Intravenous and intramuscular pharmacokinetics of recombinant leukocyte A interferon.

Interferon is currently being evaluated for the treatment of disseminated cancer and viral diseases. Alpha interferons have shown to be effective in the treatment of a number of malignancies. Recombinant leukocyte A interferon (rIFN-alpha A) is an alpha interferon produced by recombinant DNA techniques. A kinetic evaluation of rIFN-alpha A following intravenous and intramuscular administration has not been adequately defined. The present study was designed to evaluate the kinetics of rIFN-alpha A following intravenous and intramuscular administration of 3, 9 or 18 X 10(6) units to patients with disseminated cancer. A preliminary report of this study was presented at the meeting of the American Society for Clinical Pharmacology and Therapeutics in San Diego, March 1983 (1).

Pharmacokinetics of recombinant leukocyte A interferon following various routes and modes of administration to the dog.

The pharmacokinetics of recombinant leukocyte A interferon (rIFN-alpha A) were studied following intravenous (i.v.) bolus, 60 min (i.v. inf.) infusion, intramuscular (i.m.), subcutaneous (s.c.), and oral (p.o.) administrations to 15 male beagle dogs. Each animal received at least one 3 X 10(6) units/kg dose of rIFN-alpha A by one of the five routes and/or modes of administration. Blood samples were collected and the serum was separated and analyzed for rIFN-alpha A concentrations by an enzyme immunoassay, ELISA. There were no measurable rIFN-alpha A concentrations (less than 0.020 ng/ml) following oral administration. In general serum rIFN-alpha A concentrations exceeded 100 ng/ml following i.v. bolus and infusion doses then declined rapidly in a biphasic manner. The volume of distribution at steady state Vdss ranged from 0.14 to 0.21 liters/kg after i.v. infusion. Total body serum clearance (ClB) ranged from 14.6 to 23.9 ml/min, which is about 50% the estimated inulin clearance in dogs. The harmonic mean elimination half-lives ranged from 4.5 to 9.5 h. A prolonged absorption profile was seen following i.m. and s.c. administrations and the systemic bioavailability for both routes was 42% when compared with the i.v. infusion. These appear to be the first pharmacokinetic profiles of rIFN-alpha A reported in the dog.

Improvement in clinical condition and thymus morphologic features associated with growth hormone treatment of immunodeficient dwarf dogs.

Immunodeficient dwarfism in Weimaraner dogs was characterized by failure to grow, emaciation, growth hormone (GH) deficiency, decreased lymphocyte blastogenic responsiveness to mitogens, lack of thymus cortex, and recurrent infections usually resulting in death. Affected pups did not respond to conventional supportive therapy, but did respond to treatment with thymosin fraction 5. Response to therapy with bovine GH was monitored by clinical observation, histopathologic examination of thymic biopsy material, lymphocyte blastogenic responsiveness to nonspecific mitogens, and radioimmunoassay of thymosin alpha 1 concentration in the serum. Growth hormone therapy (0.1 mg/kg of body weight/dose, 14 doses) during a 1-month period in 2 immunodeficient dwarf pups resulted in clinical improvement and a marked increase in the thickness and cellularity of the cortex of the thymus. Immunodeficient dwarf pups were not deficient in serum thymosin alpha 1 before GH therapy. Growth hormone therapy was not associated with a consistent increase in serum thymosin alpha 1 concentration or lymphocyte blastogenic responsiveness to mitogens.

Interferon kinetics and adverse reactions after intravenous, intramuscular, and subcutaneous injection.

Three groups of six subjects each received a single 36 X 10(6) U dose of recombinant leukocyte A interferon (rIFN-alpha A) as a 40-min infusion, an intramuscular injection, or a subcutaneous injection. Blood samples were collected at specific times after dosing for analysis of rIFN-alpha A serum concentrations by an enzyme immunoassay method, ELISA. The rIFN-alpha A was rapidly distributed and moderately eliminated (t 1/2 = 5.1 hr) after intravenous infusion. The maximum concentrations at the end of intravenous infusion were tenfold the maximum concentrations after intramuscular and subcutaneous injections. Renal tubular secretion or extrarenal elimination was suggested by clearance values of 1.8 times the glomerular filtration rate. After intramuscular and subcutaneous injection, rIFN-alpha A was absorbed slowly (time to reach maximum concentration ranged from 4 to 8 hr), which resulted in prolonged serum concentrations. Estimated bioavailability was more than 80% for both intramuscular and subcutaneous injection shares qualitatively the same adverse reactions, the reactions differ in severity and duration. The adverse effects appear to be related to route of administration of herpes labialis were also noted. There were no significant clinical laboratory abnormalities of medical concern. Although rIFN-alpha A injected by intravenous infusion or intramuscular or subcutaneous injection shares qualitatively the same adverse reactions, the reactions differ in severity and duration. The adverse effects appear to be related to route of administration.

