Plasma adriamycin and daunorubicin levels by fluorescence and radioimmunoassay

PCL-based thermo-gelling polymers for in vivo delivery of chemotherapeutics to tumors

The synthesis of a multiblock poly(ether ester urethane)s comprising poly(ε-caprolactone), poly(ethylene glycol), and poly(propylene glycol) segments is described. We found that this polymer possessed a critical thermo-gelation concentration of 4wt%. Molecular characterization of the polymer was performed in terms of molecular weight determination, chemical composition elucidation and functional group determination using GPC, NMR, and FTIR. We carried out in vitro paclitaxel and doxorubicin release studies and demonstrated that sustained therapeutic release of about 2weeks can be obtained with this system. A nude mice model of tumor was developed and intratumoral injection of therapeutic-loaded thermo-gel demonstrated that PTX-loaded thermo-gel effectively inhibited the growth of tumors.

PHB-Based Gels as Delivery Agents of Chemotherapeutics for the Effective Shrinkage of Tumors

Injectable thermogel to deliver chemotherapeutics in a minimally invasive manner and to achieve their long term sustained release at tumor sites to minimize side effects is attractive for chemotherapy and precision medicine, but its rational design remains a challenge. In this work, a copolymer with natural biodegradable poly[(R)-3-hydroxybutyrate] (PHB), hydrophilic poly(ethylene glycol), and temperature sensitive poly(propylene glycol) blocks linked by urethane linkages is designed to show thermogelling characteristics which are beneficial for minimally invasive injection and safe degradation. This thermogelling polymer possesses in vitro biocompatibility with very low cyto-toxicity in HEK293 cells. Furthermore, it is able to form the gel to achieve the controllable release of paclitaxel (PTX) and doxorubicin (DOX) by adjusting polymer concentrations. A rodent model of hepatocarcinoma has been performed to demonstrate the in vivo applications of this PHB-based thermogel. The drug-loaded thermogel has been intratumorally injected and both PTX-loaded and DOX-loaded thermogel have significantly slowed down tumor growth. This work represents the first time that injectable PHB thermogels have possessed good controllable release effect of chemotherapeutics against the in vivo model of tumors and will benefit various applications, including on-demand drug delivery and personalized medicine.

Pentoxifylline as a modulator of anticancer drug doxorubicin. Part II: Reduction of doxorubicin DNA binding and alleviation of its biological effects

Anticancer drug doxorubicin is commonly used in cancer treatment. However, drug's severe side effects make toxicity reduction important matter. Another biologically active aromatic compound, pentoxifylline, can sequester aromatic compounds in stacking complexes reducing their bioactivity. This work deals with the problem of alleviating doxorubicin side effects by pentoxifylline. We employed a wide spectrum of prokaryotic and eukaryotic cellular assays. In addition, we used the doxorubicin-pentoxifylline mixed association constant to quantitatively assess pentoxifylline influence on the doxorubicin mutagenic activity. Obtained results indicate strong protective effects of pentoxifylline towards doxorubicin, observed on bacteria and human keratinocytes with no such effects observed on the cancer cells. It may be hypothesized that, considering much shorter half-life of pentoxifylline than doxorubicin, simultaneous administration of doxorubicin and pentoxifylline will lead to gradual release of doxorubicin from complexes with pentoxifylline to reach desired therapeutic concentration. Proposed results shed light on the possible doxorubicin chemotherapy modification and its side effects reduction without the loss of its therapeutic potential.

