Liquid membrane phenomena and drug action

Biomimetic approaches for studying membrane processes

This short review focuses on recent innovative systems and experimental approaches designed to investigate membrane processes and biomolecular interactions associated with membranes. Our emphasis is on "biomimetics" which reflects the significance and contributions of the chemistry/biology interface in addressing complex biological questions. We have not limited this review to discussion of new "sensors" or "assays"per se, but rather we tried to review new concepts employed for analysis of membrane processes.

Role of liquid membrane phenomenon in the biological actions of thioridazine

Role of surface activity in the mechanism of action of thioridazine (THR) has been studied. THR has been shown to generate liquid membrane it self and also in association with the relevant membrane lipids, sphingomyelin and cholesterol in series with a supporting membrane. Transport of relevant biogenic amines e.g. dopamine, nor-adrenaline, adrenaline, serotonin, gamma amino butyric acid (GABA) and glutamic acid and ions viz. sodium, potassium, and calcium has been studied in the presence of liquid membranes generated by THR and THE in association with sphingomyelin-cholesterol. The data on modifications in the permeability of relevant biogenic amines and ions indicate that the liquid membranes generated by THR may contribute to the mechanism of action of THR.

Role of surface activity in the biological actions of ranitidine and famotidine

The role of surface activity has been studied in the biological actions of ranitidine (RNT) and famotidine (FMT). The drugs have been shown to generate liquid membranes in series with a supporting membrane with the virtue of their amphiphilicity. Transport of histamine, acetylcholine, and ions (chloride, bicarbonate, potassium, sodium and calcium) have been studied in the presence of liquid membranes generated by surface-active RNT and FMT. The data on the modifications in the permeability of histamine, acetylcholine and ions indicate that the liquid membranes generated by RNT and FMT may play a significant role in their biological action. The surface-active nature of the drugs has been discussed with relevance to their pharmacological effects.

Transport across liquid membranes containing vitamin A (retinol acetate)

The role of the surface activity of vitamin A has been studied in the light of the liquid membrane hypothesis of drug action. Transport of relevant amino acids such as serine, threonine, arginine, and histidine and various ions such as calcium, sodium, and potassium in the presence of liquid membranes generated by vitamin A has been studied. The data on the modifications in the permeability of relevant amino acids and ions indicate that the liquid membranes generated by vitamin A may also play a significant role in its physiological action.

Thiazine, antibiotic, bilirubin adducts

1. Electron charge transfer interactions of some phenothiazine derivatives with aminoglycoside antibiotics, beta-lactams and penicillin-related antibiotics and bilirubin were investigated with alternating current titrations. 2. Neither the beta-lactams nor penicillin-related drugs interacted. 3. However, the aminoglycoside antibiotics formed complexes with the phenothiazines. 4. Tobramycin and gentamicin each formed 1:2 adducts with carbenicillin. 5. The phenothiazines interacted with bilirubin forming concentration-dependent micellar adducts which were exciplexes. This may explain the appearance of xanthomata in patients medicated with phenothiazines.