Usability evaluation of intradermal adapters (IDA).

Intradermal adapter device technology minimizes the complexity of the Mantoux technique, thereby providing predictable, reproducible intradermal (ID) injections and removing the concerns regarding the ease and reliability of Mantoux technique when using conventional needle and syringe. The technology employs a simple device with geometry designed to gently deform the skin surface and the subcutaneous tissue, providing the ideal angle and depth of needle insertion for consistently successful intradermal injections. The results of this development were presented at the First, Second and Third Skin Vaccination Summits in 2011, 2013 and 2015 respectively [1,2,3]. The current publication addresses the performance of intradermal adapters (IDA) evaluated in three preclinical studies. The evaluations were based on the assessment of bleb formation in a skin model, an accepted indicator of ID injection success. All evaluated devices share the same proprietary dermal interface technology. Devices instituting this design are easy to use, require minimal training, and employ conventionally molded parts and cannula. These studies evaluated IDAs of initial design integral with luer lock needles, IDAs for use with conventional syringes, and intradermal adapters for use with auto disable syringes (ADID adapters). The evaluated ID adapters were intended to consistently place the lancet of the needle at a depth of 0.75mm from the skin's surface. This placement depth addresses the variation in the skin thickness at immunization sites for the majority of patients independent of many other variables. Most participants preferred the intradermal adapter method over the traditional Mantoux and identified a need for the adapter at their workplace. Evaluation of IDAs by registered nurses indicated these devices increase success of bleb formation. The use of IDA increased the success of forming blebs by about 30%. Nurses felt the injections were much easier to perform, in particular by novices.

Clinical performance and safety of adapters for intradermal delivery with conventional and autodisable syringes.

Although the number of vaccines and diagnostic tests currently delivered intradermally is limited, this route of administration offers potential advantages due to the high concentration of antigen-presenting cells in the skin. One factor which may in part be limiting development and use of intradermal (ID) administration is concern about the ease and reliability of the needle and syringe-based Mantoux technique. A phase I clinical study was conducted to evaluate two ID adapters that have been developed as injection-delivery aids to increase the safety, simplicity, and reliability of ID injection: a prototype autodisable, intradermal (ADID) adapter for autodisable (AD) syringes, and a marketed side-merge adapter (SMA). Thirty healthy adult volunteers each received six injections of 0.1 mL of sterile saline solution. Each adapter was used to give injections into the upper deltoid, forearm, and suprascapular regions of each volunteer. The needle-bevel orientation during injection was random. Injection performance was determined by measuring wheal size and fluid leakage. Wheals were similar in size for the ADID adapter (mean 9.9 ± 0.17 mm) and SMA (mean 9.8 ± 0.15 mm). In all of the injections completed with the SMA, and 98% of those completed with the ADID, fluid leakage was less than 10% of the intended injection volume. Minor skin abrasions were the only adverse events. Based on self-reporting of pain, injections were well tolerated (mean pain score of 2 on a 0-10 scale). ID delivery using the SMA and ADID adapters appears safe and effective.