Preparation and in vitro evaluation of magnetic microsphere-methotrexate conjugate drug delivery systems.

Magnetic microsphere-methoxtrexate (MM-MTX) conjugates prepared by several different methods were analyzed for their suitability for in vivo use. MM-MTX were prepared by the following methods: (A) reaction of MTX with poly(ethylene glycol) 1500 (PEG) to form a poly(ethylene glycol)-methotrexate conjugate (PEGMTX) which was then added to a ferrous/ferric ion salt solution to give MM-MTX I; (B) reaction of ferrous/ferric ion salts with PEG to give a ferromagnetic polymer complex which was then coupled with MTX to give MM-MTX II; (C) MM-MTX IIIA were prepared by reacting MTX with amino-terminated magnetic microspheres, commercially available, in the presence of 1-ethyl-3,3-bis(methylamino)propylcarbodiimide (EDCI); (D) reaction of aminohexanol with di-tert-butyl dicarbonate to form an [N-(tert-butoxycarbonyl)amino]hexanol (t-Boc-AH), which was then coupled with MTX in the presence of 1,3-dicyclohexylcarbodiimide and 4-pyrrolidinopyridine to give a t-Boc-AH-MTX conjugate, which was then saturated with hydrogen chloride to give an aminohexanol-methotrexate (AH-MTX) conjugate. MM-MTX IIIB were then prepared by reacting AH-MTX with carboxyl-terminated magnetic microspheres, commercially available, in the presence of EDCI and 4-(dimethylamino)pyridine. The identity of MTX conjugates was confirmed using ultraviolet, infrared, and nuclear magnetic resonance spectroscopy. Drug content of the magnetic microsphere-methotrexate conjugates as determined by HPLC was 0.45% (w/w), 4.0% (w/w), and 6.3% (w/w) MTX for MM-MTX I, MM-MTX II, and MM-MTX IIIB, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

HPLC separation of pentazocine enantiomers in serum using an ovomucoid chiral stationary phase.

A stereospecific HPLC method was developed for the analysis of (-) and (+) pentazocine in human serum. Each enantiomer and the internal standard nalophine were isolated from serum using a liquid-liquid extraction procedure. Recoveries of 99.05 +/- 5.37 and 97.42 +/- 2.78% were obtained for (-) and (+) pentazocine, respectively. Resolution of the enantiomers was obtained by using an ovomucoid chiral stationary phase with a mobile phase of methanol:acetonitrile: 10 mM phosphate buffer, pH 5.8 (20:5.3:74.7 v/v/v). A resolution (Rs) value of 1.80 was obtained for the pentazocine enantiomers. Linear calibration curves were obtained in the 10-100 ng/mL range for each enantiomer in serum. The detection limit based on a signal-to-noise ratio of 3 was 5 ng/mL for each enantiomer in serum using fluorescence detection with excitation at 275 nm and emission set at 335 nm. The lowest quantifiable level was found to be 10 ng for each enantiomer. Precision and accuracy of the method were in the 3.8-4.8% and 1.3-4.2% ranges, respectively.

Identification of metoclopramide metabolites in the urine of cattle by gas chromatography-mass spectrometry and high-performance liquid chromatography-photodiode array detection.

The urinary metabolites of metoclopramide (4-amino-5-chloro-N-[2-diethylaminoethyl]-2-methoxybenzamide) were identified in cows. The drug was administered intravenously, voided urine was collected, and individual urine extracts were analysed by gas chromatography-mass spectrometry and high-performance liquid chromatography-photodiode array detection. The parent compound and one major metabolite (4-amino-5-chloro-N-[2-(ethylamino)ethyl]-2-methoxybenzamide) were common to all individuals. In addition to the parent and major metabolite, a second, minor metabolite was identified in two cows as 4-amino-5-chloro-N-[2-(diethylamino)ethyl]-2-hydroxybenzamide. The identity of the minor metabolite was confirmed by comparison with a standard synthesized by a new method. Metabolite identification and characterization in food animal species allows the design of safety and environmental impact studies and relative metabolite ratios between dose treatment groups.

Synthesis of previously inaccessible quinazolines and 1,4-benzodiazepines as potential anticonvulsants.

A series of 4,6,7,8- tetrasubstituted 3,4- dihydroquinazolines , quinazolines, quinazolin -2-ones, 1,2,3,4- tetrahydroquinazolin -2-ones, and 5,7,8,9- tetrasubstituted 1,4-benzodiazepines have been synthesized by utilizing the Diels -Alder reaction between furan o-amino nitriles and various alkyl or aryl vinyl ketone dienophiles to obtain the anthranilic acid precursors. All of the newly synthesized target compounds were evaluated in mice for anticonvulsant activity. Pro- and anticonvulsant action was quantified by the timed intravenous pentylenetetrazol seizure threshold method. Selected compounds were also evaluated for benzodiazepine receptor binding properties and in vivo antagonist potential. Although the compounds lack potency, the data suggest that previously inaccessible substituted analogues may be useful to segregate the proconvulsant , anticonvulsant, and antagonist actions of benzodiazepines and quinazolines.

