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Harnessing the Power of Desiccant Technology for Inhalation Therapies
Active packaging components such as sorbents regulate
moisture levels in dry powder inhaler (DPI) systems. |
Exubera - the first inhaled form of insulin for treatment of diabetes - made headlines
when it received FDA approval earlier this year because it promises to free diabetics
from the discomfort and intrusiveness of mealtime injections. This new drug joins
a growing suite of pharmaceuticals that are being packaged in fine powder form
for use in inhalation devices. For clinicians and patients, respiratory drug delivery
offers several advantages over conventional delivery methods, including precise
dosing, speed of action, and convenience. To succeed in the emerging market for
inhalation therapies, pharmaceutical manufacturers need to understand the design
and production challenges unique to this form of drug delivery.
Active packaging components are a critical consideration for creating a successful
dry powder inhaler (DPI) system, especially the role of sorbents for regulating
moisture levels inside a DPI . Sorbents facilitate the smooth flow of drug particles
and ensure that the device works, accurately, throughout its life cycle. The choice
of sorbents, however, and their incorporation into a package or delivery device
requires careful consideration to ensure effectiveness.
Understanding the Market
The demand for inhalation therapies is fuelled by several factors, including new
clinical applications and the growth of chronic conditions. Delivering drugs through
the lungs is faster than oral delivery and can offer more controlled dosing, thus
avoiding or minimizing most systemic side effects. Inhalation therapies are commonly
used for treatment of asthma or chronic obstructive pulmonary disease - the world’s
fourth-greatest cause of death. However inhalation therapies have begun to be
used with biologics, which have typically been administered intravenously or through
injection. Inhalation therapies are also being deployed for pain management, in
which speed and ease of delivery are paramount.
Because inhalation therapies offer a relatively painless, convenient mode of drug
delivery, industry experts note that they could increase patient compliance with
recommended treatment - a particularly important consideration for management
of chronic conditions. By improving compliance and providing more accurate dosing,
DPIs have the potential to increase the efficacy and cost-effectiveness of drug
treatments.
Going with the Flow
Coated solid format (CSF) sorbents significantly
increase the level of functional desiccation per unit volume
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New inhalation therapies are made possible through the creation of novel delivery
systems. There are a variety of DPI models, which manufacturers often customize
to meet the needs of a particular product or patient population. Some DPIs include
pre-measured doses of medicine in blisters, capsules, or other cavities that are
inserted into the device before use. Once a patient uses all the doses, they discard
the device. By contrast, “reservoir” devices offer continued use from a drug reservoir
until the reservoir is depleted. They include an internal supply of a drug, which
is measured and dispensed in the device itself.
Sorbent technologies are an important component of any DPI system. Not only do
sorbents preserve the potency and stability of drug formulations, but they also
maintain air flow dispersion, ensuring accurate dosing. Like other pharmaceuticals,
powdered drugs are subject to physical and chemical degradation. If moisture builds
up inside a device, drug particles tend to agglomerate - making them too large
to be inhaled or leaving some amount stuck to the device walls. Drug particle
agglomeration can reduce the ability of the dry powder to flow through the system
and affect the accuracy of dosage. In addition, excess moisture can cause changes
in the potency or stability of powdered drugs by increasing their molecular mobility
and fostering chemical degradation.
Taking Advantage of New Desiccant Technology
Because proper desiccation is an integral part of DPI device functioning, the
choice of sorbent is crucial. Today’s sorbents are often described as “active
packaging components” because they respond to changes in the headspace of packaging
relative to outside conditions. In this way, they regulate humidity levels within
a DPI device without making contact with the dry powder and optimize conditions
for drug delivery.
A new generation of desiccants - coated solid format (CSF) sorbents - is particularly
well suited for DPI applications because they significantly increase the level
of functional desiccation per unit volume. Through condensed density technology,
CSF sorbents are able to deliver twice the moisture protection in the same dimensional
space as a typical loose-fill desiccant. CSF sorbents can be made from silica
gel, activated carbon, or a combination of both.
To facilitate ease of use, manufacturers are designing inhaler devices in discreet
forms, along the lines of lipstick cases or eyeglass holders. CSF sorbents can
easily integrate into DPI designs because they can be manufactured into a variety
of shapes and sizes. If there is an available cavity inside a particular DPI device,
a CSF sorbent can be customized to fit inside of it, creating an “onboard” solution
for pharmaceutical preservation. If there is no available space within the inhalation
device itself, CSF sorbents can be produced in strip format and packaged alongside
a DPI.
Fine-Tuning the Desiccation Process
Adrian Possumato is Global Manager-Pharmaceutical Market
with Multisorb Technologies, Inc. (Buffalo, NY) |
Finding the right level of desiccation for powdered drugs, however, can be tricky.
While excess moisture can degrade drugs, over-desiccating can change electrical
charges, generating static electricity that interferes with the dispersion of
drug particles or denaturing biologically active molecules. Determining the correct
desiccation formula should be part of an overall DPI design in which user control,
air flow, static electricity, and moisture play interdependent roles.
When evaluating the desiccation requirements for inhalation devices, pharmaceutical
manufacturers should consider the interactions between drug formulation, device,
and packaging. They must also consider all of the sources of moisture, including
the plastic from which a device is manufactured and any inserts or other components
of the package. Sorbent producers should be able to provide expert advice to manufacturers
during the design, production, and approval processes.
Finding the Right Solution
Respiratory drug delivery is a significant new trend, offering clinical benefits,
dosage control, and patient convenience. Integrating sorbent technologies into
dry powder inhalation devices will preserve the quality and safety of pharmaceutical
formulations and ensure that the device functions accurately and effectively each
time it is used.
About the author: Adrian Possumato is Global Manager-Pharmaceutical Market with
Multisorb Technologies, Inc., Buffalo, NY. He can be reached at apossumato@multisorb.com.
908-849-3005.
Pharmaceutical Processing
Advantage Business Media
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