UV -Radiation wavelength 200-700nm -Electrons in bonds excited to occupy higher quantum state and in process absorb some energy passing through -The more loosely held electrons are within the bonds of molecules, the longer the wavelength (lower the energy) of the radiation.Robust workhorse method for the quantification of drugs in formulations where there is no interference from excipients -Determines Pka- SOLUBILITY, and PARTITION COEFFECIENTS values of some drugs -Used to determine dissolution testing (DISSOLUTION TESTING) -Can be used to monitor the REACTION KINETICS of drug degradation -Used as Pharmacopoeial IDENTITY CHECK STRENGTHS - Easy to use, cheap, and robust method offering good PRECISION for making QUANTITIATIVE measurements of drugs in formulation - Routine method for determining some PHYSICO-CHEMICAL properties of drugs -Some problems of the basic method can be solved by use of DERIVATIVE SPECTRA LIMITATIONS -Only MODERATLY SELECTIVE -Selectivity depends on CHROMOPHORE of drug -Colored drug with an extended chromophore is more distinctive than a drug with a simple benzene ring chromophore IR -Electromagnetic radiation ranging from 2500 and 20000nm -Radiation is passed through sample and is absorbed by the bonds of the molecules in the sample causing them to stretch or bend -The wavelength of radiation absorbed is characteristic of the bond absorbing it -a QUALITATIVE FINGERPRINT check fro identiy or faw material used in manufacture and identification of drugs Used in SYNTHETIC CHEMISTRY as a preliminary check fro compound IDENTITY -Can be used to CHARACTERIZE samples in the SOLID/SEMISOLID states such as creams and tablets -Used as FINGERPRINT test for films, coating, and packaging plastics -Can be used to detect POLYMORPHS of drugs STRENGTHS -Provides complex FINGERPRINT which is unique to the compound being examined -Computer control of instruments means that matching of the spectrum of a compound to its standard fingerprint can now be readily carried out LIMITATIONS -Rarely used as a quantitative technique because of relative DIFFICULTY in sample preparation and the COMPLEXITY OF SPECTRA -Usually can only detect GROSS IMPURITIES in samples -Sample preparation requires a degree of SKILL, particularly when POTASSIUM BROMIDE (KBr) Discs are being prepared - The technique is lacking robustness NMR -Radiofrequency is 60 mHz - Used to usually excite carbon 13 atoms -The range of frequencies required for excitation and the complex splitting patterns produced are very characteristic of the chemical structure of the molecule - Powerful technique for the CHARACTERIZATION of the EXACT STRUCTURE of raw materials and finished products -Can determine IMPURITIES, including ENANTIOMERIC IMPURITIES, without separation, down to a ca the 10% level -Can potentially be used for FINGERPRITING mixtures -Has good potential for QUANTITATIVE ANALYSIS of drugs in formulations PRIOR separation STRENGTHS -Provide MOST information about MOLECULAR STRUCTURE than any other technique LIMITATIONS -A relative intensive technique requiring >5mg of sample for proton nuclear magnetic resonance (NMR) and >20 mg for carbon-13 NMR -EXPENSIVE instrumentation requiring SPECIALIST MASS SPEC -Charged molecules(molecular garments( are generated in a HIGH VACUUM region, or immediately prior to a sample entering a high vacuum region, using a variety of methods for ion production. -The ions are generated in the GAS PHASE so they can be manipulated by the application of either electric or magnetic fields to enable the determination of their molecular weights -Provides a HIGHLY SPECIGIC method for determining IDENTITY or STRUCTURE of drugs and raw material in their manufacture -Can be used with GC or LC for characterizing impurities in drugs and formulation excipients - GC-Mass Spec and LC-Mass Spec provide highly sensitive methods for determining drugs and their metabolite in biological fluids and tissues -Important tools in PROTEOMICS which is currently a major tool in drug discovery STRENGTHS -BEST method for getting rapid identification of TRACE IMPURITIES, which should ideally be carried out using chromatography separation in CONJUNCTION with HIGH RESOLUTION MASS SPEC(the technique will be of major use in the quality control of therapeutic ANTIBODIES and PEPTIDES LIMITATIONS -Not currently used in routine quality control (QC) but is placed in research and development (R & D) environment. -Is EXPENSIVE and requires support by HIGHLY TRAINED personnel and regular maintenance. jszabo
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