Pharmaceutical Research

, Volume 34, Issue 4, pp 687–695 | Cite as

Using the Slug Mucosal Irritation Assay to Investigate the Tolerability of Tablet Excipients on Human Skin in the Context of the Use of a Nipple Shield Delivery System

  • Richard Kendall
  • Joke Lenoir
  • Stephen Gerrard
  • Rebekah L. Scheuerle
  • Nigel K. H. Slater
  • Catherine Tuleu
Research Paper



Neonates are particularly challenging to treat. A novel patented drug delivery device containing a rapidly disintegrating tablet held within a modified nipple shield (NSDS) was designed to deliver medication to infants during breastfeeding. However concerns exist around dermatological nipple tolerability with no pharmaceutical safety assessment guidance to study local tissue tolerance of the nipple and the areola. This is the first Slug Mucosal Irritation (SMI) study to evaluate irritancy potential of GRAS excipients commonly used to manufacture rapidly disintegrating immediate release solid oral dosage form


Zinc sulphate selected as the antidiarrheal model drug that reduces infant mortality, was blended with functional excipients at traditional levels [microcrystalline cellulose, sodium starch glycolate, croscarmellose sodium, magnesium stearate]. Slugs were exposed to blends slurried in human breast milk to assess their stinging, itching or burning potential, using objective values such as mucus production to categorize irritation potency


Presently an in vivo assay, previously validated for prediction of ocular and nasal irritation, was used as an alternative to vertebrate models to anticipate the potential maternal dermatological tolerability issues to NSDS tablet components. The excipients did not elicit irritancy. However, mild irritancy was observed when zinc sulphate was present in blends.


These promising good tolerability results support the continued investigation of these excipients within NSDS rapidly disintegrating tablet formulations. Topical local tolerance effects being almost entirely limited to irritation, the slug assay potentially adds to the existing preformulation toolbox, and may sit in between the in vitro and existing in vivo assays.


nipple shield delivery system pediatric skin tolerability slug mucosal irritation assay tablet excipients 



Active pharmaceutical ingredient


Benzalkonium chloride


Contact period


Generally recognised as safe


Human breast milk


Human immunodeficiency virus


Human T-lymphotropic virus


Mucus production


Negative control


Nipple shield delivery system


Phosphate buffered saline


Positive control


Research ethics committee


Stinging, itching or burning


Slug mucosal irritation



This work was made possible through the support of the Saving Lives at Birth partners: the United States Agency for International Development (USAID), the Government of Norway, the Bill & Melinda Gates Foundation, Grand Challenges Canada, and the UK Department for International Development (DFID). Additional support was provided by the Gates Cambridge Trust.

Many thanks go to Gillian Weaver, manager of the Queen Charlotte’s and Chelsea Hospital Milk Bank (Imperial College Healthcare NHS Trust) for coordinating access to the HBM samples. These samples were provided by the Imperial College Healthcare NHS Trust Tissue Bank. Other investigators may have received samples from these same tissues. The research was supported by the National Institute for Health Research (NIHR) Biomedical Research Centre based at Imperial College Healthcare NHS Trust and Imperial College London. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.

Stephen Gerrard is an inventor of the nipple shield delivery system (US patent 8357117 B2. See


