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Prednisolone measurement in human serum using liquid chromatography tandem mass spectrometry.

Prednisolone is a commonly prescribed corticosteroid used in the treatment of many diseases. Despite high doses of prednisolone, some patients appear to have subtherapeutic concentrations of the drug. It would be useful to measure prednisolone in this group to determine if they have poor absorption or compliance. Hence, we have developed a liquid chromatography-tandem mass spectrometry method for the determination of prednisolone in serum. Chromatography was performed using a C18 column, giving a retention time for both prednisolone and deuterated prednisolone (internal standard) of 1.6 min. Two transitions were monitored for both prednisolone and deuterated prednisolone. These were m/z 361.2 > 343.0 and m/z 361.2 > 146.9 for prednisolone, and m/z 367.2 > 349.0 and m/z 367.2 > 149.9 for the internal standard. The intra- and inter-batch imprecision was < 7% in both cases over a concentration range of 62.5-750 microg/L. The imprecision at the lower limit was 8%, the lower limit of quantitation was determined to be 30 microg/L and the method was linear up to 5000 microg/L. The method allows rapid prednisolone analysis because of a simplified sample extraction step, and has a cycle time of 3.5 min.

Chromatography, High Pressure Liquid↗

Effect of D-003, a mixture of very high molecular weight aliphatic acids, on prednisolone-induced osteoporosis in Sprague-Dawley rats.

BACKGROUND: Drugs inhibiting cholesterol biosynthesis may affect bone metabolism through inhibition of the mevalonate pathway resulting in the inhibition of protein prenylation required for osteoclast activity. D-003 is a mixture of high molecular weight aliphatic primary acids purified from sugar-cane (Saccharum officinarum) wax, with cholesterol-lowering effects demonstrated in experimental and clinical studies. D-003 inhibits cholesterol biosynthesis through indirect regulation of HMG-CoA reductase activity. A previous study demonstrated that D-003 prevented bone loss and bone resorption on ovariectomy-induced osteoporosis in rats. Corticosteroid-induced osteoporosis is the result of changes affecting calcium homeostasis, but the hallmark of corticosteroid-induced bone loss is the direct effects on bone cells, such as inhibition of osteoblastogenesis, promotion of apoptosis of osteoblasts and osteocytes, and decrease in bone formation. OBJECTIVE: To determine whether D-003 could prevent the bone loss induced with prednisolone in Sprague-Dawley rats. METHODS: Rats were randomly distributed in five groups (ten rats per group): a sham-operated control and four groups orally treated with prednisolone 6 mg/kg for 80 days; a positive control orally treated with vehicle; and three groups orally treated with D-003 at 5, 25 and 200 mg/kg, respectively. Rats were killed, bones removed and histological variables of bone resorption and formation studied for histomorphometry. RESULTS: Compared with the sham group, prednisolone significantly (p < 0.01) reduced trabecular bone volume (TBV), while D-003 significantly (p < 0.001) and dose-dependently prevented the prednisolone-induced reduction of TBV. Treatment with prednisolone lowered (p < 0.001) trabecular thickness (TbTh) and number (TbN), while increasing (p < 0.001) the gap between trabeculae. D-003 (5, 25 and 200 mg/kg/day) significantly (p < 0.001) and dose-dependently prevented the reduction of TbTh and TbN and the increase of trabecular gap induced with prednisolone. Treatment with prednisolone increased both the surface and number of osteoclasts compared with sham (p < 0.001). D-003 (5-200 mg/day), however, prevented this effect (p < 0.001 for all comparisons). D-003 also prevented (p < 0.001) the reduction of osteoblast surface (ObS/BS) induced by prednisolone. Osteonecrotic areas were observed in all positive controls, but in none of the sham animals. Positive controls showed hypertrophy of bone marrow adipocytes and lipid-laden pluripotential stromal cells in bones. A significant and dose-dependent reduction of the frequency of animals showing prednisolone-induced osteo-necrosis was observed across the doses of D-003 (5, 25 and 200 mg/kg) investigated here. CONCLUSIONS: D-003 (5, 25 and 200 mg/kg) prevented trabecular bone loss and femoral neck osteonecrosis induced with prednisolone in Sprague Dawley rats, also increasing osteoblast surface and reducing bone resorption parameters. These results suggest that D-003 could be useful for managing corticosteroid-induced osteoporosis.

