Analysis of prednisolone in plasma by high-performance liquid chromatography

The use of prednisolone versus dual-release hydrocortisone in the treatment of hypoadrenalism

The introduction of adrenocortical extract in 1930 improved the life expectancy of hyhpoadrenal patients, with further increases seen after the introduction of cortisone acetate from 1948. Most patients are now treated with synthetic hydrocortisone, and incremental advances have been made with optimisation of daily dosing and the introduction of multidose regimens. There remains a significant mortality gap between individuals with treated hypoadrenalism and the general population. It is unclear whether this gap is a result of glucocorticoid over-replacement, under-replacement or loss of the circadian and ultradian rhythm of cortisol secretion, with the risk of detrimental excess glucocorticoid exposure at later times in the day. The way forwards will involve replacement of the diurnal cortisol rhythm with better glucocorticoid replacement regimens. The steroid profile produced by both prednisolone and dual-release hydrocortisone (Plenadren), provide a smoother glucocorticoid profile of cortisol than standard oral multidose regimens of hydrocortisone and cortisone acetate. The individualisation of prednisolone doses and lower bioavailability of Plenadren offer reductions in total steroid exposure. Although there is emerging evidence of both treatments offering better cardiometabolic outcomes than standard glucocorticoid replacement regimens, there is a paucity of evidence involving very low dose prednisolone (2-4 mg daily) compared to the larger doses (~7.5 mg) historically used. Data from upcoming clinical studies on prednisolone will therefore be of key importance in informing future practice.

Development of a sensitive and selective method for the quantitative analysis of cortisol, cortisone, prednisolone and prednisone in human plasma

A highly selective, sensitive and robust LC-MS/MS method was developed for the simultaneous quantification of cortisol, cortisone, prednisolone and prednisone in human plasma. Prednisolone, cortisol and cortisone have similar fragmentation pattern. These three compounds were chromatographically separated, thus eliminating the inherent interference that fragments derived from the M+2 and M isotopes of prednisolone contribute in the MRM channels of cortisol and cortisone, respectively. Additionally, by using a small particle (1.8 microm) analytical column, interferences present in the plasma samples from post-transplant recipients were successfully resolved from cortisol after a simple extraction consisting of protein precipitation, evaporation and reconstitution. The chromatographic separation was achieved on a Zorbax-SB Phenyl column under isocratic conditions during a run time of 8 min. Intra-run and inter-run precision and accuracy within +/-15% were achieved during a 3-run validation for quality control samples at five concentration levels in charcoal-stripped plasma as well as in normal plasma, over a 500-fold dynamic concentration range. The lower limit of quantitation was 0.500 ng/mL for cortisone and prednisone, 1.00 ng/mL for cortisol and 2.00 ng/mL for prednisolone. The performance of the small particle column was maintained during more than 1200 injections in terms of peak retention time, symmetry and backpressure.

Liquid chromatographic analysis of prednisolone, prednisone and their 20-reduced metabolites in perfusion media

A reversed-phase liquid chromatographic assay was developed to quantitate prednisolone, prednisone and the 20 alpha-dihydro and 20 beta-dihydro reduced metabolites of both parent compounds in tissue culture media from in vitro perfusions of the human placental lobule. Steroids were extracted from perfusate, using reversed-phase cartridges, with average recoveries of 95.2% or greater. The internal standard for the analyses was 6 alpha-methylprednisolone. In this assay cortisol coelutes with prednisolone, however, no other significant interferences were found. Assay of each steroid was linear in the range 0-1 microgram/ml. Intra-assay coefficients of variation were measured at 10 and 750 ng/ml with ranges of 3.4% (20 alpha-dihydroprednisone) to 8.8% (20 beta-dihydroprednisolone) and 4.1% (20 beta-dihydroprednisone) to 8.8% (prednisone). The corresponding inter-assay coefficients of variation were 3.3% (20 alpha-dihydroprednisone) to 9.1% (20 beta-dihydroprednisolone) and 1.9% (prednisolone) to 3.5% (prednisone). The analyses utilized two C18 columns which were linked together and maintained at 40 degrees C.