The reduction of doxorubicin at a mercury electrode and monitoring its interaction with DNA using constant current chronopotentiometry

In this report, voltammetry with linear scan and chronopotentiometric stripping (CPS) with constant current were used for the analysis of doxorubicin (DOX) at a hanging mercury drop electrode (HMDE). CPS was used for the study of DOX in situ electrochemical reduction in adsorbed state and for ex situ (adsorptive transfer) analysis of the drug. For the first time, CPS was used to study the reversible reduction of the DOX quinine moiety at –0.45 V (vs Ag|AgCl|3 M KCl) as well as electrode processes giving rise to an irreversible signal around –1.45 V at the HMDE in 0.2 M acetate or Britton–Robinson buffers at different pH values. The dependence of the latter signal on pH revealed involvement of protonation equilibria; however, neither CV nor CPS data confirmed the catalytic character of the electrode reaction previously suggested by other authors. The CPS method was also applied to monitor the DOX interaction with double- (ds) and single-stranded (ss) DNA. In the presence of dsDNA, more pronounced changes in DOX signal intensity were observed, in agreement with a strong intercalation of the DOX redox centre into the DNA double helix.

Chemo brain (chemo fog) as a potential side effect of doxorubicin administration: role of cytokine-induced, oxidative/nitrosative stress in cognitive dysfunction

Doxorubicin (ADRIAMYCIN, RUBEX) is a chemotherapeutic agent that is commonly administered to breast cancer patients in standard chemotherapy regimens. As true of all such therapeutic cytotoxic agents, it can damage normal, noncancerous cells and might affect biochemical processes in a manner that might lead to, or contribute to, chemotherapy-induced cognitive deficits when administered either alone or in combination with other agents.

In vitro cytotoxic activity of Taxol and Taxotere on primary cultures and established cell lines of human ovarian cancer

The activity of Taxol and Taxotere was evaluated on three established cell lines and 19 primary cultures of human ovarian cancers and compared with that of cisplatin and doxorubicin. The cytotoxic activity of the different drugs was assessed with a clonogenic assay in cell lines and with a proliferative assay (based on [3H]thymidine [3H-dT] incorporation of cells grown in double-layer agarose for four days) in primary tumor cultures. The two assays run in parallel on the OVCA432 cell line provided similar ranking of activity for all the drugs. Taxotere was more cytotoxic than Taxol in two cell lines and showed the same degree of activity in one cell line. Moreover, the two drugs were more cytotoxic than cisplatin and doxorubicin in all cell lines. In primary cultures both Taxol and Taxotere were less active than cisplatin and doxorubicin. An activity by at least one of these two compounds was seen in 9 of 19 cases. Taxol was more frequently active than Taxotere and generally more potent. A direct relationship was observed between the proliferative activity of the tumor cell population and response to Taxol and/or Taxotere. In fact, cell lines that were highly sensitive to Taxol and Taxotere displayed 3H-dT labeling index (LI) values much higher than those observed in primary cultures (39% to 45% versus 0.2% to 12.6%). Again, primary cultures sensitive to Taxol and/or Taxotere were characterized by a median 3H-dT LI value about three times higher than that observed in resistant cultures (8.0% versus 2.6%).

Hepatic function and drug pharmacokinetics after total body irradiation plus bone marrow transplant

Radiation nephritis is the principle late toxicity seen after total body irradiation in barrier-maintained rats when hematologic toxicity is prevented by bone marrow transplantation. Renal dysfunction is observed for single doses as low as 7.5 Gy. Hepatic blood flow, as measured by indocyanine green clearance, is decreased after 8.5-9.5 Gy single-dose total body irradiation. Serum albumin levels are decreased after 9.5 Gy single-dose total body irradiation. Hypoalbuminemia is a symptom of hepatic damage, but can also be caused by renal damage or edema. No decrease in total serum protein is observed, indicating that proteinuria resulting from renal damage is not the cause of hypoalbuminemia. No edema and some dehydration are observed. These data indicate that hepatic damage as well as renal damage may be occurring after total body irradiation plus bone marrow transplantation. Animals given total body irradiation plus bone marrow transplantation show decreased tolerance to a wide variety of immunosuppressive and cytotoxic drugs, even when these drugs are given months after total body irradiation. Altered drug clearance after total body irradiation plus bone marrow transplantation is observed for cis-platinum, vincristine, and adriamycin. The increase in cis-platinum toxicity after total body irradiation plus bone marrow transplantation is caused by decreased renal drug clearance. The decrease in vincristine tolerance and the alterations in adriamycin and vincristine pharmacokinetics are caused by altered drug distribution after total body irradiation plus bone marrow transplantation. These results indicate that bone marrow transplant survivors may show altered clearance of, and decreased tolerance to, a wide variety of drugs that are used after bone marrow transplantation.

