Sr. No. | Study | Observation | Toxicity effect | Result/inference | Ref. |
---|---|---|---|---|---|
MNs free from in vivo and in vitro toxicity | |||||
1. | The standard Draize skin irritation method was used to measure erythema and edema of the thiolated CS-MNs patch of tacrolimus. | After 1 h, the removal of thiolated CS-MNs loaded tacrolimus has increased erythema score. | No edema was exhibited | An elevated quantity of needles might cause these symptoms, which could be parallel to the increases in the number of pores per unit area of skin. | [140] |
2. | A piece of rat dorsal skin was defrosted naturally, and then the curcumin micelle-loaded dissolvable composite MNs were inserted with the thumb using a force (5 N). Then MNs were removed after the insertion and the skin was exposed to trypan blue solution for 5 min. | The blue dot matrix was found on the surface of rat skin after being washed with a saline solution. | No any inflammation and irritation occurs | The dye could not penetrate the SC, but it can stain the inner tissue through the microholes generated in the skin layer. | [141] |
3. | The hair on the back of each rat was shaved, and the aconitine loaded diethylene glycol monoethyl ether-mediated microemulsion assisted MNs was applied once daily for 7 consecutive days. | The cell morphology of each layer was found to be normal after the exhibition of the test. | No obvious irritant reaction and no inflammatory reaction were found. | Because of the microemulsion, the aconitine constant subcutaneous distribution obtained, which resulted in the diminishing the toxicity | [142] |
4. | 5-Fu loaded monomethoxy-poly(ethylene glycol)-polycaprolactone NPs integrated HA dissolvable MNs was evaluated for in vitro cytotoxicity by human epidermoid cancer cell line-A431 and the human melanoma cell line-A375 through MTT assay. | It was demonstrated the cell inhibition ability almost similar to 5-Fu and showed a better inhibition at 48 h. | MNs have exhibited no obvious cytotoxicity without NIR laser. | The monomethoxy-poly(ethylene glycol)-polycaprolactone can a good carrier for 5-Fu delivery. | [103] |
5. | The gelatin methacryloyl and β-cyclodextrin (Gel-MA-β-CD) based MNs have penetrated the epidermal layer after 1 h of topical implantation. | No MN array-related damage or inflammation was found for up to 3 days. | No irritation and inflammation occur. | It showed biosynthetic Gel-MA-β-CD MN arrays were biocompatible with the skin and were potentially competent in sustained release of the drug. | [143] |
6. | In this study, two amifostine-armored MNs patches have been topically administered on the shaved dorsal skin (12 h). | No noticeable weight loss | No toxicity and inflammation in the major organs were exhibited | It showed that amifostine-armored-MNs were a harmless technique used for active delivery. | [139] |
7. | Acute skin irritation of 3 min treatment by the MTX-HA-dissolvable (MTX-HA) MNs was performed by using the dorsal skin of mice. | No erythema and swelling | No obvious irritative reaction | It increased the convenience and acceptability for frequent administration of drugs or active agent using the MNs technique. | [144] |
8. | The cytotoxicity study of drug-free PEGDA/sucrose MNs was performed by human umbilical vein endothelial cells (HUEVCs) by MTT cell viability assay. | The cell viabilities were all above 90% at the 1:20, 2:20, and 3:20 mass ratio of (sucrose/PEGDA), which is significantly higher than the viability of those incubated with MNs made of pristine PEGDA or PEGDA plus fibrin scaffold. | No cytotoxic reaction occurs | It confirmed that PEGDA/ sucrose MNs exhibited good biocompatibility, particularly after the incorporation of sucrose in the needle matrix. | [98] |
9. | The study was carried out by applying MNs (without drug) followed by NIR light irradiation. | No noticeable tissue lesion took place in this study. | No cytotoxic reaction and irritation occur. | It confirmed the hypo-toxicity and safety of as-fabricated MNs for potential clinical applications. | [72] |
10. | The Ex4 tip-loaded MN arrays and subcutaneous injections were compared for their acute efficacy in type 2 diabetic GK/Slc rats. | The pores created by MNs were much greater (disappeared at 24 h after application) than the one pore created by subcutaneous injection (remained visible even at 72 h after). | No inflammation | It confirmed that MNs’ arrays did not cause serious skin damage or irritation, and they can be safe after application. | [145] |
11. | The in vitro EpiDermâ„¢ skin irritation experiment on the EPI-200-SIT (reconstructed human epidermal model EpiDerm) has been conducted to examine the irritancy level of vismodegib solution. | The skin irritation test showed that the vismodegib solution was non-irritant to the reconstructed human epidermal model EpiDerm. | No irritation occurs | It proved that vismodegib formulation could be used safely on animal skin with no irritation to the application side. | [18] |
12. | The cytotoxicity of rapamycin- dissolving MNs were carried out on HUVECs, Cell counting Kit-8 assay. | The viability of HUVECs incubated vehicle dissolving MNs was higher than 80%. | No cytotoxicity | It showed the better biocompatibility of the dissolving MNs. | [19] |
13. | The lipid bilayer-coated with antigen-loaded mSiO2-NPs (LB-MSNOVA) for intradermal antigen delivery via coating MN arrays had tested for toxicity study. | The MNs can undergo hydrolysis to form a nontoxic by-product. The intravenously injected MNs were mainly excreted out of mice through urine and faces. | No cytotoxic reaction. | It shows that the developed MNs are biodegradable and safe for use. | [20] |
MNs showed in vivo and in vitro toxicity | |||||
14. | The dissolving MNs patch was successively applied on depilated mice’s back skin and physiological saline the negative control | It was observed that the dissolving MNs containing β–sodium Glycerol-phosphate and hydroxypropyl β-cyclodextrin induced slight mechanical damage. | The histopathological tissue section was exhibited. The mild inflammation in the cell infiltration is seen in the dermis. | The skin irritation caused because of dissolving MNs has mild and transient. | [136] |
15. | The mice group was transcutaneously treated with Ex4-loaded MN patch. | In this study, they induced the MNs patch administration and observed inflammatory reaction in comparison with intradermal injection of dual mineralized particles. | A slight inflammation reaction occurs | The less invasiveness of the MNs patch to the skin suggested that the Ex4-MNs patch is a highly biocompatible treatment. | [84] |
16. | The skin irritation after the successful application of alendronate-loaded MN array was calculated using the Draize method. | At 24, the irritation score after the application of a blank MN array was not changed. Besides, the light erythema of the skin was observed 4 and 8 days after a 24 h application of a microneedle array. | Slight erythema and edema and irritation occurs | Further, studies are needed to improve the safety of alendronate-loaded MN array. In this study, alendronate-induced skin irritation can avoid by incorporating antioxidants in the alendronate MNs. | [21] |