Pharmacokinetics of recombinant alpha A interferon following I.V. infusion and bolus, I.M., and P.O. administrations to African green monkeys.

The pharmacokinetics of recombinant alpha A interferon (rIFN-alpha A) were studied following an intravenous (iv) bolus, 60 min infusion, intramuscular (im), and oral administrations to four African Green monkeys. Each monkey received 3 X 10(6) units/kg of rIFN-alpha A parenterally and 6 X 10(6) units/kg orally. Blood samples were collected and the serum was separated and analyzed for rIFN-alpha A concentrations by an enzyme immunoassay, ELISA. No significant changes in clinical chemistry values resulted from rIFN-alpha A administration. There were no measurable rIFN-alpha A concentrations (less than 20 pg/ml) following oral administration. Serum rIFN-alpha A concentrations declined rapidly in a biphasic manner following iv bolus and infusion doses and were described by a single pharmacokinetic model. The volume of distribution at steady state (Vdss) ranged from 0.034 to 0.31 l/kg after iv infusion. Total clearance ranged from 4.5 to 19 ml/min, which is about 75% the estimated inulin clearance in monkeys, suggesting glomerular filtration without reabsorption. The elimination half-life ranged from 1.8 to 4.8 h. A prolonged absorption profile was seen following im administration and the systemic bioavailability was 93% when compared with intravenous infusion. The overall disposition of rIFN-alpha A is comparable to the disposition of other interferons in both animals and humans. The monkey appears to be a suitable pharmacokinetic model for the testing of rIFN-alpha A and could be useful in conjunction with a viral efficacy model.

Effects of smoking and age on serum levels of immune reactive proteins.

In patients with head and neck squamous carcinoma, prior studies demonstrating correlations among levels of certain immunosuppressive acute phase proteins, tumor extent, and immune reactivity suggest that these protein levels may be useful parameters for assessing tumor status and clinical course after treatment. Because of the consistent association of chronic smoking with the development of cancers of the head and neck, the effects of smoking and age on levels of acute phase proteins (alpha 1-antitrypsin, haptoglobin, alpha 1-acid glycoprotein) and other immune reactive proteins (alpha 2HS-glycoprotein, prealbumin) were determined in smoking and nonsmoking normal subjects. In smokers, levels of alpha 1-antitrypsin were uniquely and significantly elevated and were not related to smoking extent or age. Levels of haptoglobin increased with smoking extent and age. In comparisons of age- and sex-matched smokers and nonsmokers, levels of alpha 1-acid glycoprotein increased with age among both groups. The demonstration of correlations of levels of immunosuppressive acute phase proteins with smoking extent and age among normal subjects suggests that changes in the levels of these proteins may be related etiologically to the association of smoking and age with the development of head and neck cancers.

Serum glycoproteins in cancer patients: first report of correlations with in vitro and in vivo parameters of cellular immunity.

Serum levels of proteins previously shown to be elevated [acute-phase proteins (APP)-haptoglobin, alpha 1-acid glycoprotein, alpha 1-antitrypsin] or depressed (alpha 2 HS-glycoprotein, prealbumin, albumin) in cancer patients were correlated with tumor extent, in vitro lymphocyte reactivity (LR) to phytohemagglutinin (PHA), and quantitative delayed hypersensivity (DH) to dinitrochlorobenzene (DNCB) in 147 preoperative patients with operable solid malignancies either confined to the primary site or with regional spread only. Compared to 58 normal controls, levels of the APP were significantly elevated, alpha 2 HS-glycoprotein and prealbumin depressed, and albumin levels unchanged in patients with either local or regional tumors. In patients with normal DH to DNCB, the APP were higher and prealbumin was lower than in controls; in patients with impaired DH to DNCB, haptoglobin and alpha 1-acid glycoprotein were higher and alpha 2 HS-glycoprotein and prealbumin lower than in patients with normal DH to DNCB. Albumin levels did not differ from normals in any of the groups. Serum protein levels appeared to be more related to the immune status of the patient than to tumor extent. The levels of the three APP correlated directly with each other but inversely with alpha 2 HS-glycoprotein and prealbumin; levels of alpha 2 HS-glycoprotein and prealbumin correlated directly with each other. Levels of haptoglobin and alpha 1-acid glycoprotein correlated inversely with LR to PHA; however, levels of alpha 2 HS-glycoprotein correlated directly with LR to PHA, and uniquely the levels of alpha 2 HS-glycoprotein and LR to PHA both showed similar changes for each of the four quantitative levels of DH to DNCB measured in the cancer patients. The data show that the proteins studied, except for albumin, correlate inversely (APP) or directly (alpha 2 HS-glycoprotein and prealbumin) with in vitro and in vivo parameters of cellular immunity. The results provide a rationale for attempts to improve depressed cellular immunity by lowering circulating levels of APP, as is being attempted in ongoing trials using plasmapheresis, and assessing the effect of exogenous alpha 2 HS-glycoprotein or prealbumin in patients with low levels of these glycoproteins and depressed cellular immunity. The correlations between serum glycoprotein levels and in vitro and in vivo parameters of cellular immunity lend rationale to investigations of the interactions of serum glycoproteins and blood cells having immunologic function that determine the level of cellular immunity expressed in vivo.

