Study of Immobilization by Esteric Bond of 2-(m-Nitrophenyl)-4-(ОІ- Carboxymethyl)-О”2-Oxazolinone-5 on Gellan

The paper studies the coupling reaction, through ester-type covalent bonds, of an oxazolone derived from the N-(m-nitrobenzoyl)-L-asparagic acid, on gellan (a polysaccharide of microbian synthesis), in conditions of activation with dicyclohexyl carbodiimide. Based on a centered, rotatory, composed, second order experimental program, the regression equation describing the dependence of the amount of active principle, chemically bounded to the support, on the reaction’s  parameters (support/active principle ratio, active principle/activator ratio, duration) is obtained. One may observe that the efficiency of the coupling reaction is maximum when employing the parameters’ highest values, over the variation domain established. The coupling product has been characterized through elemental analysis and IR spectroscopy. For the establishment  of the capacity of the active principle’s controlled release by the polymer-active principle system thus obtained, drug’s release kinetics from the polysaccharidic support is studied in conditions of basic hydrolysis. The oxazolone release from the coupling products, by basic hydrolysis proceeds conformely to a zero order kinetics, proving their retard activity

Catalase Immobilized on Poly(Acrylic Acid-co-Vinyl Alcohol)

The paper studies the reaction of catalase’s immobilization on a synthetic polymer (copolymer of the acrylic acid with vinyl alcohol), through amidation of enzyme’s terminal amine groups with the lateral carboxylic group of the macromolecular support, as activated by dicycloxexyl carbodiimide. The support, possessing the properties of a hydrogel, has been synthesized through copolymerization of the acrylic acid with vinyl acetate, followed by hydrolysis of the acetate groups to the hydroxylic groups. The influence of some reaction parameters (such as the activator/support and enzyme/support ratios, duration) on the efficiency of the enzyme’s coupling was studied. The coupling reactions were realized conformely to a centered, rotator, composed, second order experimental program, which permitted the establishment of the conditions necessary for obtaining a coupling product containing the highest amount of immobilized enzyme. Kinetic study of the reaction catalyzed by the coupling products has indirectly evidenced enzyme’s immobilization to the macromolecular support, and also, a sufficiently high catalytic activity of the enzymatic preparation obtained

Furazolidone Immobilized in a Hydrogel Based on Crosslinked Carboxymethyl Cellulose

The paper deals with the obtainment of a polymer-drug system with controlled release of the biological active principle, based on furazolidone included in a hydrogel obtained by crosslinking of carboxymethylcellulose with epichlorohydrine. The influence of temperature and duration of crosslinking reaction on the crosslinking degree of carboxymethylcellulose (indirectly appreciated by its swelling capacity in polar liquids as water and dimethylformamide/water mixtures) is studied. Kinetic data concerning the inclusion of furazolidone from solution, in the hydrogel of crosslinked carboxymethylcellulose, as well as the release of the drug from the obtained polymer-drug system, are performed. The obtained results evidence that the inclusion rate as well as the amount of furazolidone diffused into the support depend on the dymethylformamide/ water ratio utilized as solvent, and on the drug concentration in solution. The product obtained through the insertion of furazolidone from a DMF/water mixture = 5/1 (with a content of 8.9 mg drug/hydrogel) was studied as to the kinetics of the active principle’s release, in vitro, by using as an eluent a buffer solution, which simulates the gastric fluid (pH = 2.4). The experimental results prove the obtention of a polymerdrug system with controlled release of the biologically active principle, conform to a zero order kinetic, in the time interval ranging between 3 – 12 hours

Optimized synthesis of new N-mustards based on 2-mercaptobenzoxazole derivatives with antitumor activity

