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At least 19 recordsLinked to original sources
PubMed1984

Formulation of a stable vidarabine phosphate injection.

An injection fluid with vidarabine phosphate (37.5 mg/ml, pH 7.4) was formulated. After steam sterilization for 20 min at 120 degrees C a 6.1% degradation was observed. No significant (p greater than 0.05) degradation could be observed after heating in steam for 30 min at 100 degrees C and after storage for four months at 4 degrees C. From the results of an investigation of the degradation rate at elevated temperatures a negligible loss of content after a three years' storage period at 4 degrees C could be predicted.

Chromatography, High Pressure Liquid↗
PubMed1987

Adenine arabinoside monophosphate (vidarabine phosphate) in combination with human leukocyte interferon in the treatment of chronic hepatitis B. A randomized, double-blinded, placebo-controlled trial.

STUDY OBJECTIVE: To determine the efficacy of adenine arabinoside monophosphate (Ara-AMP vidarabine phosphate) with or without human leukocyte interferon in chronic hepatitis B. STUDY DESIGN: Randomized, double-blinded, placebo-controlled trial with 6-month treatment and an 18-month follow-up. SETTING: Referral-based liver-disease clinics at three university medical centers. PATIENTS: Twenty-five patients with chronic active hepatitis or cirrhosis and 39 with chronic persistent hepatitis. INTERVENTIONS: Thirteen patients received intramuscular Ara-AMP, 2.5 mg/kg body weight, twice daily, alternated monthly for 6 months with subcutaneous human leukocyte interferon, 5 million units, twice daily. Painful paresthesia of the legs necessitated dosage reduction and early discontinuation of enrollment. Twenty-four patients received intramuscular Ara-AMP, 2.5 mg/kg, twice daily, alternated monthly for 6 months with a matching placebo given subcutaneously twice daily. Twenty-seven patients received placebo by intramuscular and subcutaneous injections twice daily for 6 months. MEASUREMENTS AND MAIN RESULTS: Of the 64 patients, 95% had symptomatic and virologic data available and 64% had biopsies at 12 months; at 24 months, 77% had data available and 56% had repeat biopsies. The highest dropout rate was seen in the group receiving Ara-AMP. The group receiving the placebo was less symptomatic (Karnofsky score of 96% compared with 91% in the group receiving Ara-AMP/placebo and 92% in the group receiving Ara-AMP/human leukocyte interferon, p = 0.02) at 12 but not at 24 months. Loss of DNA polymerase, the hepatitis B e antigen, and the serum hepatitis B virus DNA was similar in all three groups. Histologically, erosion of the limiting plate and lobular activity favored Ara-AMP at 12 but not at 24 months and these differences did not result in differences in the histologic diagnosis. CONCLUSION: These results do not support the use of Ara-AMP and human leukocyte interferon in chronic persistent or chronic active hepatitis B.

Adult↗
PubMed1986

Recent advances in antiviral therapy.

Virus replication is described, and the clinical trials and indications for amantadine, rimantadine, vidarabine, vidarabine phosphate, acyclovir, ribavirin, and other promising antiviral agents are reviewed. Amantadine and rimantadine are useful for the treatment and prophylaxis of viral influenza A infections. Vidarabine is a second-line agent and is effective for the treatment of herpes simplex encephalitis, neonatal herpes simplex types 1 and 2, and varicella-zoster infections. Vidarabine phosphate (also known as vidarabine monophosphate) has a similar spectrum of activity and can be administered in smaller volumes than vidarabine. Acyclovir has demonstrated clinical efficacy for chickenpox, shingles (herpes zoster), genital herpes, and other herpes simplex infections. Acyclovir is also useful for the suppression of herpes infections. Systemically administered ribavirin is indicated for the treatment of Lassa fever. Aerosol ribavirin is effective for the treatment of respiratory syncytial virus pneumonia in children and infants and influenza A infections in adults. Only acyclovir, amantadine, ribavirin, and vidarabine are used in clinical practice. Vidarabine phosphate and investigational agents such as rimantadine, ganciclovir (DHPG, BW B759U), phosphonoformate, and bromovinyl-deoxyuridine (BVDU) need further investigation.

Antiviral Agents↗
PubMed1988

Topically applied vidarabine sodium phosphate in genital herpes infection.

One hundred and thirty-four patients with recurrences of genital herpes were randomized in a double-blind trial to receive self-applied topical therapy with either vidarabine sodium phosphate in an aqueous gel or placebo gel. No significant differences were noted between the two groups in the duration of viral shedding, in the time to healing of the treated recurrence, in the interval between recurrences, or in the number of recurrences.

Administration, Topical↗
PubMed1992

Effect of six virustatic nucleoside analogues on the development of fetal rat thymus in organ culture.

