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Smart drug devices
These are the times where devices rule every aspect of the
human life. Slowly but steadily technology is trickling into drug delivery making
them smarter, more functional and practical. Katya Naidu discusses the
working of some of next generation medicines.
 The
system of medicine since times immemo-rial has concentrated on curing and eradicating
diseases. However, ever since the average life span increased the pressure is
built up on the healthcare systems to make people sustain medication for long
periods of time with least changes in lifestyle. This has necessitated the need
for the so-called smart drugs with technology powered delivery systems that
require fewer efforts from the patient and the doctor.
Doctor machine
It is universally accepted that an insulin pump is a better
method of insulin delivery. But the new age pumps have gone a step ahead to
indicate the glucose levels of the patient. Medtronic's MiniMed Paradigm Real-Time
Insulin Pump and Continuous Glucose Monitoring (CGM) system comes in with a
glucose sensor that gives continuous glucose readings and trend graphs. This
information can mean a lot to diabetics since patients on insulin therapy are
prone to hypoglycaemia wherein the glucose level suddenly drops. By indicating
the condition of the body way before it affects the person, the perils can be
controlled and can revolutionaries diabetes treatment in the future. "In
order to manage diabetes properly, patients must continually understand what
affects their glucose patterns and take action to regain control as quickly
as possible. By viewing trends and real-time glucose information, patients can
program their pump to start or stop insulin delivery upon demand, or they can
eat carbohydrates to counteract for low blood sugar," states Dr V Mohan,
Chairman of Dr Mohan's Diabetes Specialties Centre in Chennai, India.
The glucose sensor is a tiny electrode that is inserted under the skin using
the Sen-Serter, a small device that makes sensor insertion easy for patients
or their caregivers. The sensor measures glucose in the interstitial fluid found
between the body's cells, and is typically discarded and replaced after three
days of use. Glucose measurements obtained by the sensor are relayed every five
minutes from a transmitter to the external insulin pump, which displays three-hour
and 24-hour trend graphs. It also has arrows which indicate how quickly glucose
is moving up or down. In addition, an alarm alerts patients when glucose levels
become too high or too low. "The MiniMed Paradigm REAL-Time System marks
a major step toward the development of a closed-loop insulin delivery system
that mimics some of the functions of natural pancreas," says Milind Shah,
Managing Director - India Medtronic.
The system incorporates "smart" MiniMed Paradigm 522 or 722 insulin
pumps, which have powerful built-in Bolus Wizard calculators to manage the complex
diabetes math for patients. These pumps recommend insulin dosages after considering
the amount of insulin still "active" in the body, helping patients
avoid dangerous hypoglycemic episodes. The system is calibrated twice a day
(every 12 hours) by entering a blood glucose measurement from a standard meter
into the insulin pump. "We are seeing encouraging results in clinical trials,
and believe a fully-external system is the most viable option for diabetes patients
in the future," Shah asserts.
The system also overcomes the limitations of the current standards for assessing
glucose control like A1C tests and fingerstick measurements. An A1C test, which
measures glucose control over a three-month period, is important for long-term
management. But it is only an average and does not reveal day-to-day glucose
fluctuations that can damage the body. Fingerstick measurements reveal a glucose
value at a single moment in time. As a result, patients cannot detect approximately
60 percent of low glucose (hypoglycemia) events and have difficulty assessing
glucose fluctua-tions while they sleep. In contrast, CGM allows patients to
view glucose trends throughout the day and night, and understand how fast, and
in what direction, their glucose levels are heading. "Not only do patients
get their insulin delivered in a more physiologic way but also they get real
time glucose trends on the screen of the pump which empowers them to take decisions
for optimal treatment of their glucose levels," observes Shah. The system's
glucose sensor takes as many as 288 daily glucose readings per day - providing
nearly 100 times more information than three daily fingerstick readings provide.
| Novel drug delivery systems have started off with
fast acting medicines, flash tabs and once-a-day regimens. From painful
injections to easy-to-pop tablets, the new age smart medications are looking
at eliminating the pill popping dilemma as well with inhalable medicines.
First in the list to go in for the inhalable version is the fast acting
insulin.
Developed in a joint effort by Aventis and Pfizer, Exubera
is an insulin rDNA origin powder for oral inhalation. Indicated for the
treatment of adults with Type 1 and Type 2 diabetes, Exuberal is rapid-acting,
dry powder insulin which is inhaled through the mouth into the lungs prior
to eating, via a proprietary inhalation device. The powder form of insulin
is pumped into a closed chamber from where it can be inhaled. The insulin
particles, stabilised with sugar travel to the alveoli where they dissolve
and transverse the tissue to enter the bloodstream. This new version,
in addition to being a boon for needle phobiacs, is also highly bio-available
and effective, according to some studies.
