Assessment of Forces in Intradermal Injection Devices: Hydrodynamic Versus Human Factors

Abstract

The force assessment method and the model can be used to pinpoint needle geometry for intradermal injection devices, tuning comfort for subjects and usability for operators.

Dissolving Candlelit Microneedle for Chronic Inflammatory Skin Diseases

“…Besides the needle insertion direction, the volume or insertion rate of structures inserted into the skin tissue are significant factors in evoking pain. [ 10 , 30 ] In the current TAILI procedure, a 0.1–0.2 mL TA suspension is injected at each point (1 cm 2 ). [ 6c ] In contrast, the total volume of our Candlelit‐DMN inserted per 1 cm 2 was only 1.93×10 −3 mL (out of 61 needles, 55 were located within 1 cm 2 with each needle volume being 0.035 ± 0.001 mm 3 ; Figure 2 and Figure S2 , Supporting Information), which is much smaller than the volume used in the TAILI procedure.…”

“…[ 6c ] In contrast, the total volume of our Candlelit‐DMN inserted per 1 cm 2 was only 1.93×10 −3 mL (out of 61 needles, 55 were located within 1 cm 2 with each needle volume being 0.035 ± 0.001 mm 3 ; Figure 2 and Figure S2 , Supporting Information), which is much smaller than the volume used in the TAILI procedure. Considering that minute volume insertion is crucial in reducing pain, [ 10 , 30 ] our Candlelit‐DMN could induce less pain than the TAILI procedure. Indeed, DMN application proved to be not painful and was well tolerated and accepted in humans.…”

“…[ 8 ] Despite its efficacy, the severe pain caused by TAILI causes patients to be stressed and reluctant to undergo treatment, especially children and elderly individuals. [ 6 , 9 ] Furthermore, due to the technical attributes of TAILI itself, the physician‐dependent amount and depth of the TA injection [ 10 ] and uneven distribution of TA in the skin make it difficult to predict the outcome from lesion to lesion. Additionally, several side effects can occur, such as persistent scarring secondary to ulceration, [ 11 ] linear atrophic streaks, [ 12 ] or dyspigmentation in perilesional skin.…”

In-vitro assessment of release of silicone oil droplets with the use of variety of syringes and needles used in intravitreal injections

“…Also, it is known that higher gauge needles result in higher injection force, according to the Hagen-Poiseuille equation, which might cause the needle to pop off. 18 The equation states that the pressure to inject is inversely proportional to the radius to the fourth power, meaning that a small decrease in the internal diameter of the needle results in a significant increase in the pressure required to expel fluid.…”

Awareness on Intradermal Injection among Dentists

“…Nonhuman primates are screened for tuberculosis using an intradermal injection. Intradermal injection avoids the barrier presented by the stratum corneum and injection site entry into the general circulation is mainly limited by the rate of blood flow [5]. Nonetheless, these sites usually only permit the administration of small amounts of drugs and tend to be primarily used for local effects, such as local anesthesia [6].…”