Acitretin, an enhancer of alpha-secretase expression, crosses the blood-brain barrier and is not eliminated by P-glycoprotein.

BACKGROUND: ADAM10 (a disintegrin and metalloproteinase 10) has been demonstrated to act as the main physiological α-secretase. Enzymatic activity of the α-secretase on the one hand prevents the formation of toxic Aß peptides and on the other hand promotes the secretion of a neurotrophic and neuroprotective amyloid precursor protein fragment (APPs-α) by cleaving the amyloid precursor protein within its Aß sequence. Enhancement of ADAM10's gene expression may therefore present a valuable therapeutic approach for the treatment of Alzheimer's disease (AD), where Aß peptides are severely involved in the pathogenesis. OBJECTIVE: In cell culture and in a transgenic mouse model of AD, retinoids led to increased ADAM10 expression and activity. We therefore endeavor to develop a clinical application of synthetic retinoids such as acitretin in AD. METHODS: The effect of synthetic retinoids on ADAM10 gene expression was analyzed by reporter gene assays in human neuroblastoma cell line SH-SY5Y. Penetrance of acitretin into the murine brain was analyzed by high-performance liquid chromatography. P-glycoprotein (P-gp) double-knockout mice with a deficiency in both isoforms, mdr1a and 1b, were used to analyze a possible role of P-gp-dependent efflux on acitretin distribution. RESULTS: Acitretin and tamibarotene are both potent activators of ADAM10 promoter activity. Acitretin crosses the murine blood-brain barrier and its level in the mouse brain is not reduced by P-gp. CONCLUSION: Synthetic retinoids and especially acitretin seem to be ideal candidates to establish an ADAM10-based AD treatment, and therefore have already entered first clinical trials.

Blood donors on teratogenic drugs and donor deferral periods in a clinical situation.

Deferral of blood donors taking teratogenic drugs is critical. From March 2008 to January 2009, we analysed stored blood specimens from donors who had taken teratogenic drugs and whose blood was transfused to women of childbearing age to determine the plasma concentration at the time of donation using high-performance liquid chromatography. In total, 167 specimens were examined. The numbers of specimens exceeding the quantification limit were 7, 39, 4, 2 and 1 for finasteride, isotretinoin, acitretin, etretinate and dutasteride, respectively. Finasteride was beyond the recommended drug deferral period in one specimen. These results may help create practical deferral policies.

Determination of isotretinoin in human plasma by high performance liquid chromatography-electrospray ionization mass spectrometry.

A rapid, sensitive and specific high performance liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method for the quantification of 13-cis-retinoic acid (isotretinoin) in human plasma has been developed. Acitretin was employed as the internal standard (IS). The analytes were chromatographically separated on a Shimadzu Shim-pack VP-ODS C18 column (150 mm × 2.0 mm I.D.) with a mobile phase consisting of acetonitrile and water (90:10, v/v). Detection was performed on a single quadrupole mass spectrometer using an electrospray ionization interface with the selected-ion monitoring (SIM) mode. The method showed excellent linearity (r=0.9989) over the concentration range of 10-1500 ng/mL with good accuracy and precision. The intra- and inter-batch precisions were within 10% relative standard deviation. The recoveries were more than 80%. The validated method was successfully applied to a preliminary bioequivalence study of isotretinoin in 20 Chinese healthy male volunteers.

Stability-indicating validation of acitretin and isoacitretin in human plasma by LC-ESI-MS/MS bioanalytical method and its application to pharmacokinetic analysis.

LC- ESI- MS/MS simultaneous bioanalytical method was developed to determine acitretin and its metabolite isoacitretin in human plasma using acitretin-d3 used as the internal standard for both analytes. The compounds were extracted using protein precipitation coupled with liquid-liquid extraction with flash freezing technique. Negative mass transitions (m/z) of acitretin, isoacitretin and acitretin-d3 were detected in multiple reactions monitoring (MRM) mode at 325.4 → 266.3, 325.2 → 266.1 and 328.3 → 266.3, respectively, with a turbo ion spray interface. The chromatographic separation was achieved on an Ascentis-RP amide column (4.6 × 150 mm, 5 µm) with mobile phase delivered in isocratic mode. The method was validated over a concentration range of 1.025-753.217 ng/mL for acitretin and 0.394-289.234 ng/mL for isoacitretin with a limit of quantification of 1.025 and 0.394 ng/mL. The intra-day and inter-day precisions were below 8.1% for acitretin and below 13.8% for isoacitretin, while accuracy was within ±7.0 and ±10.6% respectively. For the first time, the best possible conditions for plasma stability of acitretin and isoacitretin are presented and discussed with application to clinical samples.