Animals↗

Prednisolone pharmacokinetics and protein-binding in patients with portosystemic shunt.

The pharmacokinetics and protein-binding of orally administered prednisolone have been studied in seven patients with chronic liver disease and portosystemic shunts. The peak prednisolone serum concentration and the time of peak prednisolone concentration were similar to those found in normal subjects, indicating that there is no clinically significant first-pass metabolism of prednisolone. The elimination half-time and the extent of bioavailability of total prednisolone tended to be lower in the patients, and the extent of free, unbound prednisolone higher, but the differences were not statistically significant. The patients had a significantly lower serum protein-binding of prednisolone than the controls. Despite the decreased protein-binding in the patients, however, the results indicate that changes occur in the pharmacokinetics of prednisolone that tend to reduce the bioavailability of free, biologically active prednisolone towards that seen in healthy subjects. Reduction of the prednisolone dose is therefore not indicated in patients with portosystemic shunt and chronic liver disease, even in the presence of hypoalbuminemia.

Administration, Oral↗

Low dose prednisolone reduces CD4+ T cell loss in therapy-naive HIV-patients without antiretroviral therapy.

BACKGROUND: A favorable development of CD4+ T cells was noticed in therapy-naive HIV-patients without antiretroviral therapy (ART) taking 5 mg prednisolone daily. Based on these encouraging observations, prednisolone therapy in further HIV-patients without antiretroviral therapy was initiated. OBJECTIVE: To evaluate the effect of low dose prednisolone on therapy-naive HIV patients without antiretroviral therapy. METHODS: A retrospective analysis has been conducted comparing the development of CD4+ T cells, viral load and clinical outcome in all therapy-naive HIV-patients with (n = 65; CD4 > or =300/microl) or without (n = 136; CD4 > or =300/microl) prednisolone treatment for > or =6 months. RESULTS: After 3 years, therapy-naive patients on prednisolone therapy showed a CD4+ T cell increase of +50.1/microl whereas in the untreated group a decrease of -186.1/microl (p = 0.0021) was noted. After 12 months, nearly twice as much untreated patients experienced a first-time CD4+ T cell loss of >100/microl or initiation of HAART due to clinical development compared to prednisolone-treated patients (64.1% vs. 35.0%). CD4+ T cell increase was associated with viral load at baseline: Patients with lower viral loads at baseline (<30,000 copies/ml) showed a favorable development with statistically significant less drop-outs (defined as HAART-onset and/or prednisolone discontinuation for the prednisolone group) than patients with higher viral loads at baseline in the first 3 years in the prednisolone group. - CONCLUSION: Low dose prednisolone seems to be associated with a stabilization of CD4+ T cell count in therapy-naive HIV patients resulting in a pronounced prolongation of the potential time without HAART for many HIV patients.

CD4 Lymphocyte Count↗

Excretion of [3H]prednisolone in clinically normal and experimentally infected bovine udders.

