Unlocking the intradermal route

The Mantoux technique, the traditional method of delivering therapies by injection through the skin, is difficult to use and prone to mis-injection. BD Soluvia™ is an innovative microinjection system that allows simple and reliable intradermal injection.

	BD Soluvia: an easy-to-use and reliable means of delivering therapeutics to the intradermal space.

The skin, as the largest interface between the body and the outside world, has unique properties that make it advantageous for the delivery of therapeutic agents. The dermal layer contains a network of lymphatic vessels that feed local lymph nodes, resulting in rapid and efficient access of antigens to the immune system. It also contains a high concentration of potent immune cells that play a key role in initiating the immune response following vaccination.

The measurement of skin thickness in 342 subjects showed no significant differences according to age, race, gender or BMI. For intradermal injection using a 1.5mm microneedle inserted perpendicular to the skin surface, the thickness of deltoid, suprascapular and waist regions would ensure administration into the dermal layer.

New approach
The intradermal space also contains an extremely dense network of terminal capillary loops that are connected to the peripheral vascular system. In fact, each square millimetre of human skin contains an estimated 60 to 75 capillary loops and this vascular density is ten times higher in the upper intradermal space. In some respect, this is similar to the dense microcapillaries found in the lung alveoli. Thus, rapid drug uptake in the bloodstream from the skin dermis occurs mostly through this extremely rich intradermal vascular network.

BD Soluvia™ is an innovative microinjection system developed by Becton, Dickinson and Company (BD) that allows intuitive, simple and reliable intradermal injection. BD Soluvia has a 30 gauge, 1.5mm-long needle with a short bevel; it is inserted perpendicularly to the skin surface. It corresponds to the skin anatomical requirement for fluid delivery in the dermis.

Intuitive and reliable
Studies have documented that BD Soluvia consistently and reliably delivers the right dose exactly in the dermis. In a swine model, the use of 3D ultrasound echography and histological examination of injection sites demonstrated that the injected fluid was delivered precisely into the intradermal space. Scoring of injection success with X-ray imaging showed that injections were generally more satisfactory with BD Soluvia than with the conventional Mantoux technique.

The amount of fluid effectively delivered was also extremely consistent, regardless of the operator. A trial involving over 3,000 injections and 168 practitioners divided into groups with various levels of training (intensive, medium, none and intentionally misleading) demonstrated that no training was needed before successfully using BD Soluvia. Thus the BD Soluvia microinjection system is very intuitive and easy to use.

Simply innovative
BD Soluvia is pre-filled and ready to use, eliminating the preparation time required with the conventional vials and tuberculin syringe. Also, since the needle is already affixed to the syringe, there is no need to use luer transfer needles. After use, no purging of the syringe is required and the needle protection shield that is activated by the user provides for built-in needlestick prevention.

Another advantage is its short, thin and minimally invasive microneedle. A 30 gauge is significantly smaller (around 50% less in diameter) than the 26 gauge used for Mantoux injections. Moreover, the shallow depth of the injection (1.5mm) and the small injected volume (typically 100uL) make the BD Soluvia microinjection system minimally invasive. All these factors may contribute to the near imperceptible perception of the microneedle by patients.

By providing an innovative, easy-to-use, intuitive and reliable means of delivering therapeutics to the intradermal space, BD Soluvia is expected to revive the use of this route of administration and possibly expand the use of some drugs.