An evaluation of the adhesion of solid oral dosage form coatings to the oesophagus

Abstract

There is a requirement for the development of oral dosage forms that are adhesive and allow extended oesophageal residence time for localised therapies, or are non-adhesive for ease of 15 swallowing. This study provides an initial assessment of the in vitro oesophageal retention characteristics of several widely utilised pharmaceutical coating materials. To this end, a previously described apparatus has been used to measure the force required to pull a coated disc-shaped model tablet across a section of excised oesophageal tissue. Of the materials tested, the well-studied mucoadhesive polymer sodium alginate was found to be associated with significant oesophageal 20 adhesion properties that was capable of 'self-repairing'. Hydroxypropylmethylcellulose exhibited less pronounced bioadhesive behaviour and blending this with plasticiser or with low molecular weight polymers and surfactants did not significantly affect this. Low molecular weight water soluble polymers, were found to behave similarly to the uncoated glass control disc. Polysorbates exhibited bioadhesion behaviour that was majorly influenced by the nature of the surfactant. The insoluble 25 polymer ethylcellulose, and the relatively lipophilic surfactant sorbitan monooleate were seen to move more readily than the uncoated disc, suggesting that these may have a role as 'easy-toswallow' coatings.

Developing methodology to evaluate the oral sensory features of pharmaceutical tablet coatings

“…In addition, on hydration they form a slippery layer that further reduces friction. This hypothesis is supported by a study showing how coatings improved the ease of swallowing in vitro, where coated discs with lubricating properties needed a reduced force to be moved across ex vivo porcine oesophageal tissue (Smart et al, 2015).…”

Better Medicines for Older Patients: Considerations between Patient Characteristics and Solid Oral Dosage Form Designs to Improve Swallowing Experience

“…New non-mucoadhesive film coating materials that exhibit enhanced gliding performance throughout the oro-esophageal system are still required to address this [157][158][159].…”

A review of the approaches to predict the ease of swallowing and post-swallow residues

“…Further relevant studies considered the mucoadhesion in the esophagus for pharmacology and tablet design. In vitro experiments 320 have been set up to quantify adhesion and detachment force of tablets against a simplified model of esophageal mucosa lined with artificial saliva (Smart et al, 2015). The esophageal mucosa is supported onto a sub frame of two layers of muscle orderly disposed in circular (skeletal musculature) and longitudinal (smooth or visceral musculature) pattern.…”

“…Few studies aimed at understanding how tablet shape and surface coating affect esophageal transit time and adhesion. In vivo models of esophageal mucosa have recently been 950 proposed (Cook and Khutoryanskiy, 2015;Smart et al, 2015), but results so far have not considered the relevant challenges of drug therapy in dysphagic patients, such as the effect of co-administration with thickened liquids, nor how the physical alteration of capsules and tablets influence their residence time in the esophagus. The organ can elongate and bend due to the differential stresses generated at the interface of upon inflation of embedded sets of air chambers (Lu et al, 2017).…”