The excretion rate of [3H]prednisolone from clinically normal and experimentally infected udders of 10 lactating cows was studied. Each quarter of 6 cows was injected with a single dose of [3H]prednisolone mixed with non-radioactive prednisolone equivalent to 10 mg in 10 ml of peanut oil base. Each of the remaining 4 cows was given 40 mg of nonradioactive prednisolone and [3H]prednisolone in 60% ethanol IV. Control and postadministration samples of blood, milk, and urine were examined for radioactivity. The effects of [3H]prednisolone were evaluated in the same cows, first in clinically normal udders, then 2 weeks later in udders experimentally infected with Streptococcus agalactiae. Absorption and elimination of prednisolone were the same before and after induced infection. Within 3 hours after intramammary injection, 95% of the labeled prednisolone was absorbed systemically, less than 5% of this dose was recovered in milk, and 29% was excreted in urine. After IV injection of [3H]prednisolone, less than 0.2% of the total radioactivity was recovered in milk and less than 46% was excreted in urine. Clinical mastitis induced by S agalactiae was moderate. Circulating blood leukocytes and somatic cells in the milk of normal cows remained essentially unchanged. The leukocyte response to induced infection was rapid in blood and milk. Large numbers of leukocytes were noticed in the milk and a severe leukopenia occurred. Prednisolone treatment did not alter the number of somatic cells in milk or reduce the inflammatory response of experimentally infected cows.

Animals↗

Dexamethasone and prednisolone in the horse: pharmacokinetics and action on the adrenal gland.

Pharmacokinetics of dexamethasone and prednisolone were studied in 6 horses given dexamethasone alcohol (IV or IM) or dexamethasone 21-isonicotinate as a solution IV or IM (50 micrograms/kg of body weight), prednisolone 21-sodium succinate IV or IM (0.6 mg/kg of body weight), or prednisolone acetate IM (0.6 mg/kg of body weight). Plasma concentrations were determined using a high-performance liquid chromatographic method. After dexamethasone alcohol (IV) or dexamethasone 21-isonicotinate (IV), the half-life of elimination was similar (53 minutes) for both formulations. After dexamethasone (alcohol and isonicotinate, IM), concentrations were low or nondetected. After prednisolone 21-sodium succinate (IV), the half-life of elimination (99.5 minutes) was significantly (P less than 0.01) longer than that for dexamethasone. After prednisolone 21-sodium succinate (IM), absorption was rapid and bioavailability was high. After prednisolone acetate (IM), absorption was slow and prednisolone was present in plasma for about 7 days. Due to the nonlinearity of prednisolone kinetics, a bioavailability higher than 100% was obtained. The basal plasma hydrocortisone concentration was approximately 70 ng/ml. After dexamethasone (IV or IM), plasma hydrocortisone values decreased after a 2-hour delay and returned to base line after a 3 to 4 day delay. After prednisolone 21-sodium succinate (IV or IM), plasma hydrocortisone decreased immediately (IV) or rapidly (IM) and returned to base line after a 24-hour delay. After prednisolone acetate (IM), plasma hydrocortisone decreased for up to 21 days.

Absorption↗

Changes in prednisolone pharmacokinetics and protein binding during treatment with rifampicin.

Prednisolone pharmacokinetics and protein binding were studied after i.v. injection before and after three weeks of rifampicin therapy. The elimination half-time for prednisolone fell by 44.8% +/- 8.1% (p less than 0.01) and the area under the time-concentration curve by 47.5% +/- 7.3% (p less than 0.01). The reduction in area under the time concentration curve of free, non-protein bound prednisolone was 56.5% +/- 9.8% (p less than 0.01). The reduction in AUC was greater (p less than 0.05) for free prednisolone than for total prednisolone because of non-linear protein binding of prednisolone. The total body clearance of prednisolone increased from 73.5 +/- 14.6ml/min to 142.7 +/- 35.8ml/min (p less than 0.01). There was no change in the volume of distribution of prednisolone. Because of the marked reduction in the extent of bioavailability of total, and especially free, prednisolone, dosage adjustments should be made accordingly if prednisolone and rifampicin are prescribed concomitantly.

Adult↗

Prednisolone clearance at steady state in dogs.