However, there are also certain drawbacks as about 90
percent of the insulin is lost in the air and nasal passage. It is also
to be noted that inhaled insulin alters the function of the lung by one
percent and the capacity to blow out a certain volume of air in a second
is slightly reduced for a person using this insulin. Moreover, people
suffering from asthma cannot use this form of insulin since the air passage
is blocked and the amount of insulin that reaches alveoli is insignificant.
Another inhaled form of a drug that was introduced in
India by Baxter last year. Suprane (desflurane) is one of the latest advancements
in the field of inhalation anaesthesia. Suprane is associated with the
fastest recovery from effects of anesthesia and least post-anaesthesia
complications, the company claims.
Particularly useful for long duration surgeries and obese
surgical patients, Suprane also boasts of a good safety profile with minimal
potential to react with other chemicals in anaesthesia machine (Suprane
is administered through vaporizer machines). It also has minimal adverse
impact on organs like liver and kidneys. "Suprane is ideally suited
for practice of low-flow anaesthesia, a globally accepted technique that
reduces cost and environmental pollution", says Dr Maddirala Subrahmanyam,
Consultant Axon Anaesthesia Associates, Hyderabad.
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Painless devices
 Moving
ahead from external devices which give information of the body,
certain not-so-very futuristic devices plan to settle inside the
body and deliver drugs. One such pain management device is under
development by HCL Technologies for an unnamed MNC company.
The device comprises of a battery-operated, ultra-low power unit controlled
via wireless medium. One part of the device is implanted inside the sub-cutaneous
layer of the body via surgery. It contains the drug and has an extension, which
is close to the pain area and enhances site specificity of the drug delivery.
Since there is a limit of drug, which the device can take with it at once and
surgery is not possible every time it runs out of the drug, there is an option
wherein the drug can be replenished through an injection.
The other part of the device which is connected wirelessly to the first device
is with the doctor which can be used to regulate drug flow. The doctor can use
his computer to alter the dosage regimens. Variable drug delivery ensures that
the same amount of drug need not flow into the body all the time. "If the
pain is not that high in the morning, you can programme the device in such a
manner that less amount of drug goes in the morning," says Apurva Chamaria,
Category Marketing Manager of Life Sciences Division, HCL Technologies. In addition,
the device requires minimal drug as compared to normal delivery system.
The implant is indicated for classic cases of recurrent chronic pain like arthritis,
back pain and spasticity where behavioural angle affects the dosage and makes
therapy difficult. Doctors face the problem of self-medication where patients
determine the dosage amount depending on the intensity of the pain and overdose
themselves. This device completely eliminates the intervention of the patient
and makes the doctor the final authority of the dose that enters the system.
A cardio dilemma
Yet another smart device launched recently is the Opto Circuits is Dior, a paclitaxel-eluting
balloon dilation catheter used in PTCA (percutaneous transluminal coronary angioplasty)
procedures. The one-of-its-kind life saving catheter can be effectively used
in treating a condition where a person who has a stent inside gets blocked again
a process called in-stent restenosis. "One way to treat this is you can
go into a stent and put another stent inside the stent to open the blockage
or you can take one of these Dior balloons, go in and elute the drug into the
blockage and it clears the vessel out," says Jayesh Patel, the Director
of Opto Circuits.
There are also cases where there is not enough room to put another stent in
thereby mandating a bypass surgery. Dior can also be used in such cases. "There
are a lot of cardiologists who would never go near a bifurcation just stay away
from it. With Dior one can go to the bifurcation, open the occlusion and implant
the drug at the occluded spot where the retenosis has occurred," says Patel.
In the conventional method, one can only go in with a balloon, expand it to
open the artery for sure but the artery would get occluded (artery blockage)
again because there is no drug there to stop the growth. Though invasive devices
could get risky, this stent has no major side-effects. "It works or it
does not work and when it does not work it does does no harm either and you
would require a bypass surgery," confirms Patel.
Though these innovative hi-tech devices have an answer to most of the problems,
there is no dearth of new methods which are being ideated. And one such idea
in progress is a bio-absorbable stent which would dissolve into the body in
four to five months!
katya.naidu@expressindia.com
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