Structural requirements for anthracycline-induced cardiotoxicity and antitumor effects

By employing rat cardiac myocytes in culture and mouse L-1210 leukemia cells, we have compared different anthracycline analogs with respect to their ability to kill cardiac myocytes and tumor cells. Anthracyclines induced a decrease in cellular ATP and glutathione from both cardiac myocytes and L-1210 cells in a time- and concentration-dependent fashion. Moreover, the decrease in ATP in cardiac myocytes was followed by release of the cytoplasmic enzyme lactic acid dehydrogenase and of adenine nucleotides after anthracycline treatment. At very low concentrations of anthracyclines, at which ATP and glutathione were not affected, the drugs induced complete cessation of the growth of L-1210 cells. Some structural alterations in the anthracycline molecule resulted in parallel changes in antitumor activity and in cardiotoxicity. But other structural alterations resulted in dissimilar changes in antitumor activity and cardiotoxicity. Although the results indicate that the structural requirements for inducing cardiotoxicity and antitumor activity may be different, they also indicate that the mechanisms by which anthracycline causes cell death in tumor cells and cardiac myocytes may be the same.

Anthracycline antitumour agents. A review of physicochemical, analytical and stability properties

A review of physicochemical and analytical properties of anthracycline antitumour agents is presented. The following subjects are discussed: protolytic equilibria, partition and partition coefficients, self-association, adsorptive properties, metal complexation, spectroscopy and chromatography. Furthermore, the stability of anthracyclines in solutions, in pharmaceutical preparations and in biological media is discussed.

The effects of bisantrene on human platelets

Bisantrene, (9,10-anthracenedicarboxaldehyde bis [(4,5-dihydro-1H-imidazol-2yl)hydrazone] dihydrochloride) is one of a series of anthracene dicarboxaldehyde compounds in Phase II trials. Preliminary studies suggested that bisantrene has anti-platelet activity. Therefore, in vitro studies of its effects on platelets were undertaken. Bisantrene in clinically attainable concentrations of 0.625 - 10 microM, caused a 95 +/- 1% decrease in maximal platelet aggregation to collagen (1 microgram/ml), and epinephrine (5-40 microM) and 90 +/- 10% inhibition of arachidonic acid (50 micrograms/ml) induced aggregation. Collagen induced platelet shape change was not affected. Aggregation to calcium ionophore A23187 was inhibited by 10-30%. No effect on ADP induced aggregation was seen at clinically relevant bisantrene concentrations. This inhibition was time dependent, reaching a maximum when platelets were preincubated with bisantrene for 10 minutes before exposure to agonist. Inhibition persisted after bisantrene was removed by washing. To determine the mechanism of platelet inhibition, platelet prostaglandin metabolism, oxygen consumption and release reaction were measured. In the presence of drug: normal cyclooxygenase activity was demonstrated by O2 consumption studies and normal secondary wave ADP (3.2 microM) aggregation; lipoxygenase activity, by O2 consumption was also normal. There was 30-50% inhibition of thromboxane A2 synthesis induced by arachidonic acid or collagen; ADP, collagen and AA induced release of serotonin was decreased by 30-60% but was never abolished. No effect on basal platelet cAMP levels nor additive effect on PGE1 induced elevation of platelet cAMP was detectable. These data demonstrate that bisantrene has potent antiplatelet activity probably mediated by several different mechanisms. The inhibition may have important clinical and theoretical consequences.

