[Developing and application of an autoverification system for clinical chemistry and immunology test results].

Objective: To develop and validate an autoverification system for biochemistry and immunology test results for application in routine work. Methods: Algorithms was designed and translated into the laboratory information system. Parameters including verify limit, delta check, logic relation between tests was set up in the system. Verification rate of every test and the causes of fails were analyzed, according to which the system and parameters were modified. The autoverified reports were evaluated by chief technicians. Only when all of the autoverified results pass the evaluation, the system applied for routine work of releasing the results. Autoverification rate and turnaround time(TAT) were calculated for evaluation of the efficiency of the system. Results: A brand new autoverification system was developed and applied for routine work. The autoverification rate for each single test was 91.1%-96.6%. The autoverification rate for reports was 74%. With the autoverification system, the media of TAT reduced from 111.6(53.9-270.7) min to 87.2(45.4-202.4) min, whereas the time from instrument finishing analysis to releasing the reports reduced from 18.6(1.0-99.3) min to 0.1(0-58.3)min. The number of staff specified for results validation reduced from three to one. Conclusions: The newly developed system can be used for autoverification of biochemistry and immunology test results. The autoverification system can greatly reduce TAT and raise working efficiency. It's essential to employ carefully designed algorithm, appropriate parameters and comprehensive evaluation when developing a new autoverification system.

Tandem mass spectrum of a farnesyl transferase inhibitor--gas-phase rearrangements involving imidazole.

Compound 1 (1-(3-chlorophenyl)-4-[1-(4-cyanobenzyl)imidazolylmethyl]-2-piperazinone hydrochloride) is a farnesyl transferase inhibitor intended for treatment of cancer. A detailed analysis of the electrospray ionization mass spectrometry and tandem mass spectrometry data of protonated 1 shows that in the gas phase, upon collision-induced dissociation, this ion undergoes complicated rearrangement and fragmentation. These processes include a novel two-step rearrangement. The first step involves a gas-phase intramolecular S(N)2 reaction that forms an intermediate. The second step consists of three competitive rearrangement/fragmentation pathways of the intermediate, giving rise to protonated 2, protonated methylene-imidazole, and a distonic methylimidazole radical cation. Deuterated 1 was studied under the same experimental conditions, and the results strongly support the proposed two-step rearrangement process. It is noted that the unique structure of 1, especially the imidazole ring of 1, plays a critical role in the rearrangement of protonated 1.

Collision-induced dissociation of protonated MK-0991: novel ring opening of a cyclic hexapeptide in the gas phase.

Electrospray ionization tandem mass spectrometry was applied to probe the collision-induced dissociation (CID) of protonated MK-0991 {(4R,5S)-5-[(2-aminoethyl)amino]-N(2)-(10, 12-dimethyl-1-oxotetradecyl)-4-hydroxy-L-ornithyl-L-threonyl-trans -4- hydroxy-L-prolyl-(S)-4-hydroxy-(4-hydroxyphenyl)-L-threonyl-threo-3-h ydroxy-L-or-nithyl-trans-3-hydroxy-L-proline cyclic (6-1)-peptide} in the gas phase; MK-0991 is a newly developed, broad-spectrum pneumocandin antifungal drug. The study showed that protonated MK-0991 (m/z 1094) undergoes specific ring opening under the CID conditions to form two protonated linear peptides at m/z 1076 and 1034. This is different from the commonly observed ring opening of a cyclic peptide that occurs by the cleavage of the N-acyl bonds in many places on the peptide backbone. The structures of the two linear peptides were elucidated on the basis of their tandem mass spectra. The results strongly indicate that the specific ring opening of MK-0991 is affected by the ethylenediamine side-chain formed from the modification of one of the ornithine amino acids in this cyclic hexapeptide.

Identification of losartan degradates in stressed tablets by LC-MS and LC-MS/MS.

Three unknown peaks were observed in the severely stressed losartan tablets (at 40 degrees C and 75% relative humidity for 3 years) analyzed by a stability indicating HPLC method. The sample solutions were subjected to liquid chromatography-tandem mass spectrometric (LC-MS/MS) analysis to obtain the chemical identities of these potential degradates. High accuracy and sensitivity of losartan and its degradates were obtained by using atmospheric pressure chemical ionization (APCI) technique in the LC-MS/MS analysis. Three trace level degradates (< or = 0.1%) were found to be the aldehyde and dimeric derivatives of losartan. The structural assignment was further confirmed by comparing the tandem mass spectra of the unknowns with those of the authentic materials of each corresponding degradate. Finally, the mechanistic pathways for the formation of the dimers are discussed.

Pharmaceutical application of LC-MS. 1--Characterization of a famotidine degradate in a package screening study by LC-APCI MS.

The application of LC-MS to characterize low-level degradates in pharmaceutical dosage formulations is a new and challenging field. In a package screening study, a low-level degradate of famotidine (1, 3-[[[2-[[aminoiminomethyl]-amino]-4-thiazolyl]methyl] thio]-N-(aminosulphonyl)-propanimid-amide, an H2-receptor antagonist, molecular weight: 337) was detected by HPLC in film-coated tablets packaged in child-resistant (CR) foil pouches which were stressed at 40 degrees C/75% relative humidities (RH) for 4 months. LC-atmospheric pressure chemical ionization (APCI) mass spectrometry using positive ion mode yielded a molecular weight of 349 for the degradate, suggesting that it was formed by the addition of one carbon to the famotidine molecule. A detailed analysis of the positive product ion mass spectrum of the protonated degradate ion in a LC-MS-MS study indicated that the carbon was added to the side of N-(aminosulphonyl)-propanimid-amide of famotidine. The structure of the degradate was determined to be 2, which was confirmed by LC-APCI MS and HPLC study of the product formed from the reaction of famotidine with formaldehyde--a one-carbon reagent.

Use of near-infrared spectroscopy to evaluate an active in a film coated tablet.

PURPOSE: To provide a method to rapidly screen tablets in the development of new coating technology. METHODS: Near-Infrared (NIR) reflectance spectroscopy was used to quantitatively analyze tablets which were composed of a drug active encasing an active drug core. Diffuse reflectance NIR scans of 240 individual tablets over the range of 1100-2500 nm were obtained. High Performance Liquid Chromatography (HPLC) was used as the reference method. RESULTS: Both qualitative, Principal Component Analysis, and quantitative results showed a strong agreement between the NIR and HPLC methods. The NIR analysis was non-invasive and allowed subsequent testing of the tablets. The contents of the drug active contained in a drug coating was determined to +/- 4% of the target value using NIR analysis. Over 400 samples were analyzed in less than a month utilizing this technique which allowed the optimization of a new coating technology. CONCLUSIONS: NIR analysis allowed the evaluation of the efficiency of a new drug film coating manufacturing process more quickly and inexpensively. Because the Near-Infrared method was non-invasive the tablets were available for further analysis unlike the chromatography method.