Reliability and accuracy of intradermal injection by Mantoux technique, hypodermic needle adapter, and hollow microneedle in pigs

We compared the ability of three intradermal delivery devices to administer an intended dose to pig skin in vivo and target that dose to the dermal rather than subcutaneous layers. The three devices were a standard hypodermic needle and syringe for the Mantoux technique, an adapter designed to facilitate proper hypodermic needle and syringe use, and a hollow microneedle. Reliability was determined as the percentage of the administered dose that entered the skin, as opposed to remaining in the device or on the skin surface. The intradermal adapter (97.6 +/- 1.5 % delivered, mean +/- standard deviation), Mantoux technique (95.4 +/- 4.9 %), and hollow microneedle (94.9 +/- 0.3 %) exhibited similar reliability. Accuracy was determined as the percentage of the dose that entered the skin that localized in the dermis. All three devices achieved similar accuracy: hollow microneedle (99 +/- 12 % delivered to the dermis, median +/- standard deviation), Mantoux technique (97 +/- 16 %), and intradermal adapter (92 +/- 21 %). We conclude that intradermal injection by all three methods studied provided reliable delivery to the skin and provided accurate localization of delivery within the dermis. Next-generation designs of these devices have now received clearance from the FDA and are used as medical products and/or in clinical trials.