SYNTHESIS AND EVALUATION OF NEW PHTHALAZINE SUBSTITUTED ß-LACTAM DERIVATIVES AS CARBONIC ANHYDRASE INHIBITORS.

A new series of phthalazine substituted ß-lactam derivatives were synthesized and their inhibitory effects on the activity of purified human carbonic anhydrase (hCA I and II) were evaluated. 2H-Indazolo[2,1-b]phthala- zine-trione derivative was prepared with 4-nitrobenzaldehyde, dimedone, and phthalhydrazide in the presence of TFA in DMF, and the nitro group was reduced to 13-(4-aminophenyl)-3,3-dimethyl-3,4-dihydro- 2H-indazolo[1,2-b]phthalazine-1,6,11(13H)-trione with SnCl2 · 2H2O. The reduced compound was re- acted with different aromatic aldehydes, and phthalazine substituted imines were synthesized. The imine compounds undergo (2+2) cycloaddition reactions with ketenes to produce 2H-indazolo[2,1-b]phthala-zine-trione substituted ß-lactam derivatives. The ß-lactam compounds were tested as inhibitors of the CA isoenzyme activity. The results showed that all the synthesized compounds inhibited the CA isoenzyme activity. 1-(4-(3,3-dimethyl- 1,6,1 1-trioxo-2,3,4,6,11,13-hexahydro-1H-indazolo[1,2-b]phthalazin-13- yl)phenyl)-2-oxo-4-p-tolylazetidin-3-yl acetate (IC50 = 6.97 µM for hCA I and 8.48 µM for hCA II) had the most inhibitory effect.

The effects of bronchodilator drugs and antibiotics used for respiratory infection on human erythrocyte carbonic anhydrase I and II isozymes.

Carbonic anhydrase (CA) is an enzyme which plays role/roles in various homeostatic mechanisms, such as the acid-base balance and electrolyte secretion in various tissues. This study aimed to determine and to compare possible alterations in activity of this enzyme caused by use of bronchodilator drugs and respiratory infection antibiotics. CA I and II were purified from human erythrocytes by a simple one step procedure using Sepharose 4B-L-tyrosine-sulfonamide affinity column. The iso-enzymes were purified 259.16-fold with a yield of 31.74%. CAI and II isozymes were treated with several drugs, then the inhibition or activation of the enzymes were determined. The results of this study show that itrapropium bromide is the most effective inhibitor for human erythrocytes carbonic anhydrase compared with the other bronchodilator drugs.

The effects of anti-epileptic drugs on human erythrocyte carbonic anhydrase I and II isozymes.

Carbonic anhydrase (CA) is an enzyme which plays a role in various homeostatic mechanisms, such as acid-base balance and electrolyte secretion in a various tissues. This study was aimed at determining and comparing possible alterations in activity of this enzyme caused by the use of old (Carbamazepine, Phenytoin Sodium, Sodium Valproate) and new (Levetiracetam, Pregabalin, Gabapentin, Oxcarbazepine) anti-epileptic drugs. Blood samples were collected from the volunteers. The blood samples were centrifuged to separate plasma and erythrocyte package. Hemolysate was prepared from the red cells. CA I and II were purified from human erythrocytes by a simple one step procedure using Sepharose 4B-L-tyrosine-sulfonamide affinity column. CA I and II isozymes were treated with some anti-epileptic drugs, then the inhibition or activation of enzyme determined. The results of this study show that Levetiracetam is the most effective inhibitor for human erythrocytes carbonic anhydrase compared with the other anti-epileptic drugs.