  1. 1.
    Samardzic J, Turner MA, Bax R, Allegaert K. Neonatal medicines research: challenges and opportunities. Expert Opin Drug Metab Toxicol. 2015;11(7):1041–52.CrossRefPubMedGoogle Scholar
  2. 2.
    Beggs SA, Cranswick NE, Reed MD. Improving drug use for children in the developing world. Arch Dis Child. 2005;90(10):1091–3.CrossRefPubMedPubMedCentralGoogle Scholar
  3. 3.
    UNICEF, WHO. Sources and prices of selected medicines for children. Including therapeutic food, dietary vitamin and mineral supplementation. 2nd ed (2010). Available from Accessed 2016 June 27.
  4. 4.
    WHO. Promoting safety of medicines for children. 2007. Available from: Accessed 2016 June 27.
  5. 5.
    Walsh J, Cram A, Woertz K, Breitkreutz J, Winzenburg G, Turner R, et al. Playing hide and seek with poorly tasting paediatric medicines: do not forget the excipients. Adv Drug Deliv Rev. 2014;73:14–33.CrossRefPubMedGoogle Scholar
  6. 6.
    Pandolfini C, Bonati M. A literature review on off-label drug use in children. Eur J Pediatr. 2005;164(9):552–8.CrossRefPubMedGoogle Scholar
  7. 7.
    Stoltenberg I, Winzenburg G, Breitkreutz J. Solid oral dosage forms for children–formulations, excipients and acceptance issues. J Appl Ther Res. 2010;7:141–6.Google Scholar
  8. 8.
    WHO, Revised WHO Classification and Treatment of Pneumonia in Children at Health Facilities: Evidence Summaries. (2014). Available from: Accessed 2016 June 27.
  9. 9.
    WHO. Diarrhoeal disease. Fact sheet N°330, April 2013 2016 Accessed June 27. Available from:
  10. 10.
    Soulele K, Macheras P. Milk as a medium for pediatric formulations: experimental findings and regulatory aspects. Int J Pharm. 2015;492(1–2):344–5.CrossRefPubMedGoogle Scholar
  11. 11.
    Orubu S, Hobson NJ, Basit AW, Tuleu C. The Milky Way: paediatric milk-based dispersible tablets prepared by direct compression – a proof-of-concept study. J Pharm Pharmacol. 2016 In press.Google Scholar
  12. 12.
    Gerrard SE, Orlu‐Gul M, Tuleu C, Slater NK. Modelling the physiological factors that affect drug delivery from a nipple shield delivery system to breastfeeding infants. J Pharm Sci. 2013;102(10):3773–83.CrossRefPubMedGoogle Scholar
  13. 13.
    Gerrard SE, Baniecki ML, Sokal D, Morris MK, Urdaneta-Hartmann S, Krebs F, Wigdahl B, Abrams BF, Hanson CV, Slater NKH, Edwards A. A nipple shield delivery system for oral drug delivery to breastfeeding infants: microbicide delivery to inactivate HIV. 2012;434(1–2):224–34.Google Scholar
  14. 14.
    Hart CW, Israel-Ballard KA, Joanis CL, Baniecki ML, Thungu F, Gerrard SE, et al. Acceptability of a nipple shield delivery system administering antiviral agents to prevent mother-to-child transmission of HIV through breastfeeding. J Hum Lact. 2015;31:68–75.CrossRefPubMedGoogle Scholar
  15. 15.
    Etheridge E. Letter to the editor regarding “acceptability of a nipple shield delivery system administering antiviral agents to prevent mother-to-child transmission of HIV through breastfeeding”. J Hum Lact. 2015;31:671.CrossRefPubMedGoogle Scholar
  16. 16.
    Hart CW, Israel-Ballard KA, Joanis CL, Baniecki ML, Thungu F, Gerrard SE, et al. Response to letter to the editor regarding “acceptability of a nipple shield delivery system administering antiviral agents to prevent mother-to-child transmission of HIV through breastfeeding”. J Hum Lact. 2015;31:672–4.CrossRefPubMedGoogle Scholar
  17. 17.
    WHO. Global Health Observatory (GHO) data on Under-five. (2015). Available from 2016 June 27.
  18. 18.
    Emmett PM, Rogers IS. Properties of human milk and their relationship with maternal nutrition. Early Hum Dev. 1997;49:S7–28.CrossRefPubMedGoogle Scholar
  19. 19.
    Adriaens E, Bytheway H, De Wever B, Eschrich D, Guest R, Hansen E, et al. Successful prevalidation of the slug mucosal irritation test to assess the eye irritation potency of chemicals. Toxicol in Vitro. 2008;22(5):1285–96.CrossRefPubMedGoogle Scholar
  20. 20.
    Adriaens E, Remon JP. Gastropods as an evaluation tool for screening the irritating potency of absorption enhancers and drugs. Pharm Res. 1999;16:1240–4.CrossRefPubMedGoogle Scholar
