The University of California San Diego, Skaggs School of Pharmacy and Pharmaceutical Sciences Drug Discovery course brings you lectures from both faculty and industry experts. With this course, recorded on campus at UCSD, we seek to share our access to top people in the field who bring an unprecedented range of expertise on drug discovery. In this course you will learn the drug discovery process up to the filing of an Initial New Drug Application or IND. Each week you will learn the steps that a pharmaceutical or biotech company goes through to discover a new therapeutic drug. In this course you will be able to: * Understand the pharmaceutical and biotechnology market a changing landscape * Learn the major aspects of the drug discovery process, starting with target selection, to compound screening to designing lead candidates. * Recognize current modern drug discovery based on the lock-and-key theory, which attempts to use one single compound to hit one target to combat the related disease. * Increase understanding of the various drug discovery tools and methods that are used for finding, identifying and designing a new drug. * Define and understand the regulatory responsibilities for drug discovery to file an Investigational New Drug Application (IND). This course is intended as part 1 of a series: Drug Discovery, Drug Development (https://www.coursera.org/learn/drug-development) and Drug Commercialization (https://www.coursera.org/learn/drug-commercialization). We would highly recommend that you take the courses in order since it will give you a better understanding on how a drug is discovered in the lab before being tested in clinical trials and then launched in the market place.
Key Concepts in Drug Delivery V
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Del curso dictado por University of California San Diego
Drug Discovery
205 calificaciones
De la lección
Key Concepts in Drug Delivery
This module we hear from Professor of Clinical Pharmacy and Pediatrics, Brookie Best, Pharm. D., of UCSD's Skaggs School of Pharmacy and Pharmaceutical Sciences.
Conoce a los instructores
Williams S. Ettouati, Pharm.D.Director, Industrial Relations & Development; Health Sciences Associate Clinical Professor, N.S.
Skaggs School of Pharmacy and Pharmaceutical Sciences
Joseph D. MaAssociate Professor of Clinical Pharmacy
Skaggs School of Pharmacy and Pharmaceutical Sciences
I'm going to run through a few more of these.
Liposomes have been around a long time. What you start to see is combining some
of these interesting delivery systems with ways that you can formulate the drug
into something unique that will work well.
so liposomes help encapsulate something that would normally be broken down or
wouldn't be able to penetrate and get to the right area of the body.
So you might see and these liposomes, they're just lipid bilayers surrounding
your drug, and they just eventually melt away, degrade in the body and that
releases your drug. So, there's something called
biodegradable systems. You can infuse your drug into this
biodegradable, like kind of jelly or gel-like substance and you can inject it
into the body. And your normal water content in your
body just slowly breaks it down and breaks it apart, slowly releasing the
drug. And then the gel-like stuff that was
there just breaks apart into substances you already have in your body anyway.
So they kind, kind of take advantage of some unique substances.
>> I have a question. >> Yeah.
>> Does the size of the pill correlate at all with the duration of the
infection? >> a little bit, so not much.
The size of the pill might correlate a little bit with how quickly it can pass
through your stomach. So, the smaller the pill, the more
quickly it can dissolve or the more quickly it'll just pass through your
stomach even if it's still in part together.
the larger pills will sit in your stomach longer.
And your intestines are the major side of drug absorption.
You don't absorb much from your stomach because the intestines have a huge
surface area compared to your stomach, and they have a much more porous
permeable membrane. It's much easier for drugs to cross
through the membrane of the intestines than it is at the stomach.
The mucus lining is thinner. You know, there are lots of differences.
So if you have a very large pill, even if you haven't taken it with a meal, it
might sit in your stomach a while longer, and you'll only start to see the
absorption when it gets broken down enough to pass into your intestines.
So you'd see a delay, maybe in absorption.
But once it reaches your intestines, it's going to travel through those about, at
a, at the same pace that the smaller pill would.
So, it really only affects sort of that initial time frame of absorption.
Yeah? >> If you had a small pill and it just
went directly out of your stomach. Would it dissolve as it goes through the
rest of the small intestine or would it get out into the large intestine It could
be either? >> It could be either or depends on the
characteristics of that pill. So you can get undigested, you know,
material all the way through your intestines and excreted out in the feces.
Hopefully, you've designed your drug or your solid oral dosage form to break
apart well enough, that it will dissolve throughout your intestines.
It's fluid filled, it's moving an pulsing and mixing, and so, you do dissolve stuff
all the way if its not already dissolved. You can continue dissolve in the
intestines, so, but it really depends on that drug and that pill form.
Alright, another example that a lot of people are doing a lot of research in our
nanospheres. And again, trying to figure out a way to
protect the peptide or the protein or some drug that's not well-absorbed orally
through maybe something very small that you could trap it in, and if it's small
enough, maybe it could be absorbed orally, okay?
So, there's a lot of work being doing in nanospheres they're looking at this, not
just for drug delivery, but also for like, diagnostic testing and things like
that. So, and, for example, a rat study showed
an insulin nanosphere formulation was able to be absorbed orally.
You can have conjugated farms you might do something like, this is an example of
a drug called Neupogen, where the drug itself, Neupogen is very rapidly
eliminated by the body, so you have to dose it everyday.
But if you just conjugate it to this polyethylene glycol chain, it makes a
conjugated form of pegfilgrastim. Instead of dosing it once a day, you dose
it once a month or once every three weeks or something like that.
So it's the same drug conjugated to an inert substance that doesn't harm our
body, but makes the drug stick around a heck of a lot longer as it slowly gets
released from that conjugated form. So, you can get pretty fancy.
Slow-dissolving salt forms is another example of converting a substance into a
salt that maybe that breaks apart and dissolves very slowly.
You inject it into the [UNKNOWN] tissue and you don't have to dose it as often,
and insulin is one example that uses that form.
Okay, so that was a rapid fire [LAUGH] introduction at two, you know, know
trying to deliver drugs to the site of action in the body, okay?
But the take home message is, it's a lot more complex than it seems and whatever
the drug form is and whatever the disease state you're treating.
You've gotta figure out how to match the characteristics of the drug to a site in
the body where it will be able to be absorbed.
So that it gets to where it needs to be at the right time and in the right
amount, so that it'll have the action that you want and that it won't have any
toxicities that you don't want. So, it can get pretty complex.
And you start off from the most simple oral dosage forms and you hope that your
drug will work well in, maybe just a tablet or something like that.
As you need to get more complex and more elegant with your dosage forms,
typically, the cost rises tremendously. It's much harder to manufacture but you
can do some really unique things with you know, some compounds that you wouldn't
otherwise be able to administer orally. So, [NOISE] and you have to make sure
that it's in a method that the patient can actually use, which is harder than it
sounds. Especially, if you start to get into
these more complex injections or complex oral inhalation forms or even complex
patches like those microneedles. Have, devices that you have to use to
punch them into the skin, and then, fold over the patch with the drug attached to
it. And so, you, you do start to run into
issues of, are the patients ever going to be able to use this correctly?
and you have to think about that when you're formulating your delivery system
or your dosage form. So, I think that's all I have for you
today.
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