The purposes of this study were: 1) to determine in dogs under steady-state conditions whether prednisolone clearance increases with increasing dose as has been suggested from results obtained under nonsteady-state conditions in man and 2) to determine whether the prednisolone to prednisone conversion, apparently resulting from 11 beta-hydroxydehydrogenase, is saturable. Six dogs were given four different zero-order infusions of prednisolone resulting in steady-state levels from 23 to 5884 ng/ml.Prednisone, total and free prednisolone levels were assessed by high-pressure liquid chromatography and equilibrium dialysis. Total and unbound prednisolone clearances were calculated by dividing the infusion rate by the total or unbound prednisolone concentration at steady state. Both total and unbound prednisolone clearance exhibited a slight tendency to decrease (P < .05) with increasing prednisolone steady-state levels. The conversion of prednisolone to prednisone, defined by the prednisolone/prednisone ratio, exhibited saturable characteristics which, when data for all dogs was fitted to a Michaelis-Menten type equation (r2 = 0.938), gave a Km of 658 ng/ml, i.e., total prednisolone concentration at half-maximal saturation.

Animals↗

Preparation of prednisolone-appended alpha-, beta- and gamma-cyclodextrins: substitution at secondary hydroxyl groups and in vitro hydrolysis behavior.

The carboxyl group of prednisolone 21-hemisuccinate was conjugated to one of the hydroxyl groups of alpha-, beta-, and gamma-cyclodextrins using a coupling agent, carbonyldiimidazole. The direct coupling produced prednisolone-appended cyclodextrin conjugates in which the drug is selectively introduced at one of the secondary hydroxyl groups of cyclodextrins through an ester linkage. The aqueous solubility (> 50% w/v at 25 degrees C) of these conjugates was much higher than those of prednisolone and its 21-hemisuccinate. Prednisolone was slowly released from the conjugate: the percents of prednisolone and its hemisuccinates released from the alpha-, beta-, and gamma-cyclodextrin conjugates were 49, 57, and 85%, respectively, for 24-h. The release pathway is proposed to be via two fast acyl migrations between the 2- and 3-hydroxyl groups of cyclodextrins and between the 21- and 17-hydroxyl groups of prednisolone. The slow release of prednisolone from the ester conjugates was in sharp contrast to the fast release of the prednisolone amide conjugate reported previously. Because of relatively slow and/or site-specific release properties, the present prednisolone-appended cyclodextrin conjugates may be of value as an orally administered delayed-release and/or colon-specific prodrug.

Cyclodextrins↗

Effect of the anti-inflammatory agent tenidap on the pharmacokinetics and pharmacodynamics of prednisolone.

The effect of tenidap, a new nonsteroidal anti-inflammatory agent, on the pharmacokinetics and pharmacodynamics of prednisolone was studied in healthy male subjects. In a randomized crossover study, 12 subjects received either tenidap sodium 120 mg daily or placebo orally for 28 days. On day 21, each subject received a single dose of either 0.8 mg/kg oral prednisone or 0.66 mg/kg intravenous prednisolone followed by the other steroid on day 28. Blood and urine samples were collected, and the pharmacokinetic parameters of prednisone and prednisolone were determined in each treatment period. Pretreatment with tenidap did not cause any significant changes in the overall disposition of prednisone or prednisolone. For example, for free prednisolone, the intravenous area under concentration was 1,144 +/- 195 ng.h/mL and 1,244 +/- 140 ng.h/mL, and the systemic availability after oral prednisone was 53 +/- 10% and 51 +/- 12% with placebo and tenidap, respectively. The renal clearance of prednisolone was significantly reduced after tenidap pretreatment, however (from 143 to 77 mL/min/1.73 m2). The suppression of plasma cortisol and whole blood histamine levels were analyzed to evaluate the potential pharmacodynamic interactions between tenidap and prednisolone. There were no significant changes in the pharmacodynamic parameters between placebo and tenidap groups. The excretion of less than 20% of the dose of prednisolone in urine makes the overall effects of tenidap on prednisolone kinetics and dynamics of inconsequential clinical importance.

Adolescent↗

Effects of indomethacin on the pharmacokinetics and pharmacodynamics of prednisolone in rats.

