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dimethyl-,3-cyclodextrin role in intranasal bioavailability

hydroazuanacaine

hydroazuanacaine

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May 17, 2007
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alright, so in a study about the effectiveness of the intranasal ROA for clonazepam, it says they mixed the kpin with this dimethyl-,3-cyclodextrin before dissolving it in ethanol and the the water/saline solution. i tried to find info about dimethyl-,3-cyclodextrin, but everything is written in terms that go way over my head. could anyone explain to me what role dimethyl-,3-cyclodextrin has in affecting the ability of benzodiazepines to penetrate the nasal membrane? or less specifically, what role it has in affecting the ability of drugs (in general) to pass through different membranes in the human body?
 
Clonazepam is hardly water-soluble, but the base of almost all nasal sprays is water. Therefore, to enhance the solubility, a compound is added that can host clonazepam. This is the cyclodextrine. By this, one can achieve a higher concentration of the compound in your spray.

Don't forget that this complexation is an equilibrium. In the aqueous solution, the clonazepam will stay bound predominantly to the cyclodextrine, due to its polarity (as said before). Next to a membrane (i.e. your nasal mucosa), which is a hydrophobic environment, it can get released and cross the membrane.

Clear now? :)

PEACE! Murphy
 
so bonding the clonzepam to the cyclodextrine is only to make it water soluable (for the sake of dissolving it in the spray solution)? it does not increase the clonzepam's ability to cross the nasal membrane?
 
It's not a bond in the sense that Na and Cl bond to form salt or carbons bond to form a chain. It's an intermolecular attraction. X doesn't dissolve in Z. X dissolves in a solution of Y. Solutions of Y are soluble in Z. Thus, create a solution of X and Y and add it to Z.
 
flacky said:
It's not a bond in the sense that Na and Cl bond to form salt or carbons bond to form a chain.
Click to expand...

Na-cation + Cl-anion = ionic bond
C-C-chain = covalent bonds
...those are both "intermolecular attractions", so to say. Your examples don't make much sense.
Clonazepam is most probably hold inside the cyclodextrin by hydrogen-bonds, just another possible "intermolecular attraction" (btw, the term itself is pointless and hardly used in general).

hydroazuanacaine said:
so bonding the clonzepam to the cyclodextrine is only to make it water soluable (for the sake of dissolving it in the spray solution)? it does not increase the clonzepam's ability to cross the nasal membrane?
Click to expand...
In my understanding of the use of cyclodextrines in pharmaceutical formulations: Yes, exactly. You git it right!

Peace! Murphy
 
Well, what I was saying is that generally when you say "bond" people think about ionic or covalent bonds. This is a remnant of high school chemistry. I'm just making it clear that a new compound is not being made.
 
google the "picture" of cyclodextrin and it'll be easy to understand how a molecule goes into the "cup" xD
 
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