Physiological Pharmaceutics

Oesophageal transit 69Figure 4.8 Location of twenty five drug induced ulcers, (scale on the left hand sideindicates distance of the lesions from the teeth 29 )Impaired swallowing in the elderly will result in even small tablets (4 mm) adheringto the oesophagus 31 . Low dose tablets, including the aminobisphosphonates used to inhibitbone resorption, have been reported to cause ulceration 32 . This has led to a FDArecommendation that these medications be consumed with 240 ml water, the subject toremain erect for 30 minutes after administration. Dosage forms which float on the coadministeredwater may also present problems to the elderly by sticking to the roof of theoropharynx.PATIENT PREFERENCE AND EASE OF SWALLOWINGPatients prefer taking capsules to large oval or round tablets, partly due to the smoothsurface and the shape which assists swallowing. The difficulty in swallowing large roundtablets increases over the age of 60 years when up to 60% of healthy subjects may reporta problem. There is a tendency amongst these patients to chew the tablets and capsules orto open the capsule and disperse the pellets in food or a drink. This can lead to an unknownloss of a proportion of the dose. Chewing formulations will destroy the integrity of anysurface coating and it is a particular problem for sustained or controlled releaseformulations that are designed to be swallowed intact. Chewing will destroy matrixstructures and increase the surface area available for drug dissolution.EFFECT OF DISEASED STATES ON TRANSITOesophageal transit may be influenced by diseased states such as oropharyngeal dysphagiaor achalasia. Oral pharyngeal dysphagia is a common problem particularly in the elderlywhich carries a significant morbidity and mortality 33 . Oral-pharyngeal dysphagia copuld be