  21. 21.
    Adriaens E, Dierckens K, Bauters TG, Nelis HJ, Van Goethem F, Vanparys P, et al. The mucosal toxicity of different benzalkonium chloride analogues evaluated with an alternative test using slugs. Pharm Res. 2001;18(7):937–42.CrossRefPubMedGoogle Scholar
  22. 22.
    Adriaens E, Ameye D, Dhondt MM, Foreman P, Remon JP. Evaluation of the mucosal irritation potency of co-spray dried Amioca®/poly (acrylic acid) and Amioca®/Carbopol® 974P mixtures. J Control Release. 2003;88(3):393–9.CrossRefPubMedGoogle Scholar
  23. 23.
    Callens C, Adriaens E, Dierckens K, Remon JP. Toxicological evaluation of a bioadhesive nasal powder containing a starch and Carbopol® 974 P on rabbit nasal mucosa and slug mucosa. J Control Release. 2001;76(1):81–91.CrossRefPubMedGoogle Scholar
  24. 24.
    Ceulemans J, Vermeire A, Adriaens E, Remon JP, Ludwig A. Evaluation of a mucoadhesive tablet for ocular use. J Control Release. 2001;77(3):333–44.CrossRefPubMedGoogle Scholar
  25. 25.
    Dhondt MM, Adriaens E, Remon JP. The evaluation of the local tolerance of vaginal formulations, with or without nonoxynol-9, using the slug mucosal irritation test. Sex Transm Dis. 2004;31(4):229–35.CrossRefPubMedGoogle Scholar
  26. 26.
    Dhondt MM, Adriaens E, Roey JV, Remon JP. The evaluation of the local tolerance of vaginal formulations containing dapivirine using the Slug Mucosal Irritation test and the rabbit vaginal irritation test. Eur J Pharm Biopharm. 2005;60(3):419–25.CrossRefPubMedGoogle Scholar
  27. 27.
    Weyenberg W, Vermeire A, Dhondt MM, Adriaens E, Kestelyn P, Remon JP, et al. Ocular bioerodible minitablets as strategy for the management of microbial keratitis. Invest Ophthalmol Vis Sci. 2004;45(9):3229–33.CrossRefPubMedGoogle Scholar
  28. 28.
    Draize JH, Woodard G, Calvery HO. Methods for the study of irritation and toxicity of substances applied topically to the skin and mucous membranes. J Pharmacol Exp Ther. 1944;82(3):377–90.Google Scholar
  29. 29.
    Lenoir J, Adriaens E, Remon JP. New aspects of the Slug Mucosal Irritation assay: predicting nasal stinging, itching and burning sensations. J Appl Toxicol. 2011;31(7):640–8.CrossRefPubMedGoogle Scholar
  30. 30.
    Lenoir J, Claerhout I, Kestelyn P, Klomp A, Remon JP, Adriaens E. The slug mucosal irritation (SMI) assay: development of a screening tool for the evaluation of ocular discomfort caused by shampoos. Toxicol in Vitro. 2011;25(8):1919–25.CrossRefPubMedGoogle Scholar
  31. 31.
    Boone C, Bond C, Buhl K, Stone D.. Zinc Sulfate General Fact Sheet; National Pesticide Information Center, Oregon State University Extension Services. (2012). Available from: Last Accessed 2016 June 27.
  32. 32.
    Schüder I, Port G, Bennison J. Barriers, repellents and antifeedants for slug and snail control. Crop Prot. 2003;22(8):1033–8.CrossRefGoogle Scholar
  33. 33.
    Marigomez JA, Angulo E, Saez V. Feeding and growth response to copper, zinc, mercury and lead in the terrestrial gastropod Arionater (Linne). J Molluscan Stud. 1986;52(1):68–78.CrossRefGoogle Scholar
  34. 34.
    Geddes DT, Kent JC, Mitoulas LR, Hartmann PE. Tongue movement and intra-oral vacuum in breastfeeding infants. Early Hum Dev. 2008;84(7):471–7.CrossRefPubMedGoogle Scholar
  35. 35.
    Kent JC, Mitoulas LR, Cregan MD, Ramsay DT, Doherty DA, Hartmann PE. Volume and frequency of breastfeedings and fat content of breast milk throughout the day. Pediatrics. 2006;117(3):e387–95.CrossRefPubMedGoogle Scholar
  36. 36.
    Prieto CR, Cárdenas H, Salvatierra AM, Boza C, Montes CG, Croxatto HB. Sucking pressure and its relationship to milk transfer during breastfeeding in humans. J Reprod Fertil. 1996;108(1):69–74.CrossRefPubMedGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2017

Authors and Affiliations

  1. 1.School of PharmacyUniversity College LondonLondonUK
  2. 2.Faculty of Pharmaceutical SciencesUniversity of GhentGhentBelgium
  3. 3.Department of Chemical Engineering and BiotechnologyUniversity of CambridgeCambridgeUK

Personalised recommendations