesonide MMX demonstrated a comparative benefit. Only beclomethasone dipropionate was similar to conventional corticosteroids for induction of remission and other clinical endpoints. Direct comparative trials for budesonide MMX were unavailable. Second-generation corticosteroids had an overall favourable safety profile, with minimal adverse effects on cardiovascular and metabolic parameters and a low incidence of adverse events.

CONCLUSIONS

Beclomethasone dipropionate and budesonide MMX provide greater induction of remission in ulcerative colitis than placebo or mesalazine but additional active-comparator trials are needed to firmly establish the efficacy profile vs. systemic corticosteroids. Second-generation corticosteroids have a more favourable safety and tolerability profile than systemic corticosteroids.

Budesonide Foam Has a Favorable Safety Profile for Inducing Remission in Mild-to-Moderate Ulcerative Proctitis or Proctosigmoiditis

BACKGROUND

Budesonide foam, a rectally administered, second-generation corticosteroid with extensive hepatic first-pass metabolism, is efficacious for the treatment of mild-to-moderate ulcerative proctitis and ulcerative proctosigmoiditis.

AIM

The aim of this study was to comprehensively assess the safety and pharmacokinetic profile of budesonide foam.

METHODS

Data from five phase III studies were pooled to further evaluate safety, including an open-label study (once-daily treatment for 8 weeks), an active-comparator study (once-daily treatment for 4 weeks), and two placebo-controlled studies and an open-label extension study (twice-daily treatment for 2 weeks, then once daily for 4 weeks). Data from the placebo-controlled studies and two phase I studies (i.e., patients with mild-to-moderate ulcerative colitis and healthy volunteers) were pooled to evaluate the pharmacokinetics of budesonide foam.

RESULTS

A similar percentage of patients reported adverse events in the budesonide foam and placebo groups, with the majority of adverse events being mild or moderate in intensity (93.3 vs 96.0%, respectively). Adverse events occurred in 41.4 and 36.3% of patients receiving budesonide foam and placebo, respectively. Mean morning cortisol concentrations remained within the normal range for up to 8 weeks of treatment; there were no clinically relevant effects of budesonide foam on the hypothalamic-pituitary-adrenal axis. Population pharmacokinetic analysis demonstrated low systemic exposure after budesonide foam administration.

CONCLUSIONS

This integrated analysis demonstrated that budesonide foam for the induction of remission of distal ulcerative colitis is safe overall, with no clinically relevant effects on the hypothalamic-pituitary-adrenal axis.

Kinetics of metabolism and degradation of mometasone furoate in rat biological fluids and tissues

Mometasone furoate (MF) is a potent glucocorticoid developed for the treatment of glucocorticoid-responsive inflammatory disorders. The in-vitro and ex-vivo kinetics of the degradation and metabolism of MF were studied in selected biological fluids of rat and subcellular fractions of different rat tissues. In-vitro, MF was found to degrade slowly into four products in serum and urine, and metabolized rapidly and extensively in rat liver, minimally in extrahepatic tissues, including intestine, stomach, lung and kidney. Further investigation found that the microsomal fraction was the major intracellular site of MF 6 beta-hydroxylation in rat liver. Using chemical inhibitors, CYP3A was found to be the major enzyme involved in the in-vitro MF 6 beta-hydroxylation in rat liver microsomes. Enzyme kinetic studies in rat liver microsomes showed that the overall metabolic process of MF followed biphasic Michaelis-Menten kinetics, while 6 beta-hydroxylation obeyed monophasic Michaelis-Menten kinetics. The kinetic parameters derived from the kinetic models along with the enzyme inhibition studies suggest that MF is mainly metabolized via 6 beta-hydroxylation mediated by CYP3A primarily, and also biotransformed via other pathway(s) catalysed by other enzymes in rat liver in-vitro.

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.

