Evaluation of local tolerance of a plant extract by the slug mucosal irritation (SMI) assay

This article describes the performance of a laboratory exercise, the Slug Mucosal Irritation (SMI) assay, carried out by third year undergraduate students, to investigate the local tolerance of an ethanolic plant extract. The plant extract, Spilanthes acmella, contains various bio-active compounds, such as the N-alkylamide spilanthol. After administration of the plant extract to the slugs, they were observed for possible discomfort and tissue damage. When slugs are exposed to a substance with irritant properties, the mucus production of the slugs will increase. Furthermore, slugs will release proteins, including enzymes, when tissue damage occurs. This laboratory experiment is a practically feasible in vivo test using slugs which are invertebrates that are not protected by the legislation on animal testing. Students were supervised by lab instructors who encouraged students to actively contribute in their groups, to think about the experimental design of the laboratory test, and to facilitate scientific discussions, but the majority of the ideas had to come from the students themselves. Hence, this biomedical in vivo experiment offered a great opportunity for students to learn to work in group, to critically interpret and report their results, to gain knowledge about the subject, and to communicate and discuss with other students as well as with the lab instructors. Furthermore, this experiment teaches students current toxicological methodologies encompassing principles and their application of biochemistry, analytical chemistry, toxicology, animal experimentation and data handling. This way of interdisciplinary teaching is especially important for last year undergraduate students, as this is a good preparation for the Masters dissertation. At the end of the laboratory exercise, students received a questionnaire and most of the students indicated that they gained valuable knowledge and skills. This laboratory exercise can be incorporated into chemical, biological, pharmaceutical, toxicological and medical disciplines

Evaluation of local tolerance of a plant extract by the slug mucosal irritation (SMI) assay

This article describes the performance of a laboratory exercise, the Slug Mucosal Irritation (SMI) assay, carried out by third year undergraduate students, to investigate the local tolerance of an ethanolic plant extract. The plant extract, Spilanthes acmella, contains various bio-active compounds, such as the N-alkylamide spilanthol. After administration of the plant extract to the slugs, they were observed for possible discomfort and tissue damage. When slugs are exposed to a substance with irritant properties, the mucus production of the slugs will increase. Furthermore, slugs will release proteins, including enzymes, when tissue damage occurs. This laboratory experiment is a practically feasible in vivo test using slugs which are invertebrates that are not protected by the legislation on animal testing. Students were supervised by lab instructors who encouraged students to actively contribute in their groups, to think about the experimental design of the laboratory test, and to facilitate scientific discussions, but the majority of the ideas had to come from the students themselves. Hence, this biomedical in vivo experiment offered a great opportunity for students to learn to work in group, to critically interpret and report their results, to gain knowledge about the subject, and to communicate and discuss with other students as well as with the lab instructors. Furthermore, this experiment teaches students current toxicological methodologies encompassing principles and their application of biochemistry, analytical chemistry, toxicology, animal experimentation and data handling. This way of interdisciplinary teaching is especially important for last year undergraduate students, as this is a good preparation for the Masters dissertation. At the end of the laboratory exercise, students received a questionnaire and most of the students indicated that they gained valuable knowledge and skills. This laboratory exercise can be incorporated into chemical, biological, pharmaceutical, toxicological and medical disciplines

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.

PURPOSE: 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 METHODS: 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 RESULTS: 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. CONCLUSION: 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.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

Development and optimization of a screening method for clinical discomfort using the Slug Mucosal Irritation test

When discomfort is associated with application of a certain product, patients and consumers may be less likely to adhere to the prescribed regimen or continue using a product. From a medical perspective this may affect the outcome of a certain treatment. For cosmetic companies adverse sensory sensations related to a certain product withholds consumers from buying these products in the future. Except for animal and clinical tests, to date no study is able to demonstrate the ability of a single, alternative method to predict human discomfort. Thus, academic, pharmaceutical and cosmetic research and development agencies would benefit from the development of a quick, relevant, reproducible test method to screen new and existing chemicals, active ingredients, pharmaceutical formulations and cosmetics for their discomfort potential. In the past, the Slug Mucosal Irritation (SMI) test was developed as an alternative mucosal irritation test using slugs as test organisms. The slug’s mucosal tissue histologically resembles human mucosa. When it comes into contact with an irritating substance, the slug will produce mucus. Mucus production was therefore selected as the endpoint for irritation. Previous research of our group demonstrated a relation between an increased mucus production in slugs and an elevated incidence of stinging, itching and burning sensations in humans. During this PhD research project, a new protocol was developed based on the principles of the SMI test, specifically focusing on the evaluation of clinical discomfort. Its applicability and clinical relevance to predict ocular and nasal discomfort was demonstrated by means of clinical trials. Indications for its usefulness for the prediction of dermal discomfort were also found, but more research is needed. Concluding, the new test is a promising screening method for clinical discomfort

Partial hydrolysis of poly(2-ethyl-2-oxazoline) and potential implications for biomedical applications?

The hydrolysis of PEtOx is studied to evaluate the potential toxicity of partially hydrolyzed polymers that might interfere with its increasing popularity for biomedical applications. The hydrolysis of PEtOx is studied in the presence of digestive enzymes (gastric and intestinal) and at 5.8?M hydrochloric acid as a function of temperature (57, 73, 90, and 100?degrees C). It is found that PEtOx undergoes negligible hydrolysis at 37?degrees C and that thermal and solution properties are not altered when up to 10% of the polymer backbone is hydrolyzed. Mucosal irritation and cytotoxicity is also absent up to 10% hydrolysis levels. In conclusion, PEtOx will not decompose at physiological conditions, and partial hydrolysis will not limit its biomedical applications