High-resolution solid-state carbon-13 nuclear magnetic resonance spectra of mofebutazone, phenylbutazone, and oxyphenbutazone in relation to X-ray crystallographic data.

The solid-state 13C NMR spectra of mofebutazone, phenylbutazone, and oxyphenbutazone monohydrate and anhydrate are presented. The crystal structures of these pyrazolidinedione derivatives, obtained by single-crystal X-ray analysis, were previously reported, revealing distinct differences in crystal structure. In this report, the chemical shift values observed for the solid-state 13C spectra are related to the chemical environment of the various carbon atoms and compared with the crystallographic data. Results indicate that solid-state NMR spectroscopy is potentially useful in the study of drugs in the solid state.

Oxytetracyline tablet formulations: effect of variations in binder concentration and volume on granule and tablet properties.

Formulation studies have been conducted on an oxytetracycline dihydrate tablet formulation containing microcrystalline cellulose and alginic acid, wet granulated with polyvinylpyrrolidone (PVP) solution. A range of granule properties including size, strength packing and porosity, and tablet properties including breaking load, porosity, disintegration and dissolution have been measured. Increased compaction pressure decreased tablet porosity. The reproducibility of the above properties was determined by tests on nine standard batches of granules and tablets. An increased concentration of PVP in the binder solution decreased the rate of tablet dissolution. Although the volume of granulating solution apparently controlled the granule size, it did not significantly alter the tablet dissolution, when the amount of PVP was constant.

Oxytetracycline tablet formulations: the influence of excipients and the method of granulation.

The proportion of microcrystalline cellulose and alginic acid present as excipients in the dry mix for an oxytetracycline dihydrate tablet formulation, prepared by a conventional wet granulation process, has been shown to influence granule formation and properties. Granule size distributions have varied widely due perhaps to variation in binder distribution. Granulating with water was equally satisfactory to granulating with a PVP solution. Slugged granules produced robust tablets, which disintegrated and dissolved rapidly.

Oxytetracycline tablet formulations: the effect of wet mixing time, particle size and batch variation on granule and tablet properties.

The wet mixing time has been shown to influence the properties of an oxytetracycline dihydrate tablet formulation, wet granulated with PVP solution. Increased time of wet mixing produced larger, stronger and more dense granules, which compressed into tablets with longer disintegration and dissolution times. Decreased drug particle size aggravated these trends. A decrease in drug particle size also produced larger, stronger and more dense granules. Above an oxytetracycline mean particle diameter of about 6 mum, the tablet dissolution was satisfactory. As the oxytetracycline particle size was decreased further, however, the distintegration and dissolution of the corresponding tablets was markedly slower.