Name: Hydroxypropyl Betadex
CAS No: b-Cyclodextrin, 2-hydroxypropyl ether [94035-02-6] and [128446-35-5]
BP: Hydroxypropylbetadex PhEur: Hydroxypropylbetadex USP-NF: Hydroxypropyl Betadex
Cavasol W7; 2-hydroxypropyl-b-cyclodextrin; 2-hydroxypropyl cyclomaltoheptaose; hidroksipropilbetadeksas; hydoxipropylbetadex; hydroksipropylbetadeksi; hydroxypropylbetadeksum; hydroxypropylbetadexum; Kleptose HPB.
b-Cyclodextrin, 2-hydroxypropyl ether [94035-02-6] and [128446-35-5]
C42H70O35(C3H6O)x(where x = 7 molar substitution) The molecular weight depends on the degree of substitution. The molecular weight of unsubstituted b-cyclodextrin is 1134.98.
Hydroxpropyl betadex is a partially substituted ether of bcyclodextrin. USP32–NF27 requires that the molar substitution is between 0.4 and 1.5 hydroxypropyl groups per anhydroglucose unit.
Hydroxypropyl betadex has been widely investigated in pharmaceutics and has principally been used as a solubilizer for hydrophobic molecules in oral liquids,(1,2) oral solids,(3) parenterals,(4,5) pressurized metered dose inhalers,(6) dry powder inhalers,(7) and topical formulations.(8) It has also been shown to act as a stabilizer during processing(9) and storage of formulations.(10) Hydroxypropyl betadex inclusion complexes have been reported to show mechanical properties distinct from the pure materials.(11) The reported advantage of hydroxypropyl betadex over unsubstituted b-cyclodextrin is its greater water solubility.(3)
Hydroxypropyl betadex occurs as a white or almost white, amorphous or crystalline powder.
See Table I.
Acidity/alkalinity pH = 5–8 of a 20 g/L solution at 208C for Cavasol W7 HP Pharma Density (bulk) 0.4 g/cm3 for Cavasol W7 HP; 0.2–0.3 g/cm3 for Cavasol W7 HP Pharma. Ignition temperature 4208C for Cavasol W7 HP; >4008C for Cavasol W7 HP Pharma. Melting point 2788C; 120–1608C for Cavasol W7 HP Specific rotation [a]D 25 = þ1408 to þ1458 Solubility Freely soluble in water and propylene glycol. Soluble in ethanol, methanol, dimethyl sulfoxide and dimethylformamide. 2300 g/L water solubility at 248C for Cavasol W7 HP; 2300 g/L water solubility at 258C for Cavasol W7 HP Pharma. Water content Typically <3.0%.
Store in well-closed containers.
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Hydroxypropyl betadex is prepared by the treatment of an alkaline solution of b-cyclodextrin with propylene oxide. The substitution pattern can be influenced by varying the pH. Formation of O-6 and O-2 substituted products is favored by high and low alkali concentration, respectively. The mixture of products produced may be refined by preparative chromatography.(12)
The pharmaceutical toxicology of hydroxypropyl betadex has been reviewed,(13) and in general, the material was found to be of low toxicity. It has been suggested that hydroxypropyl betadex may have a synergistic toxic effect with, for example, carcinogens, by increasing their solubility and thus bioavailability.(14)
Observe normal precautions appropriate to the circumstances and quantity of the material handled.
Included in oral and parenteral medicinal products. Included in an injectable preparation licensed in the UK for intramuscular or intravenous administration.
Cyclodextrins; 3-hydroxypropyl-b-cyclodextrin; sulfobutylether bcyclodextrin 3-Hydroxypropyl-b-cyclodextrin Synonyms 2-HP-b-CD. Appearance White crystalline powder. Solubility Greater than 1 in 2 parts of water at 258C. Surface tension 70.0–71.0mN/m (70–71 dynes/cm) at 258C. Comments Used in applications similar to those for b-cyclodextrin. However, as it is not nephrotoxic it has been suggested for use in parenteral formulations. The degree of substitution of hydroxypropyl groups can vary.
Hydroxypropyl betadex has been investigated as an absorption (permeation) enhancer in oral,(15) transdermal,(16) and nasal(17) systems. It was found to be effective in increasing penetration in some studies, although the mechanism of action may be compound specific.