Synthesis of 3,4-dihydro-4-oxoquinazoline derivatives as potential anticonvulsants.

Twenty-three substituted 3,4-dihydro-4-oxoquinazolines or 3,4-dihydro-4-oxoazaquinazolines have been synthesized utilizing 2-amino-3-cyano-4,5-dimethylfuran and methyl acrylate as precursors for synthesis of the required substituted anthranilates. Six additional azaquinazolones were synthesized from 2-aminonicotinic or 3-aminopicolinic acid for comparison studies. All compounds were evaluated in mice with the maximal electroshock (MES) seizure and pentylenetetrazol (sc Met) seizure threshold tests for potential anticonvulsant activity and in the rotorod test to evaluate neurotoxicity. Nine of the twenty-nine compounds in the series demonstrated anticonvulsant action. The azaquinazolones were found to possess the most significant activity.

Synthesis of 2-substituted primaquine analogues as potential antimalarials.

A series of 2-substituted primaquine analogues has been synthesized and evaluated against Plasmodium berghei in the mouse and Leishmania donovani in the hamster. Three members (3a,d,e) of the series were evaluated against Plasmodium cynomolgi in the rhesus monkey. One analogue (3d) was evaluated against Trypanosoma rhodesiense in the mouse, and two (3b,e) were evaluated against Schistosoma mansoni in the mouse. Several analogues possessed significant activity against P. berghei (3e,f) and L. donovani (3a,e).

Pyrrole, furan, and thiophene oxamates as potential antiallergy agents.

Nine heterocyclic oxamic acid derivatives were synthesized and tested in the rat passive cutaneous anaphylactic assay as potential antiallergy agents. Some compounds also were tested for their effects on cholesterol-lipoprotein levels and for diuretic, antidiabetic, and antifertility activities in rats.

Synthesis of 2-benzyloxy and 2-benzylthio analogues of primaquine as potential antimalarials.

A series of 2-benzyloxy and 2-benzylthio analogues of primaquine has been synthesized and evaluated against Plasmodium berghei in the mouse and Plasmodium cynomolgi in the rhesus monkey. 8-Aminoquinoline toxicity, as measured in the Rane mouse screen, was reduced, and these compounds showed significant blood schizonticidal antimalarial activity in mice. In monkeys, significant tissue-schizonticidal activity was observed.

5-Aryloxy-6-methoxy-8-aminoquinolines as potential prophylactic antimalarials.

5-(p-Anisyloxy)-6-methoxy-8-(5-isopropylaminopentylamino)quinoline was resynthesized for evaluation in the Plasmodium berghei and monkey prophylactic (Plasmodium cynomolgi) tests. A new primary amine, three secondary amines, and one structurally modified side-chain analog of the 5-aryloxy series were also prepared. None of these compounds showed significant antimalarial or prophylactic activity.

New synthesis of substituted pyrrolo[1,2-alpha][1,3]diazepine and its pharmacological activity.

A facile route for the synthesis of the substituted pyrrolo[1,2-alpha][1,3]diazepine nucleus from readily available starting material is reported. The compound was tested for antimalarial activity in mice, antineoplastic activity in mice, acute hypotensive activity in rats and dogs, effect on cholesterol-lipoprotein levels in rats, anti-inflammatory activity in rats, antiviral activity in mice, CNS depressant or stimulant activity in mice, diuretic activity in fasted rats, and antidiabetic activity in rats. Hypotensive activity of relatively short duration was observed in rats. The compound lacked positive pharmacological activity in the remaining tests.

Synthesis of thieno[2,3-b]azepin-4-ones as potential antineoplastic agents.

In view of the antitumor activity reported for 7,8-dimethylbenzo[b]azepine-2,5-dione, new isosteric thieno[2,3-b]-azepin-4-ones have been prepared by a Dieckmann ring closure reaction. Substituted 2-amino-3-carbethoxythiophenes were tosylated, or benzoylated, and the corresponding sodium salt was alkylated with ethyl 4-bromobutyrate. The resulting product was cyclized in the presence of sodium hydride, and the azepinones were detosylated with 40% sulfuric acid-acetic acid solution. Preliminary biological data do not indicate any siginificant antineoplastic activity.