PubMed · 5657684
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A J Nespole. 1968. Ampicillin dosage.. https://pubmed.ncbi.nlm.nih.gov/5657684/
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The identification of anhydrous and hydrated forms of pharmaceutical substances is of great importance in pharmaceutical science and industry. We report the use of THz time-domain spectroscopy (THz-TDS) for pseudopolymorph investigation. The anhydrous forms of pharmaceutical substances including caffeine, theophylline, D-glucose, and ampicillin exhibit different THz absorption spectra from their hydrated forms, presumably due to their different intermolecular vibrational modes mediated by hydrogen-bonding. The data from X-ray powder diffractometry (XRPD) confirm the crystallinity differences between the anhydrous and hydrated forms. The temperature-dependent THz spectra of caffeine hydrate were also recorded, and it demonstrates that THz-TDS can be used to monitor the dehydration process of drug hydrates. We conclude that THz-TDS is an advantageous technique for the pseudopolymorph identification and study, and has great potential to become a process analytical technology (PAT) in pharmaceutical production and quality control.
The purpose of this study was using a developed microfluidic chip to prepare size-controlled monodisperse chitosan microparticles encapsulating ampicillin. Our strategy is that a chitosan aqueous solution (the disperse phase) is fed into the microfluidic chip equipped with a cross-junction microchannel, and is sheared by the viscous oil flows (the continuous phase) to form monodisperse semi-product, chitosan emulsions. These fine emulsions are then gelled into stability upon gelation by injection of copper sulfate solution at the terminal microchannel of the microfluidic chip, and finally the uniform chitosan microparticles are formed in an efficient manner. The proposed chip is fabricated by a CO(2) laser machine on a conventional poly methyl methacrylate (PMMA) substrate. This microfluidic chip has four inlet ports, one cross-channel and one outlet port. We have demonstrated that one can control the size of chitosan microparticles from 100 to 800 microm in diameter (with a variation less than 5%) by altering the relative sheath/sample flow rate ratio. Experimental data showed that when given a steady continuous phase (oil flow), the emulsion size increases with the increase in average velocity of the dispersed phase flow (sample flow). In addition, the release of the model drug (ampicillin) from these microspheres is proved to be once-daily for clinical application. We also revealed that appropriate particle sizes for different release patterns are predictable, enabling better applications of chitosan as a drug carrier.
The prevalence of CTX-M-producing members of the Enterobacteriaceae is increasing worldwide. A novel, multiplex, real-time TaqMan PCR assay to detect and type bla(CTX-M) genes is described which is an improvement on previously described techniques with respect to reduced assay time, elimination of the need for protracted post-PCR processing and the convenience of a single reaction vessel. Based on beta-lactam antibiogram and MIC data, 478 of 1279 Enterobacteriaceae isolates from clinical blood and urine culture specimens were selected and tested for extended-spectrum beta-lactamase (ESBL) production using phenotypic methods. The new TaqMan assay detected and typed bla(CTX-M) genes in 21 of 28 ESBL-producing isolates.