Pregnancy outcome of women transfused during pregnancy with blood products inadvertently obtained from donors treated with acitretin.

We assessed the pregnancy outcome of nine women inadvertently transfused with acitretin-contaminated blood products in South Korea. A total of 18 women matched to cases by age, gravidity, and singleton- or twin-pregnancy, and who were transfused with blood products not contaminated with acitretin, was also recruited. There were nine babies born in the case group. No differences (p > 0.05) were observed between cases and controls in the gestational age at delivery (38.3 +/- 1.6 weeks vs 37.8 +/- 2.2 weeks), birth weight (3,146 +/- 874 g vs 3,106 +/- 568 g), rate of pre-term deliveries (22.2% vs 11.1%) and rate of low birth weight (<2,500 g) (33.3% vs 16.7%). There was no case of malformation or neurological abnormalities born in either group. In conclusion, inadvertent exposure to acitretin-contaminated blood products was not associated with adverse pregnancy outcomes, probably because of the removal of acitretin and etretinate during the manufacturing process of blood products.

A fully validated HPLC method for the simultaneous determination of acitretin and etretinate in plasma and its application to a pharmacokinetic study in healthy Korean subjects.

OBJECTIVE: Acitretin is used for the treatment of psoriasis. The purpose of this study was to validate an HPLC method for the determination of acitretin and etretinate and to investigate the pharmacokinetic characteristics of acitretin in healthy Korean subjects. MATERIALS AND METHODS: Plasma samples or calibrators were mixed with acetonitrile and retinyl acetate (internal standard). Butanol: acetonitrile (1:1 v/v) and K2HPO4 were added later. After vortexing, 30 microl of the supernatant was injected directly into the analytical column of an HPLC system. The samples were separated by C18 reversed phase HPLC and UV detection was performed at 350 nm. Various assay performances were evaluated. RESULTS: The linearity of acitretin and etretinate was adequate up to 500 ng/ml (R2 = 0.9937 for acitretin and R2 = 0.9923 for etretinate). The accuracy was 89.5 - 113.5% and the precision was satisfactory (within-run CV, 4.4 - 15.8%; between-run CV, 3.3 - 17.4%). The LLOQ was 2 ng/ml and the stability and specificity were satisfactory. However, after storage at room temperature for 24 h under light exposure, the concentrations of acitretin and etretinate decreased by 26.0 - 66.5%. Extraction recovery was 75.1 - 91.5%. Nine healthy Korean subjects were evaluated to study the pharmacokinetics of acitretin. A single oral dose of 30 mg acitretin (Neotigason, Roche Pharmaceuticals) was given to all volunteers. The mean +/- SD pharmacokinetics of acitretin in Koreans were as follows: Cmax 148.7 +/- 93.0 ng/ml, tmax 3.2 +/- 1.3 h, t1/2 81.2 +/- 26.5 h, and AUClast 2641.9 +/- 1274.8 ng h/ml. CONCLUSION: A simple HPLC method for the simultaneous determination of acitretin and etretinate was validated, and the pharmacokinetic characteristics of acitretin in the Korean population were investigated.

Evaluation of the transfusion safety of blood products and determination of plasma concentrations of acitretin and etretinate in patients receiving transfusions.

BACKGROUND: Acitretin and etretinate are potentially teratogenic. Many people taking acitretin for psoriasis have donated blood during the deferral period in Korea. Therefore, many of the blood products from these donors treated with acitretin have been circulated in Korea. STUDY DESIGN AND METHODS: A high-performance liquid chromatography system (HP 1050, Agilent Technologies) was used to measure the drug concentrations in five blood products and in patients. Sixty patients taking acitretin were enrolled to determine their plasma drug levels. Forty-one female patients were recruited to investigate the residual plasma levels of acitretin and etretinate in relation to their teratogenicity. We calculated the elimination rate of acitretin and etretinate during the manufacturing process. RESULTS: Sixty individuals taking acitretin expressed variable acitretin (<2.0-206.8 ng/mL) and etretinate levels (<2.0-9.1 ng/mL). All patients that had a transfusion had concentrations of acitretin and etretinate lower than the lower limit of quantification (LLOQ; 2 ng/mL). The concentrations of acitretin and etretinate in five blood products were less than the LLOQ. Approximately 98.84 percent (log value, 1.94) of the acitretin and 99.93 percent (log value, 3.14) of the etretinate was eliminated during the manufacturing process of albumin. More than 99.99 percent (log values, 5.95-15.76) of acitretin and etretinate was eliminated during the manufacturing processing of immunoglobulin and blood coagulation factors. CONCLUSIONS: We confirmed the effective manufacturing processing of various blood products. We also demonstrated that individuals receiving transfusions with blood products originating from donors treated with acitretin were not at risk for significant exposure to the acitretin and etretinate.