Reversed-phase ion-pair high-performance liquid chromatography of adriamycin and adriamycinol in rat serum and tissues

An ion-pair reversed-phase high-performance liquid chromatographic method is presented for the determination of adriamycin and adriamycinol concentrations in rat serum and tissues. The scheme for developing the chromatographic conditions is discussed. A good separation of adriamycinol and adriamycin was obtained by using a high sodium lauryl sulphate concentration in the mobile phase. The retention times of adriamycinol, adriamycin and daunomycin (internal standard) were less than 3 min with no interfering peaks from endogenous constituents. A protein precipitation method was used to prepare the serum and tissue samples for injection.

Drug level monitoring: cytostatics

The present review on the quantification of cytostatic drugs has mainly been focussed on chromatographic techniques. Special attention has been paid to the precautions that have to be taken into account to ensure the selectivity and accuracy of the various methods. The various cytostatics that have been dealt with are: alkylating agents, antimetabolites, vinca alkaloids, antibiotics, cis-diamminedichloroplatinum, podophyllotoxine derivatives, and nitrosoureas.

Anticancer drug pharmacodynamics

A considerable amount of information is available on the pharmacokinetics of anticancer drugs, but much less is known of their pharmacodynamics, that is of the relationship between therapeutic or toxic response and drug concentration. Drug dosage regimens which are to achieve defined therapeutic objectives can only be designed when both the pharmacokinetic and the pharmacodynamic characteristics of a drug are known. There are a few reports in the literature of relationships in man between toxic response and pharmacokinetic parameters of anticancer drugs, and an even smaller number of reports of relationships between therapeutic response and pharmacokinetic parameters. It is suggested that the lack of pharmacodynamic information is currently limiting the application of pharmacokinetic information to cancer therapy. Ways of improving knowledge of the pharmacodynamics of anticancer drugs are suggested.

Pharmacokinetic studies in lung cancer patients

Pharmacokinetic measurements to monitor and design cytotoxic treatments in cancer patients are being used more and more in order to optimize dosage and administration schedules. Ideally, information on drug concentrations over time should help reveal dose-response correlations. The cytotoxic drugs carmustine, etoposide, cyclophosphamide, iphosphamide, cis-diammineplatinum, Adriamycin (doxorubicin), and 4'-epi-Adriamycin have been monitored on different treatment programs of patients with advanced lung cancers. The collected experience emphasizes the many individual variables encountered in clinical practice complicating the effort of correlating pharmacokinetic data with clinical results. The examples, presented on the basis of the authors' experiences, pertain to drug instability, gastrointestinal absorption, enzymatic induction in the liver, drug interaction, and drug tissue concentrations.

Relationship between plasma adriamycin levels and the outcome of remission induction therapy for acute nonlymphocytic leukemia

Plasma adriamycin and adriamycinol levels were measured in 45 patients with acute nonlymphocytic leukemia 3 h after the drug was administered. A wide range of levels as found. Plasma levels increased after the administration of each of the three daily doses of the drug. High plasma levels were associated with both death during remission induction therapy and, for patients who entered remission, long remissions.

Time dependency of adriamycin and adriamycinol kinetics

Adriamycin was administered by IV injection to seven patients with various solid tumors at a dose of 30 mg/m2 during successive courses. Extraction was carried out by the SEP-PAK method for plasma and by solvents for urine. Plasma and urinary levels of adriamycin and adriamycinol were determined by high-performance liquid chromatography over 72-h period after injection. Pharmacokinetic parameters for adriamycin and adriamycinol were calculated for each course of treatment. The results show significant inter- and intra-individual variations in the kinetics and elimination of both compounds. The analysis of pharmacokinetic data reveals a wide variability in the fluctuations observed during the successive courses in different patients. This study confirms the time-dependency of ADR kinetics.

