PubMed · 13571728
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1958. [Erythromycin].. https://pubmed.ncbi.nlm.nih.gov/13571728/
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OBJECTIVE: Determine if erythromycin is an effective agent for achieving occlusion of the Fallopian tube for nonsurgical female sterilization. METHODS: Two studies of 100 healthy volunteers requesting sterilization were planned, one in Julpia Andhermanik and the other in Kolkata (Calcutta). A readily available marketed tablet preparation containing 500 mg of the estolate salt of erythromycin was used for the trial. In one study (Bishnupur), the tablet was crushed before placing in a copper-T IUD inserter for placement at the fundus. In the other study (Kolkata), crushed tablets were processed into 50 mg pellets of the same diameter as standard quinacrine pellets and 10 pellets were inserted at the fundus using aseptic precautions. Procedures in each study were repeated at 30 days. Oral contraceptives were prescribed for three cycles following first insertion. No incentive was offered for participation in the trial. Follow-up treatment, including first-trimester abortion for pregnancy due to failure of the sterilization procedure, was assured without charge. Due to extraordinary patient demand, one study (Bishnupur) was expanded to 690 cases for reasons of compassion. RESULTS: At 12 months of use, the failure rate of the sterilization procedure for the crushed 500 mg tablets was 35.8% (SE = 1.8) with 417 women at risk. At 12 months of use, the failure rate for the erythromycin pellets was 28.6% (SE = 5.0) with 43 women at risk. There were no serious complications reported in either trial. All pregnancies resulting from failure of the sterilization procedure were terminated by menstrual regulation within 10 weeks gestation. CONCLUSIONS: The failure rate in this study is unacceptably high for erythromycin to be used as a sterilization method.
Spot size reduction and increased detection sensitivity in matrix-assisted laser desorption/ionisation (MALDI) of small molecules are accomplished by using an inexpensive and removable hydrophobic coating for MALDI targets, based on 3M Scotch Gard surface treatment. Several variations in sample preparation were explored, such as surface coating technique, identity of the matrix, solvent composition, and the type of metal support plate used. These were investigated on both uncoated and coated surfaces and their impact on spot size, crystal coverage, and sensitivity is presented here. Additionally, crystallisation behaviour obtained on coated plates is compared with that on uncoated plates using scanning electron microscope analysis. To demonstrate the potential of the new coating technique, erythromycin A and valinomycin are studied to determine the increase in detection sensitivity of coated plates in comparison to uncoated plates, and to reveal the suitability of the plates for application in combined high-performance liquid chromatography/MALDI (HPLC/MALDI), where widely varying solvent compositions and droplet volumes are observed. It is shown that enhancements in detection sensitivities correlate very well with the achieved spot size reduction. The versatility of the coated plates is also exhibited by the ease of removing the surface layer, after which the plates can be rigorously cleaned without worry about damaging the hydrophobic surface, followed by a quick reapplication of new hydrophobic coating material. This makes the non-polar coating superior to more expensive commercial hydrophobic-coated targets, which are much more delicate to clean. Furthermore, cleaning and reapplication eliminate potential carry-over effects and the easy application procedure also makes the fabrication of inexpensive, disposable MALDI targets readily possible.
Chemical shift modeling, utilizing the DFT B3LYP/D95** method, provides the spectral assignment of the 35 visible 13C resonances from the solid-phase erythromycin A dihydrate. A new resonance at 110.8ppm is observed in the high-resolution 13C CP/MAS spectrum upon the application of heat or sample desiccation. With the use of the dipolar-dephasing spectral editing technique, this resonance is identified as a hemiketal carbon and the alternative hypothesis, a conformational change to the anomeric carbon of the desosamine sugar, is ruled out. Hence, the formation of a cyclic hemiketal in erythromycin A while in the solid phase is proven by solid-state NMR. The principal components of the 13C chemical-shift tensor corresponding to this hemiketal are reported. This is the first measurement of hemiketal 13C principal values. The delta11 and delta22 components are unique compared to anomeric carbon values reported in the literature.