Separation of neutral dihydropyridines and their enantiomers using electrokinetic chromatography.

The separation and simultaneous enantiomeric separation of three neutral 1,4-dihydropyridine (DHP) derivatives (nimodipine, nisoldipine and nitrendipine) was studied using electrokinetic chromatography. Bile salts allowed the non-chiral separation of these DHP derivatives. With the taurine-conjugated bile salts a beginning of enantiomeric separation was observed for nimodipine and nisoldipine.

Influence of methanol on the enantioresolution of antihistamines with carboxymethyl-beta-cyclodextrin in capillary electrophoresis.

According to the model of Wren and Rowe, the separation between two enantiomers in capillary electrophoresis (CE) decreases if an organic modifier is added to the run buffer containing a neutral cyclodextrin (CD) in a concentration below its optimal value in a solvent-free system. In previous work, however, it was observed that the addition of methanol to the background electrolyte (BGE) containing not charged carboxymethyl-beta-CD in a concentration below its optimal value, increased the enantioresolution of dimetindene maleate. The enantioresolution decreased when other organic modifiers (ethanol, isopropanol or acetonitrile) were added and/or when other neutral (beta-CD, hydroxypropyl-beta-CD) or chargeable (carboxyethyl-beta- and succinyl-beta-CD) CDs were used.

Differential effects of organic modifiers on the enantioseparation of dimetindene maleate with carboxymethyl-beta-cyclodextrin in capillary electrophoresis.

Methanol enhances the enantioresolution of dimetindene enantiomers with carboxymethyl-beta-cyclodextrin (CMCD) as chiral selector at a concentration below its optimal value. The same effect was observed with ethanol (EtOH), although less pronounced. On the other hand, the addition of isopropanol (IP) or acetonitrile (ACN) decreases the enantioseparation.

Development of a validated capillary electrophoresis method for enantiomeric purity testing of dexchlorpheniramine maleate.

A capillary zone electrophoresis method has been developed for the detection of 0.1% of (R)-levochlorpheniramine maleate in samples of (S)-dexchlorpheniramine maleate. Using 1.

Preparation of beta-artemether liposomes, their HPLC-UV evaluation and relevance for clearing recrudescent parasitaemia in Plasmodium chabaudi malaria-infected mice.

Egg phosphatidylcholine-cholesterol liposome formulations containing the antimalarial drug beta-artemether have been prepared and analyzed for their encapsulating capacity, chemical stability, leakage, in vitro release and their therapeutic efficiency against Plasmodium chabaudi infection. A HPLC-UV analysis of beta-artemether liposomes without derivatisation was achieved. A good linearity of y=4437.