The effect of indomethacin on the disposition of prednisolone and the induction of tyrosine aminotransferase (TAT) was examined in male Sprague-Dawley rats. Rats were pretreated with either indomethacin (5 mg/kg, intraperitoneally) or phosphate buffered saline (control) twice daily for 6 days followed by a single dose of prednisolone. Blood samples were collected after prednisolone administration. In separate animals, hepatic TAT activity (pharmacologic effect) was measured 4 h after the prednisolone dose. In addition, the effect of indomethacin on the in vitro protein binding of prednisolone was examined in pooled rat and human plasma. The clearance and apparent volume of distribution of prednisolone in the control and indomethacin-treated animals were similar, averaging 4.71 versus 4.05 L/h/kg and 1.37 versus 1.33 L/kg, respectively. The elimination half-life was 0.48 h in both groups. Indomethacin also did not affect the protein binding of prednisolone in rat or human plasma. However, indomethacin pretreatment increased the hepatic TAT activity induced by prednisolone. These studies indicate that indomethacin may affect the pharmacological effects of prednisolone without influencing its pharmacokinetics.

Animals↗

Prednisolone excitation of medial vestibular nucleus neurons in cats.

An electrophysiological study was performed to determine whether prednisolone hydrochloride directly influenced neuronal activities of the medial vestibular nucleus (MVN) in alpha-chloralose-anesthetized cats. Single neuronal activities of MVN were recorded extracellularly with a glass-insulated silver wire microelectrode attached along a seven-barreled micropipette. Each barrel was filled with prednisolone, glutamate, glutamic acid diethylester (GDEE) or CoCl2. Except for prednisolone, which was administered both intravenously and microiontophoretically, other chemicals were applied microiontophoretically to the immediate vicinity of the target neurons. These MVN neurons were classified as type I and II neurons according to their responses to horizontal and sinusoidal rotations. Intravenous prednisolone (up to 5 mg/kg) enhanced spontaneous and rotation-induced neuronal firings of both type I and II neurons in a dose-dependent manner. In a similar tendency, microiontophoretically applied prednisolone (50-200 nA) dose-dependently increased spontaneous and rotation-induced firings of both type I and II neurons. Microiontophoretic GDEE, a non-selective glutamate receptor antagonist, inhibited glutamate- and rotation-induced neuronal discharges without affecting prednisolone-induced increases in neuronal responses of MVN. In addition, iontophoretically applied CoCl2, a Ca2+ channel blocker, did not affect prednisolone-, glutamate- and rotation-induced neuronal findings of MVN. These results suggest that prednisolone induces excitation of type I and II neurons, probably by acting directly on the membrane of MVN neurons. Thus, glucocorticoids such as prednisolone may be effective for the treatment of vertigo resulting from hypofunction of vestibular nucleus neurons.

Animals↗

Dose-dependent pharmacokinetics of prednisolone in normal and adrenalectomized rats.

The pharmacokinetics of prednisolone after 5- and 50-mg/kg doses given as the sodium succinate salt was examined in normal and adrenalectomized rats. Prednisolone, prednisone, and corticosterone concentrations in plasma were determined by HPLC and free prednisolone measured by equilibrium dialysis. Prednisolone sodium succinate was rapidly and completely hydrolyzed to prednisolone as indicated by the absence of the ester from plasma within 5 min after intravenous injection. Prednisolone was rapidly metabolized to prednisone, while corticosterone concentrations in normal rats declined rapidly and were undetectable by 1 hr. Adrenalectomy had no effect on the disposition and protein binding of prednisolone. Dose, however, had a marked effect on prednisolone pharmacokinetics, with mean plasma clearance decreasing from 6.18 to 3.07 L/h per kg and mean steady-state volume of distribution decreasing from 2.14 to 1.05 L/kg from the lower to higher steroid dose. Half-life (0.50 hr) and mean residence time (0.35 hr) were unaffected by dose. Prednisolone plasma protein binding was nonlinear due to saturation of transcortin binding. Changes in pharmacokinetic parameters were not related to the nonlinear plasma binding, but were more likely caused by saturation of elimination pathways and tissue binding sites.

