Isonicotinic acid hydrazide reagent

Isonicotinic acid hydrazide reagent 318 Isoprenaiine 395,396 Isoprenoid compounds 44 Isopulegol 59 Isoquercitrin 279, 280, 323 Isoquinoline alkaloids 46, 66, 262 Isorhamnetin 323 Isothiazolones, microbiocidal 45 Isothiocyanates 75 Isotopes, j8-radiation-emitting 41 -, detection limits 41 Itaconic acid 61... 

Detection. Layer dipped into isonicotinic acid hydrazide reagent for 20 s and then into chloroform-liquid paraffin (9 1) to enhance and stabilize fluorescence. 

Condensation of isoniazid (isonicotinic acid hydrazide) with any a" -3-ketosteroid in acidic medium affords a yellow color conjugate, allowing the determination of 10-40 pg of the steroid [73]. The reagent is prepared by dissolving 0.8 g of isoniazid in 100 mL of methanol containing 1 mL of concentrated HCl, and then 12.5 mL of this solution is further diluted to 100 mL with methanol. To a 2 mL methanolic sample solution of the 3-ketosteroid is added 2 mL of the reagent. The mixture is allowed to stand at room temperature for an hour, and then the absorbance of the resulting colored solution is measured at 380 nm. In a 1 cm spectrophotometer cell, an absorbance of 0.3 will be produced by 42 pg of cortisone, 34 pg of prednisolone, 29 pg of prednisone, or 32.5 pg of dexamethasone [72]. 

Sastry et al. used iodine and isonicotinic acid hydrazide for the spectrophotometric determination of diloxanide furoate in tablets and in syrups [30]. Powdered tablets or syrup were dissolved in methanol and hydrolyzed under reflux with dilute hydrochloric acid. The mixture was cooled, and excess HCI removed under vacuum. The hydrolysate was dissolved in and diluted with water. Iodine solution and the isoniazid solution were added at two minute intervals to a potassium h) drogen phthalate/HCl buffer solution (pH 3), and diluted with water. The solution was set aside for 10 minutes, whereupon the absorbance was measured at 630 nm against a reagent blank. 

GABA synthesis inhibitors act on the enzymes involved in the decarboxylation and transamination of GABA. Glutamic acid decarboxylase (GAD), the first enzyme in GABA biosynthesis, is inhibited easily by carbonyl reagents such as hydrazines [e.g., hydrazinopropionic acid (4.164) or isonicotinic acid hydrazide (4.165)], which trap pyridoxal, the essential cofactor of the enzyme. A more specific inhibitor is allylglycine (4.166). All of these compounds cause seizures and convulsions because they decrease the concentration of GABA. 

Reaction of 1,4—diene-3-ketosteroids with isonicotinic acid hydrazide (isoniazid) produces a yellow hydrazone with an absorption maximum of 404 mp38. This reaction can be adapted to triamcinolone for formulation assays. It also has been used as a spray reagent and for quantitation in paper and thin layer chromatography... 

Blue tetrazolium (BT) and Phenylhydrazine H2SO4 (PH) reagents react with the intact side chain at C17 of prednisolone while isonicotinic acid hydrazide (INH) and UV-absorption depend upon conjugation in Ring A at the other end of the prednisolone molecule. Since... 

Spray reagent 1 g isonicotinic acid hydrazide and 1 ml acetic... 

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