Quantitation of adriamycin in plasma and urine: Comparative study of radioimmunoassay and high-performance liquid chromatography methods

The response of tumours to adriamycin, and the cardiotoxicity of the drug, may be related to its pharmacokinetics and plasma levels. Rapid and sensitive methods of adriamycin determination in plasma and urine samples are thus needed. A comparative study shows that high-performance liquid chromatography with fluorimetric detection is a reliable and specific method, but it is relatively slow and sometimes lacks sensitivity. A commercially-available radioimmunoassay kit is convenient, but there is a cross reaction with the major metabolise adriamycinol and unless the assay is combined with an extraction step, it gives erroneously high results.

Doxorubicin and 5-fluorouracil plasma concentrations and detectability in parotid saliva

Doxorubicin and 5-fluorouracil pharmacokinetics were studied in 19 volunteers with various advanced neoplastic diseases who received 50-90 mg doxorubicin or 600-1000 mg 5-fluorouracil intravenously, followed by plasma and parotid saliva collection over a 75 min period. The extent to which these chemotherapeutic agents are bound to plasma proteins, at concentrations chosen to approximate plasma concentrations, was measured by equilibrium dialysis. Both agents were quantitated by high-performance liquid chromatography. As reported previously, a wide range of plasma levels were found among patients receiving similar doses of either doxorubicin or 5-fluorouracil. It appears that in addition to being quickly cleared from the plasma both chemotherapeutic agents are excreted in detectable amounts in parotid saliva, a route of elimination heretofore given little or no attention. Excretion in the saliva exposes the mucosa of the upper gastrointestinal tract to 5-fluorouracil after intravenous administration and may play a part in causing stomatitis in patients receiving it by this route. Since there are huge interindividual and pronounced intraindividual differences in S/P ratios mostly not systematically related to the drugs' concentration in plasma, the concentration in parotid saliva was not useful in predicting the level of free doxorubicin or 5-fluorouracil in plasma.

Quantitation of daunorubicin and its metabolites by high-performance liquid chromatography with electrochemical detection

A selective and sensitive high-performance liquid chromatographic method was developed for the separation and quantitation of daunorubicin and its metabolites in serum, plasma, and other biological fluids. Daunorubicin and metabolites in human plasma were injected directly into the high-performance liquid chromatography system via a loop-column to pre-extract the drugs from the plasma, and quantitated against a multilevel calibration curve with adriamycin as the internal standard. The column effluent was monitored with an electrochemical detector at an applied oxidative potential of 0.65 V and by fluorescence. Daunorubicin and four metabolites were separated and characterized by this method. In a blinded evaluation of accuracy and precision, the mean coefficients of variation were 3.8, 3.6 and 9.8% at concentrations of 150, 75 and 15 ng/ml, respectively, and blank samples gave negligible readings. The amperometric sensitivity was greater than achieved by fluorescence detection, and offers an alternative method for quantitation of these compounds. The new method has a limit of detection of less than 2 ng on column, allowing quantitation of less than 10 ng/ml in plasma samples without organic extraction prior to chromatographic analysis.

Adriamycin and methyl-CCNU combination therapy in hepatocellular carcinoma: clinical and pharmacokinetic aspects