Adrenalectomy↗

Nonlinear plasma protein binding and haemodialysis clearance of prednisolone.

The impact of nonlinear plasma protein binding of a drug on its removal by haemodialysis has been quantified. Prednisolone 10-100 mg was given i.v. to 10 renal transplant patients on haemodialysis for acute tubular necrosis. Dialysate and afferent and efferent blood samples were collected simultaneously in 67 instances. Total and unbound prednisolone in plasma and its total concentration in blood and dialysate were assessed by high performance liquid chromatography and equilibrium dialysis. The amount of prednisolone lost, as measured directly in the dialysate (21.8 +/- 4.4 micrograms/min, mean +/- SE), was predictable from the afferent-efferent blood concentration differences (20.1 +/- 4.8 micrograms/min), but not from measurements of total afferent-efferent prednisolone concentrations in plasma (13.1 +/- 3.0 micrograms/min). The amount of prednisolone lost in the dialysate increased linearly with unbound (r2 = 0.96) and hyperbolically with the total prednisolone concentration in plasma. The latter hyperbolic relationship is adequately described by the equation for nonlinear plasma protein binding, using the affinity and capacity constants of albumin and transcortin for prednisolone (r2 = 0.98). Thus, the haemodialysis clearance of total prednisolone is concentration-dependent, while the clearance of unbound prednisolone is constant (76 ml/min). Free clearance values or measurements of afferent-efferent blood concentrations are mandatory for a drug showing nonlinear plasma protein binding in order to predict the amount lost in the dialysate.

Blood Proteins↗

Receptor-mediated prednisolone pharmacodynamics in rats: model verification using a dose-sparing regimen.

Our receptor/gene-mediated model of corticosteroid action was tested and extended by examining the pharmacokinetics/dynamics of multiple low doses vs. a single higher dose of intravenously administered prednisolone in adrenalectomized male Wistar rats. Low-dose rats received 3 bolus doses (5 mg/kg) of prednisolone at 0, 0.5 and 1.0 hr. High-dose animals were given a single 25 mg/kg dose of prednisolone. Both regimens were expected to produce equivalent net responses based on model predictions. Control rats were not dosed. The profiles of free hepatic cytosolic glucocorticoid receptors and the hepatic tyrosine aminotransferase (TAT) enzyme were examined. Plasma prednisolone concentrations showed bi-exponential decline for both doses using pooled animal data. Clearance of total plasma prednisolone was 4.16 and 3.21 L/hr per kg in low- and high-dose groups. Volume of distribution at steady state (approximately 1.50 L/kg) and central volume (approximately 0.6 L/kg) were similar for both groups. Receptor levels from 5-16 hr stabilized at 64% of the 0-hr control value. Receptor and TAT profiles were essentially superimposable for both dosing groups. Our previous model was used to simultaneously describe prednisolone plasma concentrations, hepatic receptors, and TAT activity. The ability of total plasma prednisolone (Cp), corticosteroid binding globulin (CBG)-free plasma prednisolone (CCBG), and free plasma prednisolone (CF) to describe the kinetics/dynamics were examined. The CF values produced optimum fitting of all receptor data. The similarity of the two dosing groups supports the view that appropriately timed doses of a steroid can be used in an optimally efficacious manner by first filling all receptor sites and then replacing steroid as receptors are expected to recycle from nuclear/DNA binding sites as the steroid is eliminated.

Adrenalectomy↗

Prednisolone disposition in steroid-dependent asthmatics.

