APR Nov/Dec 2022 - 60

»
DRUG DELIVERY
»
Stretching the Limits of
Dry Powder Pulmonary
Drug Delivery
Pauline van der Wijst - Janssen
Product Application Specialist in DFE Pharma's Inhalation division
Ross Blezard
Product Application Specialist in DFE Pharma's Biopharma division
The administration route of a drug is a critical decision during medicine
development: it can decide the success or failure of the drug product.
During the development process clinical factors (such as efficacy in
humans and patient compliance) as well as commercial factors (such
as development and manufacturing costs) have to be taken into
account. There are many defined routes of administration, which can
be loosely classified into three groups: Enteral, where a medicine is
delivered through the gastrointestinal tract, for example with tablets
and capsules. Parenteral, which in strict terms would indicate any
route other than the enteral route, however, is commonly associated
with injectable routes such as intravenous (IV), intramuscular (IM),
intradermal (ID) or subcutaneous (SC). Whilst parenteral administration
routes are effective from a clinical standpoint, they are not considered
patient-friendly administration routes (specifically IV). The final
administration route we can term as " other " ; this is where inhalation
and pulmonary delivery may offer a patient-friendly alternative to IV.
Pulmonary delivery of a water-soluble API has a multitude of benefits
over other established patient-friendly routes of administration, like
oral delivery. The large surface area available for absorption in the
lungs typically results in a rapid and predictable onset of action.
Pulmonary delivery largely avoids the first pass metabolism, meaning
that higher concentrations of the active drug are available at the site of
action. Additionally, drug delivery to the targeted tissue area can result
in fewer side effects.
Pulmonary administration is currently an essential
route in the
treatment of respiratory conditions. Dry powder inhalers (DPIs), are
non-invasive devices designed to deliver dry powder to the lungs
upon inhalation. DPIs have been used in the treatment of diseases,
such as asthma and chronic obstructive pulmonary disease (COPD), for
decades. Pulmonary drug delivery is a growing area with new products
designed to treat everything from diabetes to neurological conditions
currently making their way through the development pipeline and
into clinical practice.
DPIs have advantages over other forms of pulmonary administration
devices like nebulizers, metered dose inhalers and soft mist inhalers
(see Table 1). They are, for example, portable, easy to use, and contain
the formulation in a dry form. What's more, they have a relatively low
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APR Nov/Dec 2022

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