High-performance liquid chromatographic determination of prednisolone and its steroid 21-oate ester derivatives in rat plasma: pharmacokinetic applications

A high-performance liquid chromatographic (HPLC) technique was developed for the determination of prednisolone and its local anti-inflammatory steroid 21-oate ester derivatives in rat plasma. These new steroid esters (methyl 20 alpha- and 20 beta-dihydroprednisolonate; P4 alpha and P4 beta), developed for local use, were found to exhibit minimal systemic side effects as compared with prednisolone. The described method involves a simple organic extraction procedure and separation of steroids using a C18 reversed-phase column for pharmacokinetic study. The method allows simultaneous measurement of endogenous corticosterone following administration of P4 alpha, P4 beta, and prednisolone. The calibration curves of the steroids were linear over a wide range of concentrations (0.05 to 10 micrograms/mL). The limit of detection of the assay for all tested steroids is 10-20 ng/mL. The method is reproducible, with a coefficient of variation of less than 10% for all steroids over a wide range of concentrations. No interference from endogenous steroids nor exogenous steroids was found. The presented method is simple, rapid, specific, sensitive, and reproducible.

Estimation of prednisone intake in pemphigus vulgaris patients with the use of simple laboratory methods

Prednisone is a widely used medication in dermatology, particularly in pemphigus patients. Simple objective laboratory methods are suggested for the evaluation of prednisone intake, taking advantage of the similar chemical structure of cortisol and prednisolone. A linear correlation was found between the dose of prednisone, above 40 mg/day, free urinary prednisolone, measured with an radioimmunoassay kit for cortisol that cross-reacts with prednisolone, and 17-hydroxycorticosteroids, measured by Metcalf's method. Approximately 9% of the prednisone administered was recovered as free prednisolone and about 40% as 17-hydroxycorticosteroids. It is suggested that these simple laboratory methods constitute a useful substitute for the more costly, sophisticated methods available at present for determining levels of prednisone and prednisolone.

The nonlinear pharmacokinetics of prednisone and prednisolone. II. Plasma protein binding of prednisone and prednisolone in rabbit and human plasma

The protein binding characteristics of prednisone and prednisolone were determined in human and rabbit plasma and in a 4.7 per cent human serum albumin (HSA) solution. The influence of prednisolone on prednisone binding in human plasma was also examined. Prednisolone exhibited nonlinear binding and prednisone linear binding characteristics in both human and rabbit plasma. Prednisone binding was not influenced by the presence of prednisolone. Prednisone binding to HSA was linear but to a degree substantially lower than observed in human plasma, suggesting the possibility that prednisone binds to other proteins in human plasma. The results support the hypothesis that the protein binding characteristics of prednisone and prednisolone do not explain the reported nonlinear pharmacokinetics of prednisone.

Prednisolone pharmacokinetics in patients with rheumatoid arthritis, polymyalgia rheumatica and asthma

The pharmacokinetic profile of a single 10 mg oral dose of prednisolone was studied in three groups of six patients with rheumatoid arthritis (RA), polymyalgia rheumatica (PMR) and bronchial asthma (BA) who were already receiving steroid therapy. A fourth group of age and sex-matched normal controls was also studied. Kinetic parameters (including elimination half-life, area under the plasma concentration curve, apparent volume of distribution and total body clearance) were similar for all four groups but there was considerable inter-subject variability. The correlations between these kinetic parameters and age, body weight and serum albumin were poor. The results suggest that any differences in the effects of corticosteroids in these inflammatory diseases are unlikely to be due to pharmacokinetic factors. The duration of steroid therapy and the reduction in patient mobility would appear to be more likely explanations for the reduction in bone mass observed in patients with RA.