Biotransformation in vitro of the 22R and 22S epimers of budesonide by human liver, bronchus, colonic mucosa and skin

The pharmacological effects of glucocorticoids are greatly influenced by their pharmacokinetic properties. In the present report, the in vitro biotransformation of the 22R and 22S epimers of the topical steroid budesonide was studied in the S-9 fraction of human liver, bronchus, skin and colonic mucosa. The disappearance of unchanged epimers of budesonide was measured during 90 min of incubation by high performance liquid chromatography. The rate of disappearance was high in human liver while little biotransformation occurred in bronchial tissue and colonic mucosa, and none was detected in the skin. A marked decay of the initial concentration of unchanged budesonide epimers was noticed after 2 h incubation in cultured human hepatocytes, while only a small decrease was observed after 24 h incubation in cultured human airway smooth muscle cells and BEAS-2B cells. The 22R epimer of budesonide suffered greater in vitro biotransformation than the 22S epimer in human hepatic, bronchial and colonic tissues. These findings extend those of other studies, and confirm that the high therapeutic ratio of budesonide is due to negligible local biotransformation combined with high level of liver metabolism for locally absorbed budesonide.

A stability-indicating HPLC assay method for budesonide

The official (European) pharmacopeial assay for budesonide was found to be non-specific and non-stability-indicating when used to qualify several batches of pharmaceutical grade drug substance from different sources. In contrast, the most widely cited HPLC method in the literature was found to be specific and stability-indicating with respect to drug substance stored in the dry state. However, that method failed the pharmacopeia's assay system suitability requirements because of peak tailing. Moreover, it was unable to detect or resolve two major degradation products which resulted from drug storage in non-aqueous solution. A new stability-indicating HPLC method described here overcomes these problems. This method used a Hypersil C18 column with a mobile phase consisting of ethanol-acetonitrile phosphate buffer (pH 3.4; 25.6 mM) (2:30:68, v/v/v), a flow rate of 1.5 ml/min and UV detection at 240 nm. The purity of budesonide EP and its impurity profile (related substances) were tested using the new assay method, and the results compared to those from the two other methods described above. Solid-state and solution stressed stability samples were used to evaluate all methods. Using the novel method, the epimers of budesonide. their related impurities and degradation products were separated successfully. Validation studies demonstrated that the novel method possessed a linear UV response, good system precision and accuracy, high sensitivity and specificity for budesonide. The novel method will be used for future studies of budesonide's degradation kinetics.

Determination of celecoxib in human plasma by normal-phase high-performance liquid chromatography with column switching and ultraviolet absorbance detection

A method is described for the determination of celecoxib in human plasma. Samples were extracted using 3M Empore membrane extraction cartridges and separated under normal-phase HPLC conditions using a Nucleosil-NO2 (150x4.6 mm, 5 microm) column. Detection was accomplished using UV absorbance at 260 nm. The HPLC method included a column switching procedure, in which late eluting compounds were diverted to waste, to reduce run-time to 12 min. The assay was linear in the concentration range of 25-2000 ng/ml when 1-ml aliquots of plasma were extracted. Recoveries of celecoxib were greater than 91% over the calibration curve range. Intraday precision and accuracy for this assay were 5.7% C.V. or better and within 2.3% of nominal, respectively. The assay was used to analyze samples collected during human clinical studies.

Effects of short-term inhaled budesonide and beclomethasone dipropionate on serum osteocalcin in premenopausal women

Serum osteocalcin, a marker of bone osteoblast function, has been shown to be sensitive to even low doses of oral glucocorticoids. The effect of 1 wk of inhaled glucocorticoid therapy with budesonide (200 micrograms/puff), beclomethasone dipropionate (250 micrograms/puff), and placebo at two puffs b.i.d. and four puffs b.i.d. on 0900 serum osteocalcin were compared in a double-blind randomized fashion. A two-way repeated-measures analysis of variance showed no main effect of drug or dosage but a significant drug-dose interaction (p = 0.023). Post hoc investigation of this interaction demonstrated that the serum osteocalcin level while taking four puffs b.i.d. (2,000 micrograms) of beclomethasone dipropionate was significantly lower than that of placebo or budesonide at four puffs b.i.d. (1,600 micrograms). These results suggest that at lower doses no acute measurable effect of inhaled glucocorticoids on serum osteocalcin can be appreciated but that at higher doses inhaled beclomethasone dipropionate has a depressant effect on bone osteoblast function.

