External scintigraphy in monitoring the behavior of pharmaceutical formulations in vivo I: technique for acquiring high-resolution images of tablets

A review of emerging technologies enabling improved solid oral dosage form manufacturing and processing

Tablets are the most widely utilized solid oral dosage forms because of the advantages of self-administration, stability, ease of handling, transportation, and good patient compliance. Over time, extensive advances have been made in tableting technology. This review aims to provide an insight about the advances in tablet excipients, manufacturing, analytical techniques and deployment of Quality by Design (QbD). Various excipients offering novel functionalities such as solubility enhancement, super-disintegration, taste masking and drug release modifications have been developed. Furthermore, co-processed multifunctional ready-to-use excipients, particularly for tablet dosage forms, have benefitted manufacturing with shorter processing times. Advances in granulation methods, including moist, thermal adhesion, steam, melt, freeze, foam, reverse wet and pneumatic dry granulation, have been proposed to improve product and process performance. Furthermore, methods for particle engineering including hot melt extrusion, extrusion-spheronization, injection molding, spray drying / congealing, co-precipitation and nanotechnology-based approaches have been employed to produce robust tablet formulations. A wide range of tableting technologies including rapidly disintegrating, matrix, tablet-in-tablet, tablet-in-capsule, multilayer tablets and multiparticulate systems have been developed to achieve customized formulation performance. In addition to conventional invasive characterization methods, novel techniques based on laser, tomography, fluorescence, spectroscopy and acoustic approaches have been developed to assess the physical-mechanical attributes of tablet formulations in a non- or minimally invasive manner. Conventional UV-Visible spectroscopy method has been improved (e.g. fiber-optic probes and UV imaging-based approaches) to efficiently record the dissolution profile of tablet formulations. Numerous modifications in tableting presses have also been made to aid machine product changeover, cleaning, and enhance efficiency and productivity. Various process analytical technologies have been employed to track the formulation properties and critical process parameters. These advances will contribute to a strategy for robust tablet dosage forms with excellent performance attributes.

Radiotelemetric method for evaluating enteric coatings in vivo

A radiotelemetric method for the in vivo evaluation of enteric coating performance is described, and its advantages and disadvantages are compared with those of other available methods. Hydroxypropyl methylcellulose phthalate was used as the test enteric coating. Four dogs were administered several batches of enteric-coated tablets containing buffers. Tablet disintegration was determined by radiotelemetric detection of the pH drop in the upper intestine due to release of the buffer. Premature rupture of the coating in the stomach was detected by a rise and then a fall in gastric pH prior to gastric emptying. The average gastric emptying time was 80 +/- 18 min (SEM), while the average time for a tablet to disintegrate in the upper intestine was 14.2 +/- 2 min. The average disintegration time was not affected by a change in the batch (for a given tablet core pH) or the dog used, suggesting that the method yielded readily reproducible results. Although there was little correlation with in vitro disintegration times, the method gave results similar to those reported in the literature for the same enteric coating in a human study. Of the formulations tested, it was concluded that buffering the core to pH 4 was most suitable for studying enteric coating performance.