Twenty-one patients with unresectable hepatocellular carcinoma (hepatoma) were treated with adriamycin (15-45 mg/m2 q21 D) and methyl-CCNU (75-150 mg/m2 q 63 D) with dosage adjusted for hepatic dysfunction. Objective response frequency was 14% with all responses occurring in patients with normal pretreatment bilirubin levels. Median survival of all patients was 87 days. Initial bilirubin levels greater than 2 mg/dl predicted for decreased survival (median 30 days vs. 115 days, P less than 0.05). Only moderate hematologic toxicity was observed. Plasma profiles of Adriamycin and adriamycinol were determined during 11 courses of Adriamycin administration in seven of these patients. Despite moderately elevated transaminase levels (all cases) and bilirubin levels (three cases), plasma Adriamycin profiles in hepatoma patients were not elevated (terminal half-life of 30 hours) and were indistinguishable from that of non-hepatoma patients with normal liver functions. However, delayed appearance of peak levels and prolongation of terminal half-lives were routinely observed for adriamycinol, a major metabolite of Adriamycin. This resulted ina significant increase in the CXT (concentration X time) ratio of adriamycinol/Adriamycin in hepatoma patients compared with nonhepatoma patients (2.36 +/- 2.12 vs 0.76 +/- 0.31, (P less than 0.05). We conclude that the combination of relatively mild toxicity and normal Adriamycin disposition indicates unusual tolerance to Adriamycin therapy for patients with hepatoma and cirrhosis. As a result, severe dosage adjustments of Adriamycin may not be indicated for all such patients having only moderate hepatic dysfunction.

Initial observations on the effects of delta 9-tetrahydrocannabinol on the plasma pharmacokinetics of cyclophosphamide and doxorubicin

We studied the effect of THC upon the pharmacokinetics of cyclophosphamide (CTX) and doxorubicin (ADR). Plasma THC was determined by RIA. Plasma concentrations of CTX and ADR were measured by GLC and fluorescence, respectively. RIA confirmed plasma levels of THC greater than 20 ng/ml for patients who received THC. CTX half-life was not significantly changed with use of THC (7.7 +/- 3.6 hours without versus 5.25 +/- 2.6 hours with THC). ADR half-life with THC was greater than without THC (175 +/- 197 hours versus 92 +/- 92 hours, respectively). Total drug exposure as determined by areas under the curves were similar (12.4 +/- 6 microM . hr without versus 13.8 +/- 4 microM . hr with THC). These preliminary data suggest that RIA is reliable for assessing THC plasma concentrations. THC induces no apparent alterations of CTX or ADR pharmacokinetics.

Pharmacokinetics of daunorubicin after administration as free drug or as DNA complex in leukemic patients

An earlier whole-body autoradiographic study in mice revealed large differences between the tissue distribution of daunorubicin (D) after administration as free drug as as DNA-linked D. Therefore, the pharmacokinetics of D administered as free drug or linked to DNA was studied in 15 adult patients with acute non-lymphoblastic leukemia. The data obtained following infusion of free drug over either 45 or 240 min could be fitted to a two-compartment open-body model. With the D-DNA infusion considerably higher plasma concentrations were achieved, with a slower distribution and elimination from plasma than seen after the administration of free drug. this confirmed earlier animal data indicating a different pharmacokinetic behavior of D when it was administered linked to DNA. Furthermore, different pharmacokinetic parameters were obtained for D during infusion and in the post-infusion phase after administration of DNA-linked D (P less than 0.005). This finding strongly indicates that the D-DNA acts as a slow-release preparation in humans, which might modify tissue distribution and toxic side-effects of the drug.

Analysis of carminomycin in human serum by fluorometric high-performance liquid chromatography

A method is given for the determination of carminomycin (CMM) and a major metabolite carminomycinol (CMMOH) in serum from cancer patients after intravenous administration of carminomycin as the free drug. CMM and CMMOH are extracted from serum with chloroform, the extract evaporated and the residue dissolved in methanol. High performance liquid chromatography analysis utilized a C18 microBondapak reversed-phase column eluted with 0.1 mol/l acetate buffer (pH 4)-acetonitrile (60:40, v/v) with fluorescence detection. The assay is linear, reproducible, and precise with a limit of detection of 2 ng/ml. Representative serum levels of CMM and CMMOH in a cancer patients are presented.