Simultaneous determination of etretinate, acitretin and their metabolites in perfusate, perfusate plasma, bile or hepatic tissue with reversed-phase high-performance liquid chromatography.

Etretinate is a synthetic aromatic retinoid used in the treatment of psoriasis and other disorders affecting the skin. Acitretin is the primary active metabolite of etretinate. The in situ perfused rat liver model was used to study the first-pass hepatic metabolism of etretinate and acitretin and a reliable method of quantifying etretinate and its metabolites was needed. Previously published assays allow for the simultaneous quantitation of etretinate and acitretin in blood or plasma. This paper describes an accurate and reliable reversed-phase HPLC method for the determination of etretinate, acitretin and their metabolites in whole perfusate, plasma, bile and hepatic tissue.

Inability to detect plasma etretinate and acitretin is a poor predictor of the absence of these teratogens in tissue after stopping acitretin treatment.

1. Concentrations of etretinate, acitretin and its main metabolite 13-cis-acitretin were measured in plasma and subcutaneous fat samples from 37 women of childbearing age exposed to acitretin before November 1990. Twenty of the women still used acitretin and 17 had stopped therapy for a period ranging from 1 to 29 months. 2. The prevalences of detectable etretinate concentrations were 45% and 83% in plasma and subcutaneous tissue, respectively, among current acitretin users and 18% and 86% among those who had stopped acitretin therapy. Thus, inability to detect plasma etretinate is a poor predictor of the absence of etretinate in fat. 3. Acitretin and/or etretinate were detectable in fat and in some cases in plasma from women who had ceased acitretin therapy for up to 29 months. 4. We suggest that (cis)-acitretin and etretinate should be monitored in subcutaneous tissue when plasma measurements are negative. The recommended contraception period of 2 years after cessation of acitretin therapy should be reconsidered to avoid the risk of teratogenicity.

Determination of acitretin in the skin, in the suction blister, and in plasma of human volunteers after multiple oral dosing.

Several HPLC methods for quantification of acitretin and its 13-cis isomer in biological fluids have been described. Only limited data are available on determination of this drug in skin samples. Our objective was to improve the sensitivity and selectivity of existing methods to measure drug in small skin samples from humans treated with acitretin. With a new optimized mobile phase [methanol: acetonitrile (7:3, v/v), purified water with 1.5% (v/v) acetic acid, mixed in a 85:15 ratio (v/v)] and a new internal standard (arotinoid ethyl sulfone), a limit of quantification of 1 ng/g tissue was reached. Nine male volunteers were given an oral daily dose of 50 mg acitretin for up to 28 days. Blood and skin samples (punch and shave biopsies, suction blister skin, and fluid) were taken at various time points during and after treatment. Drug concentration and metabolism in plasma and skin samples appeared to be linked in that the trans-isomer concentration was always higher than the cis-isomer concentration during dosing and 3 h after the last dose. However, 7 and 14 days after the last dose in plasma and in all tissue samples (except the shave biopsy), the all-trans-acitretin concentration rapidly decreased and approached the detection limit. In the shave biopsy, the all-trans-acitretin concentration remained higher than the 13-cis-acitretin concentration. Furthermore, the elimination of two isomers from the shave biopsy was delayed.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatic enzyme induction potential of acitretin in male and female Sprague-Dawley rats.

