Solid-State Stability Testing of Drugs by Isothermal Calorimetry
A new technique has been developed to calculate rapidly the solid-state room-temperature degradation rate of drugs and drug candidates. The technique utilizes measurements of the initial rate of heat output at several elevated temperatures by isothermal calorimetry and the degradation rate of the compound determined at a single elevated temperature by chromatography. The activation energies and degradation rates at 25°C calculated by conventional methods and by isothermal calorimetry are compared and discussed. The compounds studied were phenytoin, triamterene, digoxin, tetracycline, theophylline, diltiazem, and several proprietary ICI compounds.
Physical Characterization of Pharmaceutical Formulations in Frozen and Freeze-Dried Solid States: Techniques and Applications in Freeze-Drying Development
Physical characterization of formulations in frozen and freeze-dried solid states provides indispensable information for rational development of freeze-dried pharmaceutical products. This article provides an overview of the physical characteristics of formulations in frozen and freeze-dried solid states, which are essential to both formulation and process development. Along with a brief description of techniques often used in physical characterization for freeze-drying development, applications of and recent improvements to these techniques are discussed. While most of these techniques are used conventionally in physical characterization of pharmaceuticals, some techniques were designed or modified specifically for studies in freeze-drying. These include freeze-drying microscopy, freeze-drying X-ray powder diffractometry and cryoenvironmental scanning microscopy, which can be used to characterize the physical properties of the formulation under conditions similar to the real vial lyophilization process. Novel applications of some conventional techniques, such as microcalorimetry and near infrared (NIR) spectroscopy, which facilitated freeze-drying development, receive special attention. Research and developmental needs in the area of physical characterization for freeze-drying are also addressed, particularly the need for a better understanding of the quantitative correlation between the molecular mobility and the storage stability (shelf life).
Development of Science and Technology in the Iranian Electric Power Industry: Challenges and Future Progress
This chapter examines four key segments of the electric power industry in Iran: generation, transportation, distribution and consumption. It reviews the method, development, and evolution of electric power generation in the country. Specifically, the chapter reviews the structure of the electric industry, the main players, institutions, standards as well as laws, human resources, technology, the export and import markets, and engineering management of the industry in the country. Finally, the challenges facing the industry will be identified and policy suggestions to remedy the problems will be provided.