Quantification of three macrolide antibiotics in pharmaceutical lots by HPLC: Development, validation and application to a simultaneous separation

A new validated high performance liquid chromatographic (HPLC) method with rapid analysis time and high efficiency, for the analysis of erythromycin, azithromycin and spiramycin, under isocratic conditions with ODB RP18 as a stationary phase is described. Using an eluent composed of acetonitrile –2-methyl-2-propanol –hydrogenphosphate buffer, pH 6.5, with 1.5% triethylamine (33:7: up to 100, v/v/v), delivered at a flow-rate of 1.0 mL min-1. Ultra Violet (UV) detection is performed at 210 nm. The selectivity is satisfactory enough and no problematic interfering peaks are observed. The procedure is quantitatively characterized and repeatability, linearity, detection and quantification limits are very satisfactory. The method is applied successfully for the assay of the studied drugs in pharmaceutical dosage forms as tablets and powder for oral suspension. Recovery experiments revealed recovery of 97.13–100.28%

Production of polyclonal antibodies directed to recombinant methionyl bovine somatotropin

The administration of recombinant methionyl bovine somatotropin (rMbST) to dairy cows to increase milk yield remains a common practice in many countries including the USA, Brazil, Mexico, South Africa and Korea, whereas it has been forbidden within the European Union (EU) since 1999. A rapid screening immunoanalytical method capable of the unequivocal determination of rMbST in milk would be highly desirable in order to effectively monitor compliance with the EU-wide ban for home-made or imported dairy products. For decades, the production of specific antibodies for this recombinant isoform of bovine somatotropin (bST) has remained elusive, due to the high degree of sequence homology between both counterparts (e.g. methionine for rMbST in substitution of alanine in bST at the N-terminus). In this study, we compared several immunizing strategies for the production of specific polyclonal antibodies (pAbs), based on the use of the full-length recombinant protein, an rMbST N-terminus peptide fragment and a multiple antigen peptide (MAP) which consists of an oligomeric branching lysine core attached to the first two N-terminus amino acids of rMbST, methionine and phenylalanine (MF-MAP). The immunization with KLH-conjugated MF-MAP led to the production of the pAb with the highest rMbST/bST recognition ratio amongst the generated battery of antibodies. The pAb exhibited a specific binding ability to rMbST in a competitive antigen-coated ELISA format, which avidity was further improved after purification by rMbST N-terminus peptide-based affinity chromatography. These results suggest that immunodiscrimination between structurally related proteins can be achieved using immuno-enhanced immunogens such as MAPs

Cystic dilation of the distal end of the nasolacrimal duct: underrated cause of epiphora in adults and its endoscopic treatment.

Epiphora is a frequent reason for ophthalmologic consultation. Among the multiple causes, obstructions of the lacrimal excretory system are common. Sacal and postsacal obstructions are much more frequent than presacal obstructions. Obstruction at the level of the Hasner's valve is rare and likely underestimated. The authors report the clinical history and the imaging of 3 patients with a cystic dilation of the distal end of the nasolacrimal duct (NLD). These patients were easily managed by an ENT surgeon. In one case, the surgery consisted of an endonasal DCR where in the 2 other cases, a marsupialisation of the cystic expansion of the nasolacrimal duct was successfully performed with the micro- debrider. The authors review the world literature on this specific topic. They conclude that a coronal sinus CT scan and an inferior meatus endoscopy should be included in the ophthalmologic work-up performed in all cases of low obstruction of the lacrimal system. When there is a dilation of the distal end of the NLD the marsupialisation of the cystic expansion in the inferior meatus is the option of treatment instead of performing a DCR. ENTs must play a role in the assessment and treatment of low obstructions of the lacrimal excretory system