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Original research
Administration of aspirin tablets using a novel gel-based swallowing aid: an open-label randomised controlled cross-over trial
  1. David John Wright1,
  2. John F Potter2,
  3. Allan Clark2,
  4. Annie Blyth2,
  5. Vivienne Maskrey2,
  6. Giovanna Mencarelli3,
  7. Sarah O Wicks4,
  8. Duncan Q M Craig5
  1. 1 Pharmacy, University of East Anglia, Norwich, UK
  2. 2 Medicine, University of East Anglia, Norwich, UK
  3. 3 University of Bath, Bath, UK
  4. 4 Department of Pharmacy, Health and Well-Being, University of Sunderland, Sunderland, UK
  5. 5 School of Pharmacy, University College London, London, UK
  1. Correspondence to David John Wright, Pharmacy, University of East Anglia, Norwich NR4 7TJ, UK; d.j.wright{at}


Introduction To ease administration of medicines to people with dysphagia we developed and patented a gel formulation within which whole tablets could be inserted. The aim was to determine whether the gel would affect bioequivalence of uncoated aspirin tablet.

Method A gel containing gelatin, hydroxypropylmethylcellulose, citric acid, potassium sorbate and water was developed to maintain structure on tablet insertion and increase saliva production to lubricate the swallow.

In an open-label cross-over trial 12 healthy male volunteers were administered a 300 mg uncoated aspirin tablet with and without gel with a 7-day washout period. Blood salicylate levels, platelet activity and patient satisfaction were measured over 2 hours. Analysis was based on a random effects cross-over model.

Results The estimated mean ratio (90% CI) of effect on salicylate levels when comparing administration with and without gel was 0.77 (90% CI 0.40 to 1.47) for amount absorbed and 0.76 (90% CI 0.44 to 1.31) and on total ASP-arachidonic acid platelet activity 1.16 (90% CI 0.88 to 1.53) and maximum ASP-arachidonic platelet activity 0.98 (90% CI 0.79 to 1.22). These results are outside of the range allowable for the assumption of bioequivalence. Participants rated the taste of aspirin tablets significantly better when encapsulated in the gel (p<0.05).

Discussion We cannot assume that uncoated aspirin administration with and without gel is bioequivalent. Administration with gel resulted in reduced salicylate levels and therefore increased platelet function. Further research is required to determine the exact reason for this result. The results bring into question current processes for providing marketing authorisation for medical devices which are designed to aid swallowing.

  • dysphagia
  • swallowing aid
  • bioequivalence
  • aspirin
  • salicylate levels
  • platelet function

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  • Contributors DJW and DQMC originated the idea for the gel, were coapplicants for the MRC funding and were responsible for managing the project. GM and SOW were responsible for gel development and testing in vitro. AB and VM were responsible for gel testing in vivo. AC provided statistical input at all stages of the study. AB, VM, SOW, DJW and JFP were responsible for development of the clinical trial protocol and JFP was the principal investigator responsible for management of the trial at the site. All authors contributed to the writing of the article and provided feedback on the different iterations.

  • Funding The study was funded by the Medical Research Council ‘Developmental Pathway Funding Scheme’ (grant reference: G902184).

  • Competing interests DJW undertakes consultancy work for and currently holds a research grant from Rosemont Pharmaceuticals who manufactures liquid medicines.

  • Patient consent for publication Not required

  • Ethics approval MHRA Device (CI/2012/0030 SMART Swallowing Aid) and NHS Research Ethics Committee approvals (Cambridge Central NRES Committee, East of England 14/EE/0156) were obtained prior to commencement of the study.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement Data are available upon reasonable request.

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