Anthracycline assay by high-pressure liquid chromatography

A general method of analysis of anthracycline concentrations was developed. Drug is extracted from plasma with organic solvent and separated from metabolites by high-pressure liquid chromatography on an aminocyanosilica column. Detection and quantitation are by the endogenous fluorescence of compounds having an intact tetracyclic ring structure. Limits of sensitivity are 5, 1, and 5 ng/ml of plasma for doxorubicin, carubicin, and marcellomycin, respectively. The assay can be used for studying the aldo-keto reductase and reductive glycosidase reactions with anthracyclines as the substrates and for the evaluation of the clinical pharmacology or pharmacodynamics of various doxorubicin analogs.

Cis-Dichlorodiammine platinum and adriamycin therapy for advanced gynecological and genitourinary neoplasms

Cis-Dichlorodiammine platinum (DDP) 75 mg/m2 on days 1 and 8 and Adriamycin (ADR) 60 mg/m2 on day 1 were used in 31 patients with advanced gynecological and genitourinary neoplasms. The DDP was given by 6 hours intravenous infusion with 2 liters of 5% Dextrose and 0.5 normal saline using Mannitol and/or furosemide diuresis. Courses were repeated every 21 to 28 days. Responses were seen in 7 of 8 patients with germinal cell neoplasms (5 complete, 2 partial) with a median duration of eight months. A partial response was obtained in 3 of 7 patients with bladder carcinoma with a median duration of three months. There were four partial responses obtained in 9 patients with ovarian carcinoma with a median duration of five months. Toxicities included nausea and vomiting in all 31 patients, nephrotoxicity (serum creatinine > 2 g/100 ml) in patients, tinnitus and/or high frequency hearing loss in 10 patients, and neurotoxicity (peripheral neuropathy, normal pressure hydrocephalus, papilledema) in 8 patients. Severe leukopenia (WBC < 2000/cu mm) and thrombocytopenia (< 100,000/cu mm) occurred in 25% and 45% of evaluable courses, respectively and necessitated dosage reduction in all and delay of therapy in some patients. Peak plasma Pt levels were 2.61 +/- .18 microgram/cc on day 1 and 3.52 +/- .39 microgram/cc on day 8 with a longer terminal half-life on day 8 (252 hours) compared to day 1 (156 hours). Peak plasma ADR levels ranged from .53 to 1.67 N moles/cc with an average terminal half-life of 22.8 hours. This agrees with values of ADR when given alone. This dose and schedule of DDP-ADR is active against advanced gynecological and genitourinary neoplasms, but the amount of toxicity seen indicates that modifications will have to be made.

[The pharmacokinetics of adriamycin and adriamycin-metabolites (author's transl)]

A sensitive reproducible, nondestructive method for the determination of adriamycin and its metabolites in plasma, leukocytes and tissues has been developed. Apolar substances as adriamycinone (adm-one) were extracted at pH 2 with chloroform, polar ones as adriamycin (adm) and adriamycinol (adm-ol) at pH 8.8 with chloroform: methanol, separated by thin-layer-chromatography and quantitated by fluorescence spectrophotometry. The plasma levels of adm-ol and adm-one were lower in all patients compared to those of adm. Further metabolites were found in the bile. Toxic effects were found in patients with prolonged half-lives in the elimination phase. A delayed elimination was observed in a patient with an elevation of the bilirubin level, but also in patients without overt liver disease. The pharmacokinetics of adm showed considerable inter- and intraindividual fluctuations.

Pharmacologic studies with radiolabeled N-trifluoroacetyladriamycin-14-valerate (AD 32). Comparison of total anthracycline fluorescence and radioactivity in mouse serum and urine

In connection with pharmacologic studies with AD 32, isotopically-labeled drug prepared from 1-[14C]-trifluoroacetic anhydride and adriamycin-14-valerate was used to determine murine serum and urine levels of radioactivity. Other studies, performed in parallel, measured serum and urinary total fluorescence. Serum fluorescence disappeared in a biphasic pattern, with an initial rapid rate of disappearance followed by a somewhat slower phase. For the first hour, serum radioactivity levels were not significantly different than those measured by fluorescence. After this, however, serum radioactivity decayed at a much slower rate than did fluorescence. Furthermore, a large fraction of the injected radioactivity was found excreted in the urine, whereas urine accounted for only a small fraction of the fluorescence. These results suggest the formation, in part, of a hitherto unrecognized nonfluorescent metabolite, most probably N-trifluoracetyldaunosamine.

