The Science of Drug Delivery within the Skin

What is skin?
Anatomically, the skin is made up of two primary tissue layers, an outer epidermis, and an underlying dermis, which together constitute the skin. The dermis itself contains two layers: the outermost layer is referred to as the papillary dermis while the deeper layer is known as the reticular dermis. The papillary dermis contains vast microcirculatory blood and lymphatic plexuses. Beneath the dermis is the subcutaneous tissue, which is composed of fatty and muscular tissue and an abundance of nerves.

There are three primary methods by which drugs may be injected: intramuscularly, subcutaneously and intradermally.

The intradermal injection method typically requires a standard needle to be carefully inserted into the dermis at an angle of 15 degrees, making it a precise and awkward procedure for the user. It has been the major challenge for patients or care-providers administering an intradermal injection and is why a syringe is best used to administer into the subcutaneous or intramuscular tissue.

By targeting the skin (intradermal), the drug delivery can take place anywhere on the body rather than in the usual five, often overused, sites of subcutaneous injection. This has proven to enhance the uptake, bio-availability and efficacy of drugs.

Syringe needles inject deep into muscular tissues

Needles on outdated syringes go over 8 millimetres deep into the fatty and muscular subcutaneous tissues and we feel pain because that’s where our nerve endings are. Conventional methods of injecting drugs provide a less direct dispersal of the drug.

Our Micro-Needle is a pain-free shallow injector

The PKA SoftTouch Micro-Needle is the ONLY patented device that injects the drug directly beneath the skin layer. The tiny needle enters the skin only by 1.5 millimetres, not deep enough to hit the nerve junctions and cause pain.

Shallow drug delivery improves medication uptake

The shallow injection into the skin allows the drug to enter the bloodstream through interstitial fluid. This fluid circulates through the body and disperses the medication faster than any traditional needle injection. By targeting the epidermal layer of the skin, we have proven that a shallow delivery process enhances the uptake, bio-availability and efficacy of drugs.

The pressure required to administer the drug is minimal. Since the drug doses are premeasured in the PKA Micro-Needle and ready for use, there is no mess, no over or underdosing, and best of all, no pain. The needle is retracted into the housing and is locked inside; therefore, no sharps disposal is required.

The needle is fabricated and mounted in the centre to prevent the obstruction of the injection channel while penetrating the skin.

What is the Dermis layer?
The skin is made of two major tissue layers (epidermis and dermis). The dermis contains two layers (papillary, and the deeper layer, the reticular dermis). Beneath the dermis is the subcutaneous tissue (s.c.), composed of fatty tissue and nerves. The subcutaneous tissue is the threshold in which traditional needles pass through therefore creating pain. The Micro-Needle delivers the drug above the subcutaneous tissue and is therefore pain free.

The injected drug is then carried to the bloodstream by the interstitial fluid that lies between the skin layers. As the skin is the largest organ in the body, it rapidly disperses the drug into the bloodstream, twice as fast as a subcutaneous injection. Drug doses are pre-measured in the device and ready for use. Different dosages will be indicated by coloured caps, providing drug dosage accuracy and a level of safety currently unavailable. NO MESS – NO OVER OR UNDER DOSING – NO PAIN