Comparison of two glucocorticoid preparations (deflazacort and prednisone) in the treatment of immune-mediated diseases

Different glucocorticoid preparations modify the immune reaction in different ways. In this paper, the therapeutic efficacy of two glucocorticoids, deflazacort (DFZ) and prednisone (PDN), are discussed in relation to a group of 30 patients with systemic lupus erythematosus (n = 12) or rheumatoid arthritis (n = 18). The disease sub-groups were divided into two arms, one of which was treated with DFZ and one with PDN in a double-blind protocol. The results of this study indicate that DFZ and PDN induced a clinical remission within 1 month which was maintained until the 6th month. Nevertheless, certain immunological modifications, including a significant reduction of the circulating T lymphocyte level and of the CD4/CD8 ratio, which was between 1 and 1,5 during the DFC treatment and between 1 and 2 during the PDN treatment, are more pronounced and more stable with DFZ than with PDN. Moreover, DFZ has a smaller effect on calcium and glucose metabolism than PDN since the serum glucose and calcium level of patients treated with PDN increased respectively from 90 up to 130 mg/dl and from 9,5 to 11,5 mg/dl whereas those of patients treated with DFC remained within the normal range. These findings indicate that DFZ may have advantages over PDN in the treatment of immune-mediated diseases.

Rapid metabolic inactivation of tipredane, a structurally novel topical steroid

[3H]Tipredane ([3H]TP), [3H]triamcinolone acetonide ([ 3H]TAAC), [3H]hydrocortisone ([3H]HC), and [3H]betamethasone-17 alpha-valerate ([3H]BMV), each at a concentration of 1 microM, were separately incubated with the 10,000 g supernatant fraction of the liver and skin homogenates of humans, rats and mice (BMV was studied only in human liver). Sequential samples were taken for up to 1 h during each incubation. The radioactivity in each sample was extracted with methanol, and the methanolic extracts were analyzed by high performance liquid chromatography. Among the four compounds studied, [3H]TP was most rapidly biotransformed by the liver preparations of the three species. The rates of in vitro biotransformation of TP were 2.5-30 times faster than those of TAAC, HC and BMV. In the human liver preparation, the rates of biotransformation were in the order of: TP greater than TAAC greater than HC = BMV. In the mouse and rat liver preparations, the orders were: TP greater than TAAC greater than HC and TP greater than HC greater than TAAC, respectively. In the skin preparations, little, if any, biotransformation of [3H]TP and [3H]TAAC was observed in any of the species studied; however, [3H]HC underwent a slow, steady biotransformation in the skin preparations of humans and rats but not of mice. [3H]TP was biotransformed by the liver preparations of all three species to numerous metabolites, thirteen of which have been identified. The biotransformation reactions included: (1) sulfoxidation; (2) elimination of either one or both alkylthio groups; and (3) hydroxylation of the steroid nucleus. Some metabolites were synthesized and tested for glucocorticoid receptor binding and anti-inflammatory activities; all were found to be much less potent than TP. The observed separation of local anti-inflammatory activity from systemic side effects of TP is most probably due to its rapid metabolic inactivation; the liver, rather than the skin, is mainly responsible for the metabolic inactivation of TP.

The use of on-line liquid chromatography/mass spectrometry and stable isotope techniques for the identification of budesonide metabolites

A moving belt interface was used to identify budesonide metabolites, obtained from rat and mouse liver incubations, by liquid chromatography/mass spectrometry (LC/MS). The metabolites were separated on a small-bore C18 column with an ethanol/water gradient as mobile phase at a flow rate of 0.2 ml min-1. A spray device was used for deposition of the aqueous solvent on to the belt. Chemical ionization mass spectra were obtained with methane as the reagent gas. Deuterium-labelled budesonide, which was used to facilitate metabolite identification by the isotope cluster technique, was found to be slightly separated from the unlabelled analogue on the LC column. Incubations were also performed under 18O2 to elucidate the mechanism of a new metabolic pathway (16 alpha, 17 alpha-acetal splitting) and to confirm the oxidative nature of reactions leading to hydroxylated metabolites. The moving belt LC/MS technique afforded higher sensitivity, and gave more abundant MH+ ions of the compounds studied, than previously found by direct probe mass spectrometry. Phthalate ester background, partly from the polymide belt, complicated the identification of minor metabolites.

