ABSTRACT
To support the introduction of novel, controlled release dosage forms, regulatory bodies have increasingly accepted imaging technologies to validate proof of the concept over the past 10 years. Of all the modalities available, i.e., x-rays, nuclear medicine (gamma scintigraphy and positron emission tomography), magnetic resonance imaging, and ultrasound, gamma scintig raphy has become preeminent as a tool in the assessment of oral, pulmonary, and ophthalmic dosage forms. Many of the early applications in the study of controlled release dosage forms rode on the developments in diagnostic radiopharmaceuticals, which have steadily improved in terms of specificity, safety, and diversity. Advances in technology have allowed faster acquisi tion, and new computing techniques have allowed better characterization, of the pharmacoki netics of the radiopharmaceuticals incorporated in the formulation. Parallel to this, applications of scintigraphy in the study of drug formulations generated a new expertise quite separate from the diagnostic arena. Now radiology and nuclear medicine are utilizing this knowledge to ob tain better imaging agents and in many respects the two paths criss-cross to the mutual benefit of both camps.