Simultaneous determination of prednisolone acetate, prednisolone, prednisone, cortisone and hydrocortisone in swine plasma using solid-phase and liquid-liquid extraction techniques

A high-performance liquid chromatographic (HPLC) method for the simultaneous determination of prednisolone acetate (PA), prednisolone (PO), prednisone (PN), cortisone and hydrocortisone in swine plasma is described. Extraction of the steroid mixture from swine plasma with dexamethasone as internal standard was accomplished by solid-phase extraction (SPE) or the more traditional liquid-liquid extraction (LLE) techniques. These compounds were analyzed by normal-phase HPLC with ultraviolet detection. Although a detectable sensitivity of 5 ng/ml is achieved by the SPE technique, the practical sensitivity is established as 10 ng/ml. Conversely, the practical sensitivity is 5 ng/ml for all compounds by the LLE technique. Calibration curves were found to be linear between 10 and 500 ng/ml by the SPE technique and between 5 and 100 ng/ml by the LLE technique. The average recovery of the steroids PA, PO and PN at 20 ng/ml is between 70 and 90%. PA is stable for up to 3 h in swine plasma at room temperature (22 degrees C) but is completely converted to PO within 24 h. PA is stable in swine plasma in an ice bath for over 24 h. The usefulness of this analytical technique is demonstrated by the intraperitoneal administration of 125 mg of PA to swine and the quantitative determination of PA, PO and PN in the plasma as a function of time.

Effect of aluminium phosphate on the bioavailability of cimetidine and prednisolone

Ten fasting subjects received 200 mg cimetidine orally either with water or 11 g aluminium phosphate mixture in a randomized, single dose, two-way cross-over study. Blood samples were taken for 12 h and urine was collected for 24 h. Cimetidine in plasma and urine was analysed by HPLC. There were no significant differences between the treatments with respect to peak plasma concentration, time to peak plasma concentration, area under the plasma concentration-time curve, and urinary excretion. In 12 healthy subjects the absorption of prednisolone was investigated when given alone and together with 11 g aluminium phosphate. Blood samples were taken over 16 h and prednisolone in plasma was analysed by HPLC. There were no significant differences in the values of area under curve (AUC), Cmax and tmax. The results indicate that aluminium phosphate does not reduce the bioavailability of cimetidine and prednisolone.

Determination of prednisone and prednisolone in human serum by high-performance liquid chromatography--especially on impaired conversion of corticosteroids in patients with chronic liver disease

A reliable and rapid method is described for the determination of prednisone and prednisolone in human serum by high-performance liquid chromatography, using a Zorbax-SIL column with dichloromethane-ethanol (92.5:7.5) as eluent, with UV detection at 254 nm. Metabolites and endogenous hydrocortisone did not interfere with the determination of prednisone and prednisolone. The alteration of corticosteroid concentrations in serum from patients with chronic liver diseases was studied following a single oral administration of prednisone or prednisolone (30 mg). The proposed method showed good separation of several corticosteroids and was time-saving, suitable and reliable for the routine analysis of corticosteroids in human serum.

The use of combined high performance liquid chromatography negative ion chemical ionization mass spectrometry to confirm the administration of synthetic corticosteroids to horses

Negative ion chemical ionization mass spectra of some corticosteroids have been obtained by direct syringe introduction on to the Finnigan moving belt high-performance liquid chromatography-mass spectrometer interface. Proprietary preparations based upon dexamethasone, betamethasone and prednisolone were administered to horses at therapeutic dose level. Urine samples were extracted, the extracts purified by Sephadex LH-20 chromatography and the presence of the parent steroids in the eluates was confirmed by combined high-performance liquid chromatography negative ion chemical ionization mass spectrometry using ammonia as reagent gas.

Comparison of radioimmunoassay and thin layer chromatographic assay methods for estimation of plasma prednisolone concentrations

Radioimmunoassay and thin layer chromatographic methods of assay for prednisolone in plasma have been compared. These methods are comparable in terms of ease, speed of execution, and cost. They yielded similar estimates of prednisolone concentration without important bias over the concentration range generally encountered in clinical practice and may be considered comparable for pharmacokinetic studies.