Pharmacokinetics of budesonide in children with asthma

The pharmacokinetics of the glucocorticoid budesonide was studied in 6 children with asthma after i.v. injection of 0.5 mg and oral inhalation of 1 mg as an aerosol. Budesonide is a 1:1 mixture of the epimers 22 S and 22 R, which were assayed separately by HPLC combined with RIA. All pharmacokinetic parameters of the epimers differed except the half-life of about 1.5 h. It was significantly shorter than that reported in adults. Plasma clearance averaged 103 l X h-1 for epimer 22 R and 74 l X h-1 for epimer 22 S; calculated per kg body weight these values were about 50% higher than in adults. The difference was about 40% when calculated per m2 of body surface area. Since budesonide is a high-clearance drug, the data indicate higher liver blood flow X kg-1 body weight and m2 of body surface area in children. The systemic availability of the aerosol was approximately 30% of nominal dose, i.e. the same as in adults. The high clearance and short half-life of budesonide in children are advantageous in reducing the risk of possible systemic side-effects of prophylactic treatment of asthma in childhood.

Effect of structural alterations on the biotransformation rate of glucocorticosteroids in rat and human liver

The effect of structural alterations on the biotransformation rate of glucocorticosteroids (GCS) by rat- and human-liver 9000 g supernatant fraction was studied. Insertion of a 16 alpha-hydroxy group in the prednisolone molecule (16 alpha-hydroxyprednisolone) was found to decrease the rate of biotransformation. Substitution of the 16 alpha,17 alpha-hydroxy groups with a symmetric acetal (in, for example, desonide) or especially a non-symmetric acetal (in, for example, budesonide), enhanced the biotransformation rate several-fold, particularly in human liver. Differences in the rates of metabolism in rat and human liver were observed. Hydrogenation of the 1,2-double bond in prednisolone and budesonide (hydrocortisone and 1,2-dihydrobudesonide) enhanced the biotransformation rate nine-fold in rat liver but only two-fold in human liver. Fluorination of the steroid nucleus in 6 alpha- and 9 alpha-positions enhanced the biotransformation rate several-fold in human liver, but in rat liver fluorination marginally decreased the rate of biotransformation. These in vitro results correlate well with available data on the first-pass liver metabolism of the studied GCS. This indicates that in vitro data can be useful in predicting oral bioavailability of GCS.

Tissue distribution and fate of budesonide in the mouse

The tissue distribution and pharmacokinetics of 3H-budesonide were studied in the mouse after intravenous administration. The drug was rapidly (t1/2 alpha = 0.062 hrs) and extensively distributed into tissues and organs (V beta = 20.3 l/kg and Vss = 9.4 l/kg). The short elimination half-life (t1/2 beta = 1.55 hrs) and high blood clearance (Cl = 9.04 l/hr/kg) demonstrated a rapid elimination of budesonide from the body. Whole-body autoradiography showed very high amounts of radioactivity in the excretory organs liver and kidney. Also in the lung and lymphatic tissues high amounts of radioactivity were noted. The adrenal cortex but not the medulla was heavily labelled. Radioactivity passed the blood-placenta barrier and to some extent the blood-brain barrier. The identity of the radioactivity in some organs was analysed by liquid chromatography. At all times after dosing (up to 4 hours), the dominating part of the lung, spleen and brain radioactivity was attributable to unchanged budesonide. After 60 min., the dominating part of the kidney radioactivity was identified as polar metabolites of budesonide. The liver radioactivity was at all observation times found to consist mainly of polar metabolites, reflecting the efficient liver biotransformation of budesonide.