The effects of the virustatic agents zidovudine (azidothymidine, AZT) 2'3'-dideoxycytidine (ddC), 2'3'-dideoxyinosine (ddI), acyclovir (ACV), ganciclovir (GCV), and vidarabine phosphate (VP) on the in vitro development of thymic lobes of 17-day-old rat fetuses were tested in an organ culture system. The virustatics were added to the medium for a culture period of 7 days. All nucleoside analogues inhibited the proliferation and differentiation of lymphatic cells. However, differences were observable with respect to the potency of the six drugs to interfere with thymic development. Compared to untreated controls, reduction in the number of thymocytes was significant at concentrations of 30 microM AZT and ddI. In the case of ACV, GCV, VP, and ddC concentrations as low as 10 microM were sufficient to cause a significant reduction, ddC being the most potent derivate. Increasing concentrations of the nucleoside analogues led to a dose-dependent further inhibition of cell proliferation. At a concentration of 30 microM flow cytometry revealed a decrease in the relative number of double positive CD4+ CD8+ and single positive CD4+ CD8- cells but an increase in the relative number of CD4-CD8+ cells. At the same concentration the expression of the CD5 antigen was reduced by the antimetabolites, indicating that maturation of the thymocytes was inhibited. Distribution of the forward light scatter, a cell size-related parameter, showed that the formation of small thymocytes was reduced by the nucleoside analogues. Light and electron microscopic investigations indicated cytotoxic effects of the drugs on the thymocytes, whereas the epithelium was only slightly affected.

Animals↗
PubMed1991

In vitro and in vivo studies on the prenatal toxicity of five virustatic nucleoside analogues in comparison to aciclovir.

Several virustatic agents are known to be teratogenic in laboratory animals. Since routinely performed in vivo studies do not always offer the best conditions to detect the teratogenic potential of a drug, we used a combined in vivo/in vitro approach for comparative studies on the prenatal toxicity of five nucleoside analogues. Rat embryos were exposed for 48 h to various concentrations of vidarabine-phosphate (VAP), ganciclovir (GCV), 2',3'-dideoxyadenosine (ddA), 2',3'-dideoxycytidine (ddC) and zidovudine (= azidothymidine, AZT) in a whole-embryo culture system. The steepness of the concentration-response curves as well as the induced abnormality pattern (head, neural tube, shape) were similar for these compounds. However, a wide range in embryotoxic potency was observed: VAP was the most potent compound (100% abnormal embryos at 25 microM) in this in vitro system, while AZT showed the lowest potency to interfere with normal embryonic development (40% abnormal embryos at 3000 microM). In addition to these experiments we treated rats on day 10 of gestation with three s.c. injections (8 a.m.; 12 a.m.; 4 p.m.) of 200 mg of each drug/kg body wt. The embryos were evaluated on day 11.5 of gestation, i.e. at a time of development corresponding to the developmental stage at the end of the whole-embryo culture. The same criteria were used as during the in vitro studies for the evaluation of these in vivo exposed embryos. With VAP and GCV we obtained similar results with both exposure routes (in vitro and in vivo), while no abnormalities were detectable with the other compounds after exposure in utero.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Drug-Induced↗
PubMed2000

[Contact dermatitis to topical antiviral drugs].

BACKGROUND: Topical antiviral drugs are frequently used. Repeated applications on a skin injured by the viral infection can lead to irritating dermatitis or contact eczema. This secondary effect is often unrecognized because imputed to an increase of the initial dermatosis. CASES REPORTS: Case 1 - A 58 year-old woman had an eczema around the mouth after the use of Zovirax(R) cream (acyclovir). The patch test with this cream was positive (++ at 96 h) but the detail of all the constituents was negative. Case 2 - A 39 year-old woman had an eczema surrounding the mouth after each use of Zovirax(R) cream and Cuterpes(R) (ibacitabin). The patch tests were doubtful for Zovirax(R) cream, positive for Cuterpes(R) (++ at 96 h) and ibacitabin 1 p. 100 and 10 p. 100 in petrolatum (++ at 96 h). Case 3 - A 58 year-old man had an acute eczema of the face after the use of Zovirax(R) cream and Vira-MP(R) (vidarabin phosphate). The patch tests were positive for the both antiviral topical drugs but negative for each one of their constituents. DISCUSSION: Contact dermatitis to antiviral topical drugs are rare, due to active molecule or its excipients. The propyleneglycol, component found in the three antiviral drugs, can induce irritation or allergy. In the most of cases, like in our case number 1 and 3, the patch tests with each constituents of the topical drugs were negative, we conclude to a compound allergy.

