Characterization and interconversion of polymorphs of premafloxacin, a new quinolone antibiotic.

The quinolone antibiotic premafloxacin crystallizes in at least five solid modifications, including three anhydrous phases (Forms I-III), a hydrate, and a methanolate. The anhydrous phases were studied by optical microscopy, X-ray powder diffraction, HPLC, hot-stage microscopy, dynamic moisture sorption gravimetry, differential scanning calorimetry, thermal gravimetry, and solution and isothermal calorimetry. Dry samples of Form I converted to Form II and ultimately to Form III through a sequence of melts and recrystallizations. Form III was stable to its melting temperature near 200 degrees C. Humidified samples of Form I converted directly to Form III via a moisture-mediated solid-state phase transformation at temperatures as low as 40 degrees C. The calorimetric and solubility data confirmed that Form III was lower in free energy and enthalpy than Form I at room temperature. Our investigation revealed that Form I was not crystallized directly from solution. Rather, Form I was the product of facile solid-state desolvation of the methanol solvate.

A sequential procedure for implementing a computer-based information system.

A sequential procedure is presented for the foodservice manager to follow when considering initial implementation of a computer-based information system (CBIS). A feasibility study is recommended as a first step to analyze the information desired and resources available in order to determine objectives of the proposed CBIS. Alternative CBIS design plans should then be evaluated against critical success factors to determine the direction of initial CBIS efforts. Application software, which provides needed support, then determines the hardware needed. Information about vendors and the suitability of the CBIS to meet needs should be determined next. The following management procedures are suggested: utilization of project management skills, identification of roles for the project team members, and initiation of a phased implementation strategy. Finally, to ensure control of the CBIS project, evaluation and documentation are advised.