Use of budesonide in the treatment of pulmonary sarcoidosis

Twenty patients with active sarcoidosis (increased serum ACE activity) and progressive pulmonary disease (stages 2-3) were treated with inhaled budesonide instead of with oral glucocorticosteroids in an open clinical study. Results after an 18-month treatment are reported. A general improvement in chest roentgenograms and FVC was noted. Serum ACE activity was normalized. The results indicate that pulmonary manifestations of sarcoidosis can be treated with the inhaled steroid, budesonide. In this way the risk of systemic side effects is considerably reduced. The final place of inhaled budesonide in the treatment of sarcoidosis must be determined via placebo-controlled and comparative, double-blinded clinical studies in larger series of patients.

Nasal bioavailability and systemic effects of the glucocorticoid budesonide in man

Budesonide, a topically potent glucocorticoid, was administered to 4 healthy volunteers by i.v. infusion and by nasal instillation of 100 micrograms tritium-labelled drug. Plasma was analyzed by liquid chromatography plus scintillation counting of collected fractions. After i.v. administration the plasma clearance was 0.921/min and the apparent volume of distribution was 2.81/kg. After nasal administration, the time to reach the peak plasma level was approximately 30 min, and the systemic availability was 102%. Budesonide had marginal effects on plasma cortisol and white blood cell counts either after i.v. or nasal administration. Thus, nasally instilled budesonide in solution is rapidly and completely absorbed from the nasal mucosa. The systemic effects after this clinically recommended nasal dose were negligible.

Budesonide. A preliminary review of its pharmacodynamic properties and therapeutic efficacy in asthma and rhinitis

Budesonide is a non-halogenated glucocorticosteroid which has been shown to possess a high ratio of topical to systemic activity compared with a number of reference corticosteroids such as beclomethasone dipropionate, flunisolide, and triamcinolone acetonide. It appears to undergo extensive first-pass metabolism to metabolites of minimal activity which accounts for the low level of systemic activity. The majority of therapeutic trials in asthma have been of short term duration and have demonstrated that conventional doses of inhaled budesonide (200 to 800 micrograms/day) and beclomethasone dipropionate (400 to 800 micrograms/day) are of similar efficacy in both adults and children with moderate to severe asthma. Other studies have compared high doses of inhaled budesonide (400 to 3200 micrograms/day in 4 divided doses) with both alternate day (7.5 to 60 mg) and daily (7.5 to 40 mg) oral prednisone in patients with severe or unstable asthma. In the small number of such trials to date, inhaled budesonide was superior to prednisone with respect to the level of asthma control and the lesser influence on adrenal function. Long term open studies have similarly shown that inhaled budesonide can be gradually substituted for oral prednisone in steroid-dependent patients, often with a concomitant improvement in pulmonary function and asthma control. Intranasal budesonide (200 to 400 micrograms/day) relieves nasal symptoms in patients with seasonal allergic, perennial allergic and vasomotor rhinitis. In comparative studies in patients with seasonal rhinitis it has been shown to be of similar efficacy as intranasal flunisolide and intranasal beclomethasone dipropionate and superior to intranasal sodium cromoglycate (cromolyn sodium) and the antihistamine dexchlorpheniramine. Following inhalation, the most commonly reported side effects have been candidiasis, dysphonia and sore throat, while after intranasal administration the most frequent adverse reactions have been nasal stinging, throat irritation, dry nose and slight nasal bleeding. At usual dosages, both formulations of budesonide appear to have little or no effect on adrenal function. Thus, at this stage in its development budesonide has been shown to offer an effective alternative to oral or other inhaled corticosteroids in the management of asthma and rhinitis. However, its relative efficacy and tolerability during long term use, compared with beclomethasone dipropionate, remains to be clarified.

Biotransformation rate (in vitro) and systemic potency (in vivo) of the topical glucocorticoid budesonide in male and female rats

Budesonide is a glucocorticoid of clinical interest for the topical treatment of skin and respiratory diseases. The in vitro liver biotransformation rate and in vivo systemic potency (thymus involution) of budesonide were studied in male and female rats. The biotransformation rate of [3H]-budesonide was about 4 times slower in the female than in the male rat liver 9000 g supernatant (t 1/2; 230 and 57 min, respectively). The systemic potency of budesonide after peroral or subcutaneous administration was higher (by factors of 6 and 2, respectively) in the female than in the male rat. These results suggest that the liver biotransformation rate of budesonide is of great importance in reducing its systemic action in the male rat.