GLC analysis of hydrocortisone, triamcinolone acetonide, and desonide in culture media of mouse and human dermal fibroblasts using flame-ionization detection

A quantitative GLC assay with flame-ionization detection capable of detecting nanogram quantities of hydrocortisone, triamcinolone acetonide, and desonide in biological fluids was developed. This assay consisted of two extractions of the glucocorticoids from 1 N sodium chloride-treated cell culture media into ethyl acetate and subsequent double derivatization with methoxyamine and N-trimethylsilylimidazole. The chemical structures of methoxime-trimethylsilyl derivatives were confirmed by GLC-mass spectrometry. The methoxime-trimethylsilyl derivatives were stable for 24 hr. The applicability of this assay was demonstrated by studies of the glucocorticoid levels in L-929 and human dermal fibroblasts cell culture media over prolonged incubation (0--96 hr).

Simultaneous determination of betamethasone, betamethasone acetate and hydrocortisone in biological fluids using high-performance liquid chromatography

A sensitive, specific, reproducible and rapid high-performance liquid chromatographic method for the simultaneous quantitation of betamethasone, betamethasone 21-acetate and hydrocortisone in biological fluids is described. Hydrocortisone acetate is used as an internal standard and the samples are extracted with dichloromethane before chromatographing on a reversed-phase system. Detection at two ultraviolet wavelengths (254 nm and 240 nm) was used to assess the specificity of the system, and the sensitivity was found to be greater than 10 ng for all steroids. The speed with which this assay can be performed makes it particularly useful for pharmacokinetic studies, and plasma concentration--time profiles resulting from the administration of betamethasone phosphate and betamethasone acetate are presented.

Pharmacokinetics and bioavailability of prednisone and prednisolone in healthy volunteers and patients: a review

Limited information is available on the pharmacokinetics and bioavailability of prednisone and prednisolone in patients with different disease states. This is partly due to difficulty in measuring these drugs in biological fluids at the usual dosages prescribed to patients. This article attempts to comprehensively review these studies categorized under the following four sections: (1) bioavailability--healthy volunteers, patients with respiratory disease, patients with liver disease, patients with kidney disease, pediatric patients with various diseases, effect of antacids, effect of food, effect of other drugs (aminophylline, cholestyramine); (2) pharmacokinetics--healthy volunteers, patients with respiratory disease, patients with liver disease, patients with kidney disease, pediatric patients with various diseases, effect of other drugs, enzyme induction of steroids and the effect on the kinetics of steroids and other drugs; (3) protein binding; and (4) analytical methods. The literature is reviewed through August 1979.

High-pressure liquid chromatography of steroids

After a brief discussion of the merits and limitations of high-pressure liquid chromatography (HPLC) relative to other chromatographic methods, special problems in the application to steroids are discussed. Publications on HPLC of steroids are then discussed under the headings of individual classes, arranged generally in the order of increasing polarity.

Analysis of natural corticosteroids in adrenal extracts and in biological fluids by high-performance liquid chromatography

A liquid chromatographic procedure is described for the analysis of the principal natural corticosteroids in extracts of adrenal glands. Microparticulate silicic acid columns and gradients of methanol in chloroform are used: conditions are described for the quantitative analysis of the single principal steroidal components of adrenal extracts for pharmaceutical use and of adrenal extracts of rats. In the last case, the use of a 5-micron silica column with the appropriate gradient allows the determination of corticosterone and of 18-hydroxydeoxycorticosterone, which were identified by means of mass spectrometry on their eluates. A single analysis can be performed on the extract of 15 mg of rat adrenal tissue. For the last type of analysis, isocratic conditions on a 10-micron LiChrosorb Diol column are also described. The application of the gradient elution procedure to the analysis of steroidal compounds in human plasma is also described.

Corticosteroid analysis in biological fluids by high-performance liquid chromatography

A sensitive, specific, and reproducible high-performance liquid chromatographic assay for the simultaneous determination of prednisone, prednisolone and cortisol in biological fluids was developed with dexamethasone as the internal standard. Samples are extracted with methylene chloride, washed with sodium hydroxide and then water, and chromatographed on a microparticulate silica gel column with UV detection at 254 nm. Sensitivity was greater than 15 ng for all four steroids. Specificity was supported by use of dual wave-length UV detection and/or radioimmunoassay. The assay has been applied in pharmacokinetic studies and a typical plasma concentration--time profile for the three steroids is presented for one subject who received 50 mg of prednisone.