title: Mathematical modeling of surface-active and non-surface-active drug transport in emulsion systems.
abstract: Mathematical models were developed for the prediction of surface-active and non- surface-active drug transport in triphasic (oil, water, and micellar) emulsion systems as a function of micellar concentration. These models were evaluated by comparing experimental and simulated data. Fick's first law of diffusion with association of the surface-active or complexation nature of the drug with the surfactant was used to derive a transport model for surface-active drugs. This transport model assumes that the oil/water (O/W) partitioning process was fast compared with membrane transport and therefore drug transport was limited by the membrane. Consecutive rate equations were used to model transport of non-surface-active drugs in emulsion systems assuming that the O/W interface acts as a barrier to drug transport. Phenobarbital (PB) and barbital (B) were selected as surface-active model drugs. Phenylazoaniline (PAA) and benzocaine (BZ) were selected as non- surface-active model drugs. Transport studies at pH 7.0 were conducted using side-by-side diffusion cells and bulk equilibrium reverse dialysis bag techniques. According to the surface-active drug model, an increase in micellar concentration is expected to decrease drug-transport rates. Using the Microsoft EXCEL program, the non-surface-active drug model was fitted to the experimental data for the cumulative amount of the model drug that disappeared from the donor chamber. The oil/continuous phase partitioning rates (k1) and the membrane transport rates (k2) were estimated. The predicted data were consistent with the experimental data for both the surface-active and non- surface-active models.
authors.affiliation: Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT 06269, USA. nac93002@uconnvm.uconn.edu
authors.forename: N
authors.initials: N
authors.lastname: Chidambaram
authors.forename: D J
authors.initials: DJ
authors.lastname: Burgess
mesh_terms: D000465:Algorithms; D001462:Barbital / Q000737:chemistry; D001566:Benzocaine / Q000737:chemistry; D001692:Biological Transport; D002412:Cations; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D003956:Dialysis / Q000295:instrumentation; D004058:Diffusion; D004655:Emulsions; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008823:Micelles; D008899:Mineral Oil; D008954:Models, Biological; D004364:Pharmaceutical Preparations / Q000737:chemistry* / Q000378:metabolism; D010634:Phenobarbital / Q000737:chemistry; D010938:Plant Oils / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*; D014867:Water; D010128:p-Aminoazobenzene / Q000737:chemistry
chemical_list: D002412:Cations; D002593:Cetrimonium Compounds; D004655:Emulsions; D008823:Micelles; D004364:Pharmaceutical Preparations; D010938:Plant Oils; D013501:Surface-Active Agents; D014867:Water; D011092:Polyethylene Glycols; D010128:p-Aminoazobenzene; D001462:Barbital; D008899:Mineral Oil; C033084:polyethylene glycol oleyl ether; D001566:Benzocaine; D010634:Phenobarbital; D000077286:Cetrimonium