Effect of glucocorticoids on glycosaminoglycan metabolism in cultured human skin fibroblasts

Human skin fibroblasts were exposed to 3 anti-inflammatory steroids in order to study their effects on the glycosaminoglycan metabolism. The potent glucocorticoids, fluocinolone acetonide and budesonide, even at low concentrations strongly reduced the accumulation of hyaluronic acid and sulfated glycosaminoglycans in the medium, at the cell surface, and in the cells. Hydrocortisone had considerably less effect. The 3 compartments were not influenced to the same extent and the least inhibition was noted in the cell surface pool. Dermatan sulfate was decreased to the same relative extent in all 3 compartments, while hyaluronic acid and heparan sulfate were specifically retained at the cell surface, explaining why this compartment was less affected than the others. Dermatan sulfate was studied in more detail regarding effects on its copolymeric structure. Glucocorticoid treatment changed the uronosyl composition of the polysaccharides so that a relative decrease of glucuronic acid residues and a relative increase of iduronic acid residues were noted. This change was most evident in dermatan sulfate of the medium and of the cell surface. Thus, glucocorticoid treatment not only reduces the quantity of various glycosaminoglycans but also changes the distribution, the relative proportion, and the structure of connective tissue proteoglycans. These effects probably contribute to the development of skin atrophy, which often is observed after long-term treatment with potent glucocorticoids.

Topical and systemic glucocorticoid potencies of budesonide and beclomethasone dipropionate in man

Topical anti-inflammatory (cutaneous "vasoconstriction") and systemic glucocorticoid (depression of plasma cortisol and changes in differential WBC count) potencies of the two glucocorticoids budesonide and beclomethasone dipropionate (BDP) were compared in human volunteers. After topical application, budesonide was 2-3 times more potent than BDP in inducing "vasoconstriction". After oral administration, on the other hand, budesonide was 2-4 times less potent than BDP in depressing plasma cortisol and changing the total or differential WBC. After inhalation, too, significant differences in favour of budesonide were noted, but the divergence between the drugs was less pronounced. The improved relationship between the topical and systemic glucocorticoid effects of budesonide makes it a promising alternative for aerosol treatment in asthma.

Influence of 16 alpha, 17 alpha-acetal substitution and steroid nucleus fluorination on the topical to systemic activity ratio of glucocorticoids

The use of topical glucocorticosteroid therapy on large skin areas or in the lung is sometimes restricted by the occurrence of unwanted, general corticoid actions owing to a profound systemic absorption. To decrease this risk potent glucocorticoids with an enhanced ratio between their topical and their systemic glucocorticoid potencies are wanted. Therefore, structure-activity studies were performed in rat models to investigate what influences the type of substitution in the 16 alpha, 17 alpha-acetal group and the introduction of fluorine in the 9 alpha- or the 6 alpha, 9 alpha-positions have on the topical and the systemic activities, respectively. The introduction of an unsymmetrical 16 alpha, 17 alpha-acetal group (named acetal type B) markedly enhanced the topical anti-inflammatory potency compared with that of the conventional 16 alpha, 17 alpha-acetonide group (named acetal type A). Both acetal types had a similar systemic glucocorticoid potency, however, 9 alpha-Fluoro and especially 6 alpha, 9 alpha-difluoro substitution, on the other hand, enhanced the systemic glucocorticoid activity more than they raised the topical anti-inflammatory potency. Optimal topical to systemic activity ratio was obtained with a nonhalogenated corticoid of acetal type B structure. This compound, budesonide, had at least the same high topical anti-inflammatory potency as fluocinolone acetonide but was about 10 times less potent than this reference to induce systemic glucocorticoid actions. Its lower systemic activity is probably due to a more rapid biotransformation in the liver.