Abstract
Knowledge about the release behavior and drug retention properties of colloidal carriers is of essential importance for quality control as well as to predict in vivo performance. When conducting release studies from such systems, the release media should preferentially contain lipophilic acceptor components in order to mimic physiological conditions. In this study, transfer from a trimyristin nanoemulsion into lipid-containing hydrogel beads was investigated for fenofibrate, cannabidiol, retinyl acetate, orlistat, and lumefantrine. To generate the acceptor system, a trimyristin nanoemulsion was incorporated into Ca-alginate microspheres (mean diameter ~40 µm) with a spraying method. Using this approach, the advantages of small lipophilic acceptor particles with a large interfacial area were combined with a single separation process from the donor via a filtration step. The method was applicable to distinguish between fast (fenofibrate) and slow drug transfer (lumefantrine) with good time resolution. Lipophilicity, estimated according to the calculated logP value of the respective drug, was a major factor influencing the transfer performance: the higher the logP value, the slower the transfer. This experimental setup is a promising technique to investigate the release of poorly water-soluble drugs from various types of nanocarriers under closer to physiological conditions than with many other methods currently applied.
Highlights
Colloidal lipid dispersions are being investigated as a promising formulation approach for the parenteral administration of poorly water-soluble drugs as they combine good bioavailability with low toxicity [1]
The trimyristin-containing hydrogel particles could be applied successfully to investigate the transfer of drugs with different lipophilicities from lipid nanoemulsions
The enclosure of trimyristin nanodroplets was a simple approach to mimic lipophilic compounds present in the bloodstream and created an experimental setup which is closer to physiological (i.v.) conditions than with most other release media currently applied
Summary
Colloidal lipid dispersions are being investigated as a promising formulation approach for the parenteral (especially i.v.) administration of poorly water-soluble drugs as they combine good bioavailability with low toxicity [1]. In order to rationally design colloidal drug carrier formulations, it is of essential importance to obtain information on their drug retention and release characteristics which can be used as quality control criteria as well as to predict in vivo behavior. No standard regulatory in vitro release test is available for nanoparticulate systems. Complete separation of the nanoparticulate drug carrier system from the released drug, as performed via ultrafiltration or centrifugation, may not always be possible. Drug release may continue during the separation process. This leads to an insufficient time resolution which may provoke distorted results [2,3,4,5]. Continuous flow methods as outlined, e.g., by D’Souza and DeLuca, are modifications of the standardized Apparatus 4 described in the United
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
