Jarubol Chaichana Bureau of Drug and Narcotic Department ...

1 JarubolChaichanaBureau of Drug and NarcoticDepartment of Medical Sciences2 March 20121 Principle -The titrimetricdetermination of water is based upon the quantitative reaction of water with an anhsolution of sulfur dioxide and iodine in the presence of a buffer that reacts with hydrogen 1a (Direct Titration)<921>Water DeterminationUSP34 Principle -The semi-micro determination of water is based upon the qunatitativereaction of water with sulfur dioxide and iodine in a suitable anhmedium in the presence of a base with sufficient buffering 1( )Determination of Water BP 2012In the volumetric titration method, iodine required for reaction with water is previously dissolved in water determination, and water content is determined by measuring the amount of iodine consumed as a result of reaction with water in a This is a specific method. Only water will be determined. The method is rapid (a few minutes). With KF titration both free and bound water can be determined, surface water on crystals or the water containedinside them.

2 5 Cloxacillin sodium (BP2012).( .12) Water : % to %, determined on g It is indicated that when determined by accurately weighed about g of the sample and performing KF Titration, the water content is NLT % and NMT % of the sample KF Titration7 Analytical balance (min resolution mg) Syringe with long, thin needle karl fischer reagents for volumetric water determinationKF instrument should not be set up in areas that are subject to large temp fluctuations, high humidity. They must not be placed in the proximity of heating, cooling reagentAutomatic BuretteTitration flaskMethanolPlatinum electrodesThe titration apparatus should be protected from atmospheric close system Iodine Sulfur dioxide Buffer SolventI2SO2 ImidazolMethanol10 HYDRANAL karl fischer HYDRANAL reagents uses imidazoleor diethanolamineas a base, rather than noxiouspyridine. Imidazoleand diethanolamineare bothsafe and effective and guarantee reliable analyses. Replacement of noxious pyridine with basesthat are both safer and more effective.

3 112 Steps1213 Standardization USP3414 Standardization BP201215 SubstanceRemarksWater contentPurified waterIdeal if technician knows how to water standardsNot hygroscopic Balance essential with test certificate10 mg/g &1 mg/gFill MeOHin the titration flask to cover the electrodes. Condition system to conditioning drift OK (<20 L/min). Quickly add the water standard, accurately weighed containing 20 to 25 mg of water into the titration flask, stir and titrate until the The water equivalent is NLT 80% of that indicated by the = the water equivalency factor of the Reagent, in mg/mLKF = the limit or reasonable expected water content in sample, in%C = the used volume, in %, of the capacity of the buretV = the buretvolume, in mLC is generally between 10%-100% for the instrument method the water content of the specimen, in mg, taken by the formula:SFWater content (%)= SF x 100 mg of Test Preparation23 BivoltametryIpol= 50 ACurrent applied to a double Pt electrodeDuring titration: Excess H2O High voltage between the Pt wiresAt the end of titration.

4 Small excess of free iodine Voltage decreases sharplyDrift in l/minStop at 6 l/minEnter the sampleTime in sBasis 6 l/min25 Water content of sample(absolute content in g)Maximal permittedRSD%<500 (< mg)Not reported500-1000 ( ) ( ) ( ) ( ) g of Standard water is equivalence to KFR mLTiter = x 1000= g of LidocaineHClis eq. to KFR mLwater content(%) = x x 100= USP34 (LidocaineHCl) : between and : Pass28