How to maximize encapsulation efficiency of a drug in cyclodextrins, particularly B-CD and Y-CD?
Dear herein I will answer you based on beta-cyclodextrin, if you understand this rest all will be easy.
1. Beta-cyclodextrin has hydrophilic shell and hydrophobic core. But is water soluble. This can be used to incorporate hydrophobic drug in its core and increase the solubility-permeability of drug. However concentration of beta cyclodextrin you are using to incorporate your drug is also important. If you use excessive cyclodextrin there may be problem, in drug release or ur drug release from system will be greatly extended.
2. At first you choose weight by weight ratio for eg. 1:1 cyclodextrin:drug; 2:1; 3:1; 4:1, 5:1 respectively. While incorporating, cyclodextrin can be dissolved in water, for hydrophobic drug use organic solvent. In rotary evaporator, keep cyclodextrin and evaporate it and add drug solution in organic solvent and evaporate it too, now reconstitute it in water and freeze dry it. Perform same with different weight ratios. After you obtain various tubes of cyclodextrin+drug complex, do saturated solubility studies. Herein keep a drug in eppendorf tube add known amount of water and rotate + sonicate after a fixed duration, centrifuge and measure solubility, the one with highest solubility you select but note the result of all.
3. One thing you keep in mind, if you further want to incorporate your cyclodextrin + drug complex in nanoemulsion, again you should be careful on ur weight ratio, as excessive cyclodextrin wont dissolve greatly in oil phase due to its polarity herein you have to produce w/o/w.
Hi Miguel,
Usually, the kneading method provides the highest ee, though removing the uncomplexed guest is always a challenge. A common misbelief is that if you prepare a complex by kneading, the solid will contain only the complex. Please remember also the dissolution necessarily results in dissociation (dynamic equilibrium), especially when the apparent complex stability constant is low.
In a lucky case, you can remove the uncompleted guest with an organic solvent (CH2Cl2, MeOH, or acetone). Please note there are organic solvents (e.g., alcohols other than MeOH) that can form complexes with CDs.
Good luck,
Laszlo
Encapsulation efficiency refers to the amount of drug that is successfully entrapped within the cyclodextrin cavity. To maximize EE, several factors should be considered:
Overall, selecting the appropriate cyclodextrin, optimizing the molar ratio of cyclodextrin to drug, and carefully controlling the preparation conditions can help maximize the encapsulation efficiency of a drug in cyclodextrins.
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