Plasma activity of pyruvate kinase and glutamic oxalacetic transaminase as indices of myopathy in the vitamin E deficient rat.

Weanling rats were fed vitamin E deficient diets for 6 to 15 weeks and then given vitamin E orally for 4 days. Plasma obtained 1 day after the last dose was assayed for glutamic oxalacetic transaminase (GOT) and pyruvate kinase activity (PK). Administration of vitamin E resulted in reduction in activity of both enzymes. Plasma levels of alkaline phosphatase, lactic dehydrogenase, and bilirubin were unaffected by vitamin E and there was no histological evidence of liver degeneration. The number of phagocytized muscle fibers was greatly reduced by vitamin E treatment, but a substantial number of necrotic fibers were still present. With more prolonged (8 days) treatment, plasma PK and GOT levels were reduced to levels found in plasma of vitamin E replete animals and few degenerated muscle fibers could be observed. It was concluded that resolution of the necrotizing myopathy in vitamin E deficient rats is a rapid process and that the decreased activity of PK and GOT in plasma is a sensitive indicator of the resolution process. The decrease in plasma enzyme levels is an easily quantitated and reproducible biological response to vitamin E administration. Thus, this approach provides a basis for a sensitive and accurate bioassay for vitamin E activity.

An improved method for determining total urinary phenol.

A simple and easily manipulated method is described for th- determination of total urinary phenol. This modification of earlier procedures incorporates the enzymatic hydrolysis of conjugated phenol, extraction of the hydrolysis products into isopropyl ether and final quantitation by gas-liquid chromatography-flame ionization detection. The method employs benzyl alcohol as internal standard.

DOPA stability in plasma and plasma extracts.

Unextracted heparinized plasma samples containing L-DOPA can be refrigerated or frozen with negligible losses in drug for at least two weeks. This stability of L-DOPA in the sample obviates difficulties in collection and processing of plasma samples within clinical settings which may be remote from the analytical laboratory facilities.

The stability and reliability of radioimmunoassays for clonazepam, diphenylhydantoin and phenobarbital in blood, serum or plasma.

The stability of Clonazepam, Diphenylhydantoin and Phenobarbital has been established in plasma and whole blood samples under a variety of storage conditions. Radioimmunoassay techniques for each of these anticonvulsants is not effected by the presence of the other anticonvulsants. Abnormal states such as icterus, hemolysis and lipemia were studied for their effects on the radioimmunoassay of these anticonvulsants. All the anticonvulsants can be stored at 37 degrees C with appropriate preservation for at least one week.

Some aspects of sodium nitroprusside reaction with human erythrocytes.

Sodium nitroprusside is an excellent agent for lowering blood pressure in hypertensive emergencies, for producing controlled hypotension during anesthesia, and for treating acute myocardial infarction and chronic heart failure. Toxic effects of this drug have been reported and above-normal cyanide and thiocyanate concentrations have been observed in the blood of a small proportion of subjects receiving nitroprusside. Nitrite, syanide, and thiocyanate are major decomposition products of nitroprusside, resulting from an in vitro reaction with human blood. On the basis of the conversion mechanism, we suggest that, in the cyanide/thiocyanate cycle, only cyanide is directly responsible for any acute toxicity attributed to sodium nitroprusside. In this work, the extent of cyanide production by erythrocytes in vitro was studied. The rate of detoxification of cyanide by human liver in vitro was experimentally determined and data from a search for a possible inhibitor of the nitroprusside/hemoglobin reaction are presented. Also, the possible mechanism of the nitroprusside/hemoglobin reaction is discussed.

Lack of antiscorbutic activity of ascorbate 2-sulfate in the rhesus monkey.

Oral administration of 10 mg per kilogram of body weight of ascorbic acid (AA) completely prevented development of scurvy in juvenile rhesus monkey (Mucaca mulata) fed an AA-free liquid diet. The same dose cured scurvy when injected intramuscularly. An equimolar dose of ascorbic acid 2-sulfate (AA-2-S) did not prevent or cure scurvy. Neither AA nor AA-2-S altered serum cholesterol. AA but not AA-2-S reduced serum triglyceride. A case of scurvy in an AA-2-S treated monkey is described in detail.