Administration, Topical↗
PubMed1990

9-Beta-D-arabinofuranosyladenine 5'-monophosphate (araAMP) is converted directly to its antivirally active 5'-triphosphate form by 5-phosphoribosyl-1-pyrophosphate (PRPP) synthetase.

The antiherpetic agent 9-beta-D-arabinofuranosyladenine (araA) needs to be phosphorylated to its 5'-triphosphate to be effective as an inhibitor of herpes simplex virus replication. Adenosine kinase and deoxycytidine kinase are assumed to convert araA to its 5'-monophosphate. We now found that araAMP is converted to its 5'-triphosphate through a direct pyrophosphate transfer from 5-phosphoribosyl-1-pyrophosphate (PRPP) by PRPP synthetase. The efficiency of phosphorylation of araAMP to araATP is about 5% of that of AMP, as estimated from their Vmax/Km ratios for PRPP synthetase. AraATP is converted to araAMP by PRPP synthetase at a 4-fold higher Km but similar Vmax as ATP.

Kinetics↗
PubMed1983

Inhibition of salvage pathway enzymes by adenine arabinoside 5'-monophosphate (ara-AMP).

The effect of 9-beta-arabinofuranosyladenine 5'-monophosphate (ara-AMP) on the purine salvage pathway has been studied. On a dose-dependent basis ara-AMP inhibits the incorporation of adenine-8-14C into nucleotides in intact erythrocytes. The partially purified enzymes of the purine salvage pathway, the adenine phosphoribosyltransferase and the 5'-phosphoribosyl-1-pyrophosphate (PP-ribose-P) synthetase, but not the hypoxanthine-guanine phosphoribosyltransferase, are inhibited by ara-AMP in a non-competitive manner. The possible adverse drug interactions which might occur by the simultaneous use of ara-AMP and other antimetabolites are discussed.

Adenine↗
PubMed2002

Corticosteroid responsive fludarabine pulmonary toxicity.

Fludarabine monophosphate is a purine nucleoside antimetabolite with efficacy in the treatment of lymphoproliferative disorders and chronic lymphocytic leukemia. It is the 2-fluoro, 5' phosphate derivative of 9-beta-D-arabinofuranosyl adenine (ara-A, vidarabine) and the mechanism of action is through inhibition of DNA synthesis and the cytolytic effects through the induction of endonuclease-independent apoptosis.

Antimetabolites, Antineoplastic↗
PubMed1992

1-beta-D-arabinofuranosylcytosine-diphosphate-choline is formed by the reversal of cholinephosphotransferase and not via cytidylyltransferase.

In an effort to identify the pathway leading to the formation of 1-beta-D-arabinofuranosylcytosine-diphosphate (ara-CDP)-choline from 1-beta-D-arabinofuranosylcytosine (ara-C) treatment of cultured cells, as well as of cells obtained from leukemia patients, we probed the enzymatic steps involved in the CDP-choline pathway for phosphatidylcholine biosynthesis. Ara-C-triphosphate was not a substrate for CTP:phosphocholine cytidylyltransferase activity under the conditions employed, whereas CTP and dCTP were utilized to form CDP-choline and dCDP-choline, respectively. When presented together, ara-C-triphosphate and CTP inhibited the enzymatic conversion of CTP to CDP-choline in the presence of phosphocholine, with a Ki of 6 mM. Since CTP:phosphocholine cytidylyltransferase did not appear to be responsible for the increased levels of ara-CDP-choline, we next studied the other enzyme in the pathway for phosphatidylcholine synthesis that could form ara-CDP-choline, CDP-choline:1,2-diacylglycerol cholinephosphotransferase. CDP-choline:1,2-diacylglycerol cholinephosphotransferase activity present in microsomes isolated from L5178Y murine leukemia cells exhibited a reversal of its normal catalytic activity, using CMP and 1-beta-D-arabinofuranosylcytosine-monophosphate (ara-CMP) along with phosphatidylcholine to produce either CDP-choline or ara-CDP-choline, plus diradylglycerol. The Vmax and Km values for CMP were 0.78 +/- 0.04 nmol/min/mg and 340 +/- 20 microM, respectively, whereas the Vmax and Km for ara-CMP were 0.22 +/- 0.06 nmol/min/mg and 1410 +/- 540 microM, respectively. A Ki value of 3 mM was obtained for ara-CMP under the cell-free assay conditions used. These results indicate that ara-CDP-choline most likely arises from a reversal of the CDP-choline:1,2-diacylglycerol cholinephosphotransferase utilizing ara-CMP, rather than from the catalysis of ara-C-triphosphate plus phosphocholine to ara-CDP-choline by CTP:phosphocholine cytidylyltransferase. It is speculated that this mechanism may explain, in part, the rapid cellular lysis observed with high dose ara-C therapy.

Animals↗