A 40-mg intravenous dose of prednisolone was given as prednisolone phosphate to seven severe steroid-dependent asthmatics and to 13 healthy volunteers to determine if the large prednisone requirements of these patients were a function of the disease, cellular response, or rapid clearance of prednisolone. Plasma concentrations of prednisolone, prednisone, and cortisol were determined by high-performance liquid chromatography over an 8-hr test period. Circulating eosinophil concentrations were monitored concurrently. The apparent half-lifes of prednisolone in the asthmatics and normals were 3.33 +/- 0.71 and 3.25 +/- 0.58 hr (mean +/- SD). The apparent plasma clearances of prednisolone were 201 +/- 54 and 198 +/- 38 ml/min/1.73 m2 and the apparent volumes of distribution were 50.8 +/- 11.7 and 53.5 +/- 13.5 L/1.73 m2 for the asthmatic and normal groups, respectively. When the concentration-dependent binding of prednisolone to plasma protein was examined, no differences in the apparent clearances of unbound drug were found between the two groups. The eosinopenic response to prednisolone was similar in the steroid-dependent asthmatics and healthy normal volunteers. These studies indicate that binding, distribution, and clearance of prednisolone are not responsible for the large prednisone requirement of some steroid-dependent asthmatics. Differences in steroid-receptor sensitivity or in severity or pathophysiology of the disease state more likely account for the need for large prednisone dosages in these patients.

Adolescent↗

A randomised double-blind placebo-controlled trial of prednisolone therapy in HBeAg and HBV DNA positive Chinese patients with chronic active hepatitis B.

Forty-one hepatitis B e antigen (HBeAg) and hepatitis B virus (HBV) DNA positive Chinese patients with chronic active hepatitis B were randomized to receive either prednisolone or placebo oral for 8 weeks. The prednisolone group received 60 mg daily for 2 weeks, 40 mg for 2 weeks, 20 mg for 2 weeks, 10 mg for 1 week and 5 mg for 1 week. In 18 patients receiving prednisolone, serum HBV DNA levels rose during the course of therapy, but dropped abruptly within 1 month of cessation of treatment. Conversely, their serum alanine aminotransferase (ALT) levels decreased during high doses of prednisolone therapy, and then became transiently elevated during the period of withdrawal of prednisolone. At 1 year from initial treatment, the serum HBV DNA and ALT levels were similar between the groups of patients treated with prednisolone or placebo. In the prednisolone treated group, 66.7% of patients became HBV DNA negative, 50% became HBeAg negative, and 33.3% seroconverted to antibody to HBeAg (anti-HBe). In the placebo treated group, 60.9% of patients became HBV DNA negative, 60.9% became HBeAg negative, and 56.5% seroconverted to anti-HBe. Hepatic decompensation was not noted in any of the prednisolone-treated patients. Thus, the effects of the withdrawal prednisolone therapy on serum ALT and HBV DNA levels was temporary, and no differences in serum viral markers or biochemical parameters of liver inflammation between these two groups were noted at the 1 year follow-up period.

Adult↗

Immunosuppressive activity of prednisone and prednisolone and their metabolic interconversion in the mixed lymphocyte reaction.

The immunosuppressive activities of prednisolone, prednisone and cortisol were assessed and compared using a modified micro-2-way mixed lymphocyte reaction (MLR) assay. As measured by the inhibition of the MLR on day 3, prednisolone was 2.40 +/- 0.98 times more potent than cortisol: The average EC50S for prednisolone and cortisol were 28.25 +/- 7.8 ng/ml and 63.25 +/- 16.88 ng/ml, respectively. Prednisone (10 - 1000 ng/ml) had little or no immunosuppressive activity and did not affect the inhibition due to prednisolone or cortisol. Although, prednisone was inactive in the MLR, it was slowly being converted to prednisolone by 11-hydroxylation. MLR cultures with starting prednisone concentrations of 100, 200, 500, 1000 and 2000 ng/ml, contained 28, 34, 46, 50 and 81 ng/ml of prednisolone, respectively, on day 3 of the culturing period. The reverse reaction, the conversion of prednisolone to prednisone, did not occur. The inactivity of prednisone despite a significant conversion to its biologically active 11-hydroxyl metabolite, prednisolone, suggests the importance of the duration and timing of prednisolone's presence to immunosuppressive activity in the MLR culture.

Dose-Response Relationship, Drug↗