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Biomedical subjects

B Tilquin

Publications and source records attributed to B Tilquin.

15 recordsLinked to original sources
PubMed2001

Radiosterilization of cefotaxime: investigation of potential degradation compounds by liquid chromatography-electrospray mass spectrometry.

The nonvolatile radiolytic compounds produced by irradiation of cefotaxime were studied by a liquid chromatography-electrospray mass spectrometry method. Full scan LC-MS was first performed in order to obtain the m/z value of the protonated molecules of all detected peaks. LC-MS-MS was then carried out on the compounds of interest. A comparison between the MS-MS spectrum of cefotaxime and those of the radiolytic compounds showed that their fragmentation patterns were very similar suggesting that they were structural analogues of the main drug. The examination of the two main fragmentation pathways also permitted the location of the modified substructures. Moreover, it was shown that some stereoisomers appeared with the irradiation process. The complete fragmentation pattern of cefotaxime was studied by MSn and used to obtain information about the structure of the radiolytic compounds. A complete structure was proposed for four of these.

Cefotaxime↗
PubMed1999

Role of residual solvents in the formation of volatile compounds after radiosterilisation of cefotaxime.

Radiation sterilisation is a promising method to sterilise pharmaceutical products. However, this process is accompanied by a modification of odour due to volatile compounds formation. The origin of malodorous compounds produced during solid cefotaxime radiosterilisation has been investigated and several mechanisms are proposed to explain their appearance. Moreover, some quantitative data are given. Analysis of the degradation products was performed using a GC-ITD system with an injection by the static headspace technique. It appeared that some of the radio-induced compounds (such as carbon oxide sulfide and carbon disulfide) came from the degradation of the drug itself, whereas the formation of others required the presence of residual solvents which are volatile impurities already present before irradiation. Acetaldehyde directly came from impurities but the appearance of esters and acetaldehyde O-methyloxime was due to the presence of both cefotaxime and residual solvents together. Thus, the residual solvents play a key role in the radiolysis compounds formation (six of eight require the presence of them) and consequently in the modification of odour as well.

Cefotaxime↗
PubMed1996

Trace analysis in chiral separation of selected amino enantiomers.

A Crownpack CR(+) column was used for the highly sensitive quantitation of amino acid enantiomers. The use of a mobile phase of exclusively aqueous perchloric acid enabled the use of low-wavelength UV detection (200 nm) before on-line derivatization with o-phthaldialdehyde for fluorimetric detection. The use of simultaneous UV and fluorimetric detection permitted the simultaneous quantification of the impurity and its parent compound. The method was used for the evaluation of some commercially available amino acid standards. Enantiomeric impurities as low as 0.001% (10 ppm) can be determined in some cases. High precision for the determination of trace levels of D-amino acids in the presence of large amounts of corresponding L-enantiomer is demonstrated.

Alanine↗
PubMed1994

Electron spin resonance study of radiosterilization of antibiotics: ceftazidime.

Fundamental information on radiosterilization of ceftazidime was obtained by electron spin resonance (ESR) measurement of free radicals produced in gamma-ray-irradiated ceftazidime at 4.2-295 K. Three types of free radicals are produced by gamma-irradiation. The first one shows septet lines in an ESR spectrum and decays at 230 K: it is assigned as a .C(CH3)2COOH radical. The second one shows triplet lines and decays at 293 K: it is assigned as iminoxyl radicals (> C = N-O.). The third one shows a broad singlet line and survives even at 295 K. The plausible assignment of this spectrum is discussed. It is concluded that an O-C bond of the gamma-irradiated ceftazidime is ruptured, producing the iminoxyl radicals and .C(CH3)2COOH radicals. The yields of free radicals increase linearly with the increasing dose of gamma-irradiation up to 10 kGy at 295 K as well as 77 K. Half of the radicals that show a broad singlet line survive at 295 K upon storage of the irradiated ceftazidime for 159 days. It is concluded that the ESR measurement of free radicals gives a good method for discrimination of irradiated antibiotics from non-irradiated ones and an estimation of an irradiation dose.

Ceftazidime↗
PubMed1994

The Hueston flap in reconstruction of fingertip skin loss: results in a series of 41 patients.

We reviewed 43 Hueston flaps in 41 patients (average age, 35 years) following distal fingertip skin loss. Mean advancement of the flap was 13 mm. Patients with single-digit injuries missed an average of 36 days off work. At the follow-up evaluation (mean, 3 years), 10 patients complained of pain (1 with functional impairment), 30 complained of cold intolerance, and 24 had nail deformities. Sensibility of advanced skin was normal by Semmes-Weinstein test in 33 cases, while two-point discrimination averaged 7 mm. This discrimination was virtually identical to contralateral digits in 31 of the cases. Overall, 30 patients were satisfied with their results, while 11 patients were mildly displeased. In 10 patients, this involved impairment of function, while the remaining patient was displeased with the appearance.