Measurement of adriamycin (doxorubicin) and its metabolites in human plasma using reversed-phase high-performance liquid chromatography and fluorescence detection

We describe a method for measuring adriamycin and its major metabolite, adriamycinol, in plasma, using reversed-phase high-performance liquid chromatography and fluorescence detection. The lower limit of detection is approximately 1 ng/ml for both compounds; within-day coefficients of variation are 3.6% and 4.4% for adriamycin and adriamycinol, respectively. A slight modification of this procedure also allows measurement of aglycone metabolites.

Mathematical model for adriamycin (doxorubicin) pharmacokinetics

Adriamycin (doxorubicin), an active antineoplastic drug, is rapidly distributed across cell membranes and is concentrated within cells. Binding to protein and to tissue readily occurs. The drug is metabolized to both fluorescent and nonfluorescent compounds, the liver being the main organ of biotransformation and elimination. A multicompartment, open model that accounts for these processes has been derived. The model assumes an initial volume of distribution of 60% of body weight and includes two peripheral adriamycin compartments and a subsystem for adriamycinol, a major metabolite. Plasma and urine concentrations of adriamycin and adriamycinol were determined for four patients treated with adriamycin (60 mg/m2), and these concentrations were used to calculate rate constants for the model. Concentrations were measured by fluorescence assay after thin-layer chromatographic separation of parent compound and metabolites. Differential equations were solved by the SAAM computer program. Evaluation of adriamcinol pharmacokinetics suggests that the previously reported high concentrations of adriamycinol immediately after IV infusion of adriamycin are an artifact of the fluorescence method and that observed plasma concentrations of adriamycinol are the sum of adriamycinol concentrations and approximately 10% of the adriamycin concentrations. Corrected peak plasma concentrations of adriamycinol occur 2--12 h after infusion of adriamycin.

Adriamycin stimulates canine kidney (MDCK) cells to deacylate cellular lipids and to produce prostaglandins

Dog kidney (MDCK) cells treated with adriamycin (0.5 micrograms/ml) for 1 hr, produced from 2 to 7 times more prostaglandins E2 and F2alpha when measured in culture media 24, 48 and 72 hrs after the treatment. Indomethacin (ID50 less than 2 x 10(-8) M) and cycloheximide (0.5 micrograms/ml) inhibited this adriamycin-stimulated prostaglandin production. The aglycone of adriamycin (0.5 to 5.0 micrograms/ml) had little stimulating effect. Treatment of [3H]arachidonic acid-labeled MDCK cells with adriamycin (0.5 micrograms/ml) for 1 hr also stimulated deacylation of cellular lipids during subsequent incubation. Altered morphology of MDCK cells resulted from such treatment with adriamycin; indomethacin did not inhibit this change, but cycloheximide did.

Liquid chromatographic determination of daunorubicin and daunorubicinol in plasma from leukemic patients

A method is given for the determination of daunorubicin and its main metabolite, daunorubicinol, in plasma from leukemic patients after administration of daunorubicin as the free drug or as a complex with DNA. Daunorubicin and daunorubicinol are extracted from 2 ml of plasma (pH 8.1) using a mixture of chloroform and 1-heptanol (9:1). After re-extraction into phosphoric acid (0.1 M), the separation is performed as reversed phase liquid chromatography on a LiChrosorb RP-2 (5 micrometer) column with a mobile phase of acetonitrile-water, acidified with phosphoric acid. The precision, by quantitation with a photometric detector, was better than 2% within the range 20 ng/ml to 200 ng/ml. Some determinations of plasma levels of daunorubicin and daunorubicinol are presented.