New di-( -chloroethyl)-amides of some acids derived from 2-mercaptobenzoxazole were prepared by reaction of the corresponding pivalic mixed anhydrides with di-( -chloroethyl)-amine. A study regarding the optimization of the chemical reactions was made for the case of di-( -chloroethyl)- amines. The quantum chemical analysis by Spartan’14 was made in order to establish the most stable configuration of the ground electronic states for the obtained chemical structures and some physicochemical parameters of N-mustards reported in this paper. Mercaptobenzoxazoles substituted in the side chain with the cytotoxic group show antitumor activity and they inhibit Ehrlich Ascites in an appreciable proportion compared to the drug I.O.B.-82, as our studies evidenced

New Di-(β-chloroethyl)-α-amides on N-(meta-Acylaminobenzoyl)- D,L-aminoacid Supports with Antitumoral Activity

In order to obtain new compounds with antitumoural action the N-(metaacylaminobenzoyl)-α-acylaminobenzoyl)-α-aminoacids 4-9 were prepared. Thesecompounds were subsequently converted into the corresponding δ2-oxazolin-5-ones 10-15,which in turn were submitted to a ring opening reaction with di-(β-chloroethyl)amine toafford the peptide supported N-mustards 16-21, which showed low toxicity and cytostaticactivity similar to that of sarcolisine against the Ehrlich ascite and Walker 253carcinosarcoma

Synthesis and microbiological action of new dipenicillins and dicephalosporins derived from asparagic acid

1467-1471A new synthetic method of some β-lactamic antibiotics containing an asparagic acid residue is described which is based on the acylation of the 6-aminopenicillanic acid (6-APA) and of the 7-aminodesacetoxycephalosporanic acid (7-ADCA), respectively, by acid dichlorides of the N-(o,m,p)-nitrobenzoyl asparagic acids at low temperatures in nonaqueous medium. The structure of the newly synthesized compounds has been elucidated by means of elemental analysis and spectral dam (IR, UV,NMR) and their antibacterial activity has been evaluated

Bucharest) ♦ 61♦ Nr

The optimal conditions for the reaction of N-(p-nitrobenzoyl

Synthesis and Antimicrobial Activity of Some New 1,3,4-Thiadiazole and 1,2,4-Triazole Compounds Having a D,L-Methionine Moiety

New 1,3,4-thiadiazole, 5a-e, and 1,2,4-triazolecompounds 6a-c, containing a D,L-methionine moiety were synthesized by intramolecular cyclization of 1,4-disubstituted thiosemicarbazides 4a-e in acid and alkaline media, respectively. The potential antimicrobial effects of the synthesized compounds were investigated using the Staphylococcus aureus ATCC 25923, Bacillus antracis ATCC 8705, Bacillus cereus ATCC 10987, Sarcina lutea ATCC 9341 and Escherichia coli ATCC 25922 strains. The newly synthesized compounds exhibited promising activities against Bacillus antracis and Bacillus cereus

Drug Delivery Systems Based on Pluronic Micelles with Antimicrobial Activity

Bacterial oral diseases are chronic, and, therefore, require appropriate treatment, which involves various forms of administration and dosing of the drug. However, multimicrobial resistance is an increasing issue, which affects the global health system. In the present study, a commercial amphiphilic copolymer, Pluronic F127, was used for the encapsulation of 1-(5′-nitrobenzimidazole-2′-yl-sulphonyl-acetyl)-4-aryl-thiosemicarbazide, which is an original active pharmaceutical ingredient (API) previously synthesized and characterized by our group, at different copolymer/API weight ratios. The obtained micellar systems, with sizes around 20 nm, were stable during 30 days of storage at 4 °C, without a major increase of the Z-average sizes. As expected, the drug encapsulation and loading efficiencies varied with the copolymer/API ratio, the highest values of 84.8 and 11.1%, respectively being determined for the F127/API = 10/1 ratio. Moreover, in vitro biological tests have demonstrated that the obtained polymeric micelles (PMs) are both hemocompatible and cytocompatible. Furthermore, enhanced inhibition zones of 36 and 20 mm were observed for the sample F127/API = 2/1 against S. aureus and E. coli, respectively. Based on these encouraging results, it can be admitted that these micellar systems can be an efficient alternative for the treatment of bacterial oral diseases, being suitable either by injection or by a topical administration