Bollettino chimico farmaceutico最新文献

Hydrogels, based on polyacrylic acid and various macrodiisocyanates that contain polyethylene glycol, polypropylene glycol or polytetramethylene glycol in the main chain are synthesized. The obtained hydrogels are studied as possible polymer carriers of drug substances. Etophylin was applied as a model drug. It is exposed that the etophylin release rate from the hydrogel depends on the way of drug comprise in the polymer net, from its density from the chemical nature of the crosslinking agent and from the pH of the environment. The carried out studies let us to conclude that the obtained hydrogels are possible materials as drug carriers.

A variety of 2-substituted-4, 6-diaryl-3-pyridinecarboxylates 4 were obtained through aromatic nucleophilic substitution. reaction of secondary amines with 2-bromo-3-pyridinecarboxylate derivatives 3. The latters were obtained through bromination of 3-aryl-4-benzoyl-2-cyanobutyrates 2 in glacial acetic acid. However; reaction of primary aromatic amines with 2-bromopyridines 3 afforded 2-arylamino-3-pyridinecarboxylates 5 beside the unexpected 2-amino analogues 6. On the other hand, 3-hydroxy-1H-pyrazolo[3,4-b]pyridines 7 were isolated via reaction of 3 with hydrazine hydrate. Good to complete muscle relaxation of rabbit's jejunium, rat's uterus and rabbits aorta was observed during screening representative examples (3a, 4c, Sd, 5f and 6b) of the newly synthesized 3-pyridinecarboxylates indicating the vasodilatation and antihypertension activity for the tested compounds.

A non-bitter chloroquine suspension formulation for pediatric use was prepared in the form of an ion-pair of chloroquine with pamoic acid. Various parameters involved in the formulation of a stable and palatable suspension have been optimized. The suspension was characterized for particle size analysis, viscosity, physical and chemical stability and taste. Release of chloroquine from the ion-pair conducted as dissolution rate studies in simulated gastric media showed near to 100% release instantaneously. In-vivo bioavailability study conducted in albino rats indicated comparable bioavailability of chloroquine from the suspension with that of chloroquine phosphate syrup taken as standard. Stability study conducted over a period of 3 months showed the intactness of the ion-pair and the tasteless behavior of the suspension throughout the period of storage.

Chitosan hydrogel beads containing diclofanac sodium were prepared using ionotropic gelation technique in which tripolyphosphate solution was used as a counterion. Chitosan molecular weight, tripolyphosphate concentration and crosslinking time were found to have an effect on the percentage of the drug loading. The loading efficiency of diclofenac sodium was very high (more than 90%). A longer-period of contact with the counterion ions decreased the efficiency of drug loading. The beads produced all had good spherical geometry. The beads showed a narrow size distribution in which 95% of the beads prepared were in the range of 2-3 mm. Comparison of release rate-time plots of dissolution data of marketed product with the newly developed dosage form indicated the ability of the later to sustain more diclofenac sodium release. The beads were evaluated for their bioavailability in six beagle dogs relative to the commercial enteric-coated Voltaren tablets. The in vivo availability study, reveled that the prepared beads filled in hard gelatin capsules had a 126.22% bioavailability relative to that of the commercial Voltaren tablets. The beads showed comparable pharmacokinetic parameters to that of the commercial tablets. The results suggested the possibility of producing a promising sustained drug delivery system for diclofenac sodium.

Photooxygenation reaction of ã -terpinene (1) in the presence of tetraphenyl porphine (TPP) or Rose Bengal (RB) gave 2, 5-dihydroperoxy-1-isopropylene-4-methylene-cyclohexane (2), 3,6-dihydroperorxy-3-isopropyl-6-methyl-2,4-cyclohexadiene (3) and 1,2&4,5-diepoxy-1-isopropyl-4-methylcyclohexane (4). The epoxide 4 was also synthesised through the epoxidation reaction of ã-terpinene (1) with m-chloroperbenzoic acid (mcpba).

In an attempt to design and synthesize more potent quinoline-based chemotherapeutic agents structural modifications of 5, 7-Dibromo-2-methyl-8-benzoyloxyqinoline was carried out. The replacement of the bromine atoms with the requisite alkylamino compound gave four amino-derivatives viz: bis(dipropylamino)-dipyrrolidino-, dipiperidino- and dipiperazino derivatives. The antimicrobial activities of these compounds were investigated against selected Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis), Gram-negative bacteria (Escherichin coli, Pseudomonas aeruginosa and Klebsiella spp) and yeast (Candida albicans). All the compounds showed broad or significant antimicrobial activity, which varied from two to ninety times that of the parent compound. The dipyrrolidino derivative was the most effective against Gram-positive bacteria and yeast while the dipiperidino derivative was the most effective against Gram-negative bacteria. No correlation has been established between the minimum inhibitory, (MIC) concentrations of the derivatives and the structural modifications.