Certain retinoids have been shown in rats and mice to induce the hepatic cytochrome P-450 enzyme system, and evidence from our laboratory suggested that acitretin, the active primary metabolite of etretinate (a retinoid used in the treatment of psoriasis) may induce its own metabolism. To test this hypothesis, male and female Sprague-Dawley rats were orally pretreated with acitretin for 18 days (10 mg/kg/day) and intravenously dosed with acitretin on day 20 (0.8-0.9 mg/kg). Serial blood samples were taken through 24 h, after which the hepatic microsomal proteins were harvested. Plasma concentrations of acitretin and its main metabolite isoacitretin were determined by HPLC, and total hepatic cytochrome P-450 concentrations and activities were determined using standard methods. Systemic clearance (17.4 +/- 2.5 and 12.1 +/- 1.6 mL/min per kg in control males and females, respectively), volume of distribution at steady state (Vss = 1568 +/- 353 and 1589 +/- 488 mL in control males and females, respectively), and mean residence time (MRT = 1.50 +/- 0.23 and 2.22 +/- 0.70 h in control males and females, respectively) were unchanged by acitretin pretreatment. Systemic clearance was 44% higher in control males than females. Concentrations of total microsomal protein (13.8 +/- 1.6 and 8.4 +/- 1.2 mg/g of liver in control males and females, respectively) and total P-450 (0.433 +/- 0.041 and 0.425 +/- 0.104 nmol/mg microsomal protein in control males and females, respectively) were also unchanged by acitretin pretreatment, as were microsomal levels of methoxy-, ethoxy-, pentoxy-, and (benzyloxy)resorufin O-dealkylation (MROD, EROD, PROD, and BROD, respectively) (control males and females, respectively, expressed as pmol of resorufin formed/min per mg of microsomal protein: MROD = 37.7 +/- 4.5 and 30.6 +/- 4.2; EROD 276 +/- 40 and 208 +/- 59; PROD = 15.2 +/- 4.5 and 5.8 +/- 1.2; and BROD 93.7 +/- 24.4 and 15.5 +/- 3.9).(ABSTRACT TRUNCATED AT 250 WORDS)

Disposition of [14C]acitretin in humans following oral administration.

The disposition of the antipsoriatic agent, acitretin, was investigated in six healthy human volunteers who each received a single, oral 50 mg dose of [14C]acitretin (50 microCi). plasma, urine, and feces were collected for 240 hr after administration. Mean values of 20.9 and 62.6% of the administered dose were recovered in the urine and feces, respectively. The terminal elimination half-life of total radioactivity from the plasma was approximately 120 hr. Extraction of pooled plasma samples followed by separation by HPLC and quantitation by liquid scintillation counting indicated that acitretin and its 13-cis-isomer, isoacitretin, were minor fractions of the total drug-related material in the plasma at most time points up to 72-hr postdose. The structures of acitretin, isoacitretin, and two other metabolites--(5E,7E)-8-(4-methoxy,2,3,6-trimethylphenyl)-2,6 -dimethyl-5,7- octadienoic acid (I) and (5E,7E)-8-(4-hydroxy-2,3,6-trimethylphenyl)-2,6-dimethyl-5,7 -octadienoic acid (II)--were confirmed by MS and cochromatography with authentic standards. I and II were major fractions of the drug-related material in the plasma at all time points. Other compounds, whose structures could not be confirmed, also account for a significant fraction of the circulating radioactivity.

Kinetics of tissue distribution and elimination of retinoid drugs in the rat. II. Etretinate.

Rats were injected with single intravenous doses of etretinate (6 mg/kg), and concentrations of the drug and its metabolites, acitretin and 13-cis-acitretin, were determined in plasma and nine tissues up to 96 hr. A newly developed sensitive method for the determination by HPLC of the three retinoids in tissues was used. Etretinate rapidly appeared in most tissues and underwent a redistribution from highly perfused organs into muscle, skin, and ultimately, adipose tissue. Tissue/plasma concentration ratios ranged from 14 to 1, with the highest value in adipose tissue. In this tissue, maximum concentration was reached after 1.5 hr and remained practically constant up to 96 hr. Etretinate was rapidly hydrolyzed to form acitretin at concentrations that surpassed those of the parent drug in plasma, liver, kidney, and brain. After 6 hr, approximately 45% of etretinate had been metabolized to acitretin and approximately 40% to unidentified metabolites. These metabolites were not observed in tissues after 6 hr postdose. The parent drug was not observed 12 hr postdose, except for 6% of the dose remaining in adipose tissue. Etretinate elimination, in most tissues, was biphasic with terminal half-lives of 41 hr in skin, 1-6 hr in other lean tissues, and 1.7 hr in plasma. A volume of distribution of 1.7 liters/kg was determined, and a clearance of 12 ml.min-1.kg-1. Etretinate is characterized by rapid metabolism, transient storage in skin, and prolonged storage at a low level in adipose tissue as a deep compartment. A comparison of the pharmacokinetics of the closely related retinoids, etretinate and acitretin, disclose very pronounced differences.

