Hydroxypropyl-beta-cyclodextrin

Hydroxypropyl beta-cyclodextrin (HPBCD) (CAS 94035-02-6) is a partially substituted poly (hydroxypropyl) ether of beta cyclodextrin (BCD). The empirical formula is:

It contains not less than 10.0% and not more than 45.0% hydroxypropoxy (- groups. The structure is shown below where R represents either hydrogen or a hydroxypropoxy group.

The basic closed circular structure of BCD is maintained in HPBCD. The glycosidic oxygen forming the bond between the adjacent glucose monomers and the hydrogen atoms lining the cavity of the cyclodextrin impart an electron density and hydrophobic character to the cavity. Organic compounds interact with the walls of the cavity to form inclusion complexes. The hydroxyl groups and the hydroxypropyl groups are on the exterior of the molecule and interact with water to provide the increased aqueous solubility of the HPBCD and the complexes made with the HPBCD.

The hydroxypropyl groups are randomly substituted onto the hydroxyl groups of the cyclodextrin and the amount of substitution is reported as average Degree of Substitution (DS) or number of hydroxypropyl groups per cyclodextrin and is the preferred manner of describing the substitution. An alternative measurement is Molar Substitution (MS) or the average number of substitutions per anhydro glucose unit in the ring of the cylcodextrin. Molar substitution is used with polymers whose molecular weight is not determined or contains a mixture of polymers of different degrees of polymerisation.

Substitution occurs randomly with respect to which hydroxyl groups and which glucose units are modified. There is a distribution around the average degree of substitution of the number of hydroxypropyl groups per cyclodextrin, with some molecules having more than the average and some less than the average degree of substitution. The result is a mixture of many molecular species with respect to the number and location of substitutions around the ring of the cyclodextrin. The reaction to produce HPBCD is highly controllable and repeatable, so the product is consistent from batch to batch.

Substitution can have an effect on the binding of guests to the HPBCD. At low degrees of substitution, binding is very similar to that of the unmodified beta-cyclodextrin. Increasing substitution can lead to weaker binding of the guest due to steric hindrance. The effect is dependent upon the particular guest. It is even possible to obtain increased binding as a result of an increase in surface area to which the guest can bind. With most guests, these differences in binding at different degrees of substitution are small, if detectable at all.

• Improving the solubility of drugs.Insoluble drugs including Chinese herbal medicines might be turned into injections by the derivatives of cyclodextrins
  
  
• Inproving the bioavailability of drugs.For example,effectively control release oral dosing of injection of 5-fuorocarbamidopyrimidine might be prepared with an improved bioavailability,which might bring in a decreasing of the dosage but an increasing of the curative effect.On the other hand,an injection could be worked on the patients who haven't any go-aheadism.
  
  
• Adjusting or controlling the releasing of the drugs.For example,lasting effective dosings of VA,VE,VD,VK,testosterone and progesterone etc might be made with an improved stability.
  
  
• Decreasing the toxicities of the drugs.For example,to decrease the haemocylolysis of the drugs.The stimulating to eyes or nasal cavities of the related drugs cold also be decreased.
  
  
• Improving the stabilities of the drugs.For example,to prevent the volatilization,sublimation,oxidation decomposition etc.
  
  
• Concealing or rectifying the badness odor of testing.
  
  
• Inproving the synthesis effects as well as qualities of the drugs by chiral selective catalysis of cyclodextrin derivatives.It is very important for a chiral structure in drugs.
  
  
• Constructing stational chiral phases for the separation of isomers of drugs.
  
  
• Exploring molecular probes for examining differentiation of gene etc.
  
  
• Looking for new drugs or new coordination materials by more proper modifications of cyclodextrions.
  
  
• The recent work shows that HP beta CD etc could also accelerate the permeable absorption of the drugs of Testosterne etc.
  
  
• Cyclodextrin derivatives not only could play an important role in drugs and related field,but also could play an important role in cosmetics,foods and spices etc based on the structures of cyclodextrin derivatives.

Product Name:
Hydroxypropyl beta Cyclodextrin (Pharma Grade)

No.	Item	Standard Value
1	Appearance	White powder
2	Content	> = 99%
3	Water Solubility	> = 80%
4	Degree of Substitution	4-6
5	Moisture	< = 0.3%
6	PH of 1% Solution	6.8-7.2
7	Heavy Metal(as Pb)	< = 0.001%
8	Ash	< = 0.2%
9	Arsenic	< = 0.0008%
10	Sodium Chloride	< = 0.2%
11	Propylene Glycol content	< = 0.2%