Iraqi National Journal Of Chemistry

Two simple, rapid and sensitive spectrophotometric methods have been developed for the determination of chloramphenicol (CAP) in pure form and in pharmaceutical preparations. The proposed methods are based on a coupling reaction between reduced chloramphenicol (by zinc powder and concentrated hydrochloric acid) with chromatropic acid or phenol in the presence of ammonium hydroxide to form an intense red violet or yellow color, water-soluble dyes that are stable and have a maximum absorption at 515 nm using chromatropic acid and 432 nm on using phenol. The calibration graphs were linear over the concentration ranges of 0.52 -12 µg mL-1 and 0.4- 18µg mL-1 with a limit of detection (LOD) of 0.1334 µg mL-1 and 0.0873 µg mL-1 for chromatropic acid and phenol, respectively. The proposed methods were successfully applied to the determination of CAP in ointment and eye drops.

Tetracycline hydrochloride (TCH) was determined spectrophoto-metrically in the pure form and in the pharmaceutical formulations using flow injection analysis (FIA). The automated method is based on the reaction between TCH, sodium nitroprusside and hydroxylamine hydrochloride in alkaline medium. The product absorbed maximally at 529 nm. The calibration graph of TCH is linear from 25-1000 µg mL-1 with detection limit (S/N=3) of 7.589 µg mL-1 and sample through put of 69 h-1. The various chemical and physical variables were optimized and the proposed procedure was applied successfully for estimation of drug in different commercial forms.

Several poly(alkylene sulfone)s have been synthesized in excellent yields from reactions of poly(alkylene sulfide)s with H2O2 at 25 C for 24 h. The structure of the poly(alkylene sulfone)s obtained was confirmed by 1H NMR, 13C NMR. Different properties have been studied such as melting point and molecular weight

New Schiff bases derivatives [IV]a-e is prepared via condensation of D-erythroascorbic acid with p-substituted aldehydes in dry benzene. To obtain these derivatives, the 5,6-O-isopropylidene-L-ascorbic acid[I] was chosen as starting material, compound prepared from the reaction of L-ascorbic acid as starting material. Compound[I] was prepared from the reaction of L-ascorbic acid with dry acetone in the presence of hydrogen chloride. The esterification of hydroxyl groups at C-2 and C-3 positions with excess ofethyl α –chloroacetate in the presence of sodium acetate produce acorresebonding ester [II] , which was condensed with hydrazine hydrate to give new hydrazide [III] . The new Schiff bases [IV]a-e were synthesized by reaction of acid hydrizide with different p-substituted benzaldehyde in dry benzene . The new 1,3-oxazepine derivatives [V]a-ewere obtained by Diels-Alder reaction of Schiff bases with phthalic anhydride in dry benzene (Scheme 1) . All the synthesized compounds have been characterized by melting points , FTIR and 1HMNR (of some of theme) spectroscopy. The biological activity of synthesized compounds was examined against two types of bacteria; G(+) and G(-).

The purpose of this study is to develop colon-specific drug delivery systems with pH-sensitive drug release properties.The azo polyurethane were characterized, and the drug content of the azo polyurethane was determined.Their behaviour and hydrolytic degradation was studied in simulated gastric fluid (SGF, pH =4) and simulated intestinal fluid (SIF, pH =7.8). All synthesized monomers and polymers were characterized by FTIR, 1H-NMR spectra.The release of 5-ASA under physiological conditions (pH = 7.8 and pH = 4) was investigated at body temperature (37 ºC). The release rate of 5-ASA increased with increasing pH (7.8 > 4).

A series of new aromatic polyimides (Pi1 - Pi6) containing methylene unit, flexible ether linkages (containing naphthalene rings), and Schiff-base linkages were prepared by solution polycondensation reaction of 1,2,4,5-benzene tetracarboxylic dianhydride (BTDA) with new various aromatic diamines using a standard two-stage process with thermal imidization of poly(amic acid) films. The monomers were characterized by FT.IR, and some them by 1H. NMR. The resulting polymers were characterized by means of FT.IR, 1H.NMR spectroscopy, and solubility tests. All polyimides were readily soluble in polar aprotic solvents. The thermal stability, melting temperature and glass transition temperature of these polyimides were measured using differential scanning calorimetry (DSC). These polymers formed tough flexible films by solution casting.

Synthetic route to a series of tin compounds incorporating nitrogen-based chelating ligands are described. The β-diketiminatotin chloride precursor was utilised to isolate the first tin-phosphorus tin compound using this ligand, [(HC{C(Me)NAr}2)SnPPh2]. The reactivity of the tin-phosphorus bond was probed by reaction with elemental selenium, resulting in direct insertion into the bond. A diamide ligand was employed to investigate this type of ligand in tin II and IV compounds. Two tin(IV) compounds, [(Me2Si{ArN}2)SnPh2] and [Li(OEt)2](Me2Si{ArN}2)SnPh2], were formed via reaction of the lithiatedpreligand, [Me2Si{ArNLi}2], with SnCl4. And finally a novel Sn(II) N-heterocyclic stannylene compound was formed by reaction of the preligand with SnCl2.

This research included isolation of uricase from the seeds of leek (Allium ampeloprasum ), celery(Apium graveolens) and arugula(Eruca sativa). Studied the factors effecting its activity and determination of its molecular weight. One proteinous peak had been isolated by gel filtration (using sephadex )G-100)) from the proteinous supernatant obtained using ammonium sulfate saturation(70%). The apparent molecular weight of the isolated enzymes using gel filtration chromatography were (59600+ 209) Dalton for leek, (59430+ 221) Dalton for celery and (59800+ 190) Dalton for arugula .The results also showed that the optimum conditions for the activity of uricase isolated from seeds of leek, celery and arugula obtained at (100 µg/ml) of enzymes concentration using (100, 100 and 120 mmol/l) of uric acid as a substrate, with borate buffer solution at pH (7.0, 7.0, 6.5 ) for (15) minutes at (40, 40 and 35 C) respectively. Using Line Weaver–Burk plot, the values of maximum velocity (Vmax) and Michaelis constant (Km) were from to be (33.3 µmol/ min) and (83.3 mmol/l) for leek, (40 µmol/ min) and (285.7 mmol/l) for celery while (27 µmol/ min) and (166.6 mmol/l) respectively for arugula. When using 100 mM chemical compounds for mercuric chloride(HgCl2), ferrous chloride (FeCl2) and ethylene diamine tetra acetic acid (EDTA) showed decreased the activity of the enzyme, but calcium chloride (CaCl2), manganese sulphate (MnSO4), magnesium sulphate (MgSO4) and potassium chloride (KCl) increased the activity .