Kinetics of tissue distribution and elimination of retinoid drugs in the rat. I. Acitretin.

Rats were injected with single intravenous doses of acitretin (6 mg/kg), and concentrations of the drug and its metabolite, 13-cis-acitretin, were determined in plasma and nine tissues up to 6 hr postdose. A newly developed sensitive method for the determination by HPLC of acitretin, 13-cis-acitretin, and etretinate was used. Acitretin rapidly appeared in liver and muscle, where it underwent redistribution into skin and adipose tissue. Tissue/plasma concentration ratios of acitretin ranged from 2.8 to 0.3 in the order adipose tissue > brain, liver > lung, heart, kidney, spleen > skin, muscle. Adipose tissue storage was moderate and short-lived. The metabolite, 13-cis-acitretin, was detected in all tissues but not in plasma; it accounted for < 10% of the administered dose at any time. No etretinate could be detected as a metabolite in plasma or tissues. After 6 hr, < 1% of the dose remained in the body as acitretin and 13-cis-acitretin. Disappearance was monophasic, with an elimination half-life of 70 min in plasma and 68 +/- 9 min in the nine tissues. The volume of distribution was 0.6 liters/kg and clearance 6 ml.min-1.kg-1. Acitretin was characterized by rapid first-order elimination and the absence of storage in a deep compartment.

Conversion of acitretin to etretinate in psoriatic patients is influenced by ethanol.

Acitretin has recently been introduced to replace etretinate in the treatment of severe psoriasis due to a considerable shorter terminal half-life. The previously recommended 2-month anticonceptive period after acitretin treatment has been extended to 2 years after the detection of etretinate in certain acitretin recipients. In the present study, 10 patients with severe psoriasis were treated with 30 mg acitretin daily for 3 months. Seven patients had detectable mean steady-state plasma etretinate concentrations in the range of 2.5 to 56.7 ng/ml. Four of the patients showed teratogenic levels of plasma etretinate. Consumption of alcohol appeared to be an important contributing factor for the formation of etretinate. As judged from the dose- and body-weight-normalized AUC values (AUCcor) there was a great inter-individual variation (sixfold) in the systemic availability of acitretin. After discontinuation of therapy, the rate of elimination of both acitretin (t1/2 range 1.0 to 25.4 d) and 13-cis-acitretin (t1/2 range 1.5 to 25.7 d) was found to be related to the observed mean steady-state level of etretinate as evidenced by a longer terminal t1/2 of patients with high levels of etretinate in plasma. A mean terminal elimination half-life of etretinate was found to be 45.7 d +/- 10.6 (mean +/- SD; range 27.0 to 59.3 d). The risk of metabolic formation of etretinate in acitretin recipients makes it impossible to draw any definite conclusion with regard to recommendation of length of anticonceptive period following acitretin therapy in psoriatics. Monitoring of plasma etretinate levels in acitretin-treated fertile women is advisable.

Pharmacokinetics and drug interactions of etretinate and acitretin.

Acitretin, the metabolite of etretinate, is eliminated far more rapidly from the human body than is etretinate. It had therefore been suggested that only a short period of contraception would be required after the cessation of long-term therapy with acitretin. However, recent studies have demonstrated the presence of etretinate in the plasma of patients who were treated with acitretin. In this article we provide results from a study in our center and discuss earlier data in light of the recently discovered metabolic pathways for acitretin. Reesterification of acitretin to etretinate, however, results in a loss of the metabolic advantages of acitretin. Because of this situation the recommended contraception period after acitretin therapy has been lengthened to 2 years.

Comparative binding of etretinate and acitretin to plasma proteins and erythrocytes.

The interactions of etretinate and its main metabolite acitretin with human plasma proteins have been investigated in vitro by an erythrocyte partitioning technique that allows a quantitative estimation of the plasma and erythrocyte binding. Etretinate was extensively lipoprotein-bound (75% of plasma etretinate), with a binding constant for its main low density lipoprotein carrier of 40 x 10(6) M-1, accounting for 48% of the total plasma-bound drug. Acitretin was mainly albumin-bound (91% of plasma acitretin), with a binding constant of 0.7 x 10(6) M-1. The total plasma binding of both drugs was > 99% and, in blood, the fractions associated with erythrocytes were 14.5 and 8.1% of the total amount for etretinate and acitretin, respectively.