Adolescent↗
PubMed1992

[Reconstruction of distal loss of substance in the nail-bed by a de-epithelialized flap from the digital pulp].

Twelve patients, presenting with traumatic avulsion of the distal nail bed, repaired by a de-epithelialized palmar advancement flap, were reviewed with an average follow-up of 23 months. Subjective results were considered excellent in two cases, good in seven, fair in two and poor in one patient. Nail adherence with the de-epithelialized flap was observed over almost 90% of the new nail bed. Nail dystrophy was observed in three patients, but was severe in only one. Two patients had slight curvature of their nail, while one had a severe hook-nail deformity. Mobility in the finger was always complete, and only one patient had a slightly decreased two-point discrimination on the flap.

Adolescent↗
PubMed1992

[Treatment of post-traumatic swan-neck deformities of the fingers. Apropos of a series of 43 patients].

Thirty three patients with 51 swan neck deformities were reviewed with a mean follow up of 35 months (6 to 86 months). 8 fingers presenting some stiffness necessitated a first step of splinting before operation giving nevertheless 5 excellent and good results. Among the other fingers with full range of passive motion surgery was performed in 38 cases with 81.5 per cent of excellent and good results. According to etiology, articular or extrinsic, excellent and good results were respectively 71 per cent and 94 per cent. The most frequently used operations were Littler type II (12 cases) and Littler type III (S.O.R.L. 11 cases) giving respectively 75 per cent and 82 per cent of excellent and good results, despite frequent minor complications. Tenodesis with translocation of a lateral extensor band gave in half the cases some extension lack at DIPJ (less than 20 degrees in 62.5 per cent). Finally direct surgery of mallet finger complicated by a swan-neck deformity led constantly to good correlation at the PIP level.

Adolescent↗
PubMed1992

[Resection of the tip of the lateral malleolus by Ibister's method in the treatment of painful sequelae of calcaneus fractures].

Persistent pain below the tip of the lateral malleolus may occur after comminuted fractures of the calcaneus. The pain is the result of compression of the peroneal tendons or abutment between the calcaneus and the lateral malleolus. Computerized tomography clearly shows the etiology. In these cases, the excision of the tip of the lateral malleolus, procedure described by Isbister, was performed. The clinical results of fifteen procedures in thirteen patients who had persistent pain below the tip of the lateral malleolus after fracture of the calcaneus are reported. All the patients were completely relieved of lateral pain. Subjectively, for nine patients, the results were excellent (7) or good (2). 4 patients are not satisfied. In these cases, pain arising from the subtalar joint was the main complain.

Adolescent↗
PubMedDate not supplied

[Gas-liquid chromatography with Fourier-transform infrared spectrophotometry. Application in the analysis of drugs. 2: Benzodiazepines].

High working temperatures were used during the separation of benzodiazepines by capillary gas chromatography with Fourier transform infrared detection (FTIR). Spectral identification of these drugs give very good results with 10 micrograms of drug injected. On the contrary, the precision of the quantitative determination is poor.

Benzodiazepines↗
PubMedDate not supplied

[Radiation sterilization of drugs].

Radiation sterilization can be carried out on the final packaged drug, is applicable to heat or ethylene oxyde sensitive compounds and is eased in control and monitoring. Most of the drugs seem to be not affected by irradiation, however it is necessary to be established that any traces of radiolytic products formed are not toxic. E.S.R. is a good detection method for irradiated drug.

Pharmaceutical Preparations↗
PubMedDate not supplied

Pulse radiolysis study of the reactivity of chloramphenicol, diazepam and clonazepam with the electron and the hydroxyl radical.

Chloramphenicol (CAP), diazepam (DIAZ) and clonazepam (CLONA) have been irradiated in aqueous and methanolic solutions by pulsed electrons (Febetron 707). Spectra of the species formed by the attack of the solvated electron and of OH radical have been determined. The kinetics of reaction of CAP, DIAZ, and CLONA with the solvated electron have been measured. Reactions of radical-radical recombination have also been studied. All these reactions are limited by the diffusion of the reactive species.

Chloramphenicol↗
PubMedDate not supplied

Method to identify products induced by radiosterilization. A study of cefotaxime sodium.

Before the use of radiations to sterilize cefotaxime sodium powder, four new products radioinduced must be identified and qualified. They have an apparent level of or above 0.1%, at the sterilization dose of 25 kGy and are potentially toxic. Their identification is difficult because these products are formed at very low concentrations and generally have a structure similar as that of the main compound. The method proposed is to irradiate the drug in aqueous solution in order to increase the yields in radiolysis products, to compare the retention time of the new products, measured by high performance liquid chromatography, with those obtained after the irradiation of the solid drug and to identify from the aqueous solution the products which are common. One common product was found after the irradiation of cefotaxime in solid state and in aqueous solution. It was easily identified from the irradiated aqueous solution as anticefotaxime. This new product induced by the radiosterilization treatment, is not toxic but less active.

Cefotaxime↗