Transport Properties for Pharmaceutical Controlled-Release Systems: A Brief Review of the Importance of Their Study in Biological Systems

Abstract

The goal of this work was to comprehensive study the transport properties of controlled-release systems for the safe and reliable delivery of drugs. Special emphasis has been placed on the measurement of the diffusion of drugs, alone or in combination with carrier molecules for enhanced solubility and facilitated transport. These studies have provided detailed comprehensive information—both kinetic and thermodynamic—for the design and operation of systems for the controlled release and delivery of drugs. Cyclodextrins are among the most important carriers used in these systems. The basis for their popularity is the ability of these materials to solubilize poorly soluble drugs, generally resulting in striking increases in their water solubilities. The techniques used in these investigations include pulse voltammetry, nuclear magnetic resonance (NMR) and Raman spectroscopy, ultrasonic relaxation, and dissolution kinetics. Transport in these systems is a mutual diffusion process involving coupled fluxes of drugs and carrier molecules driven by concentration gradients. Owing to a strong association in these multicomponent systems, it is not uncommon for a diffusing solute to drive substantial coupled fluxes of other solutes, mixed electrolytes, or polymers. Thus, diffusion data, including cross-diffusion coefficients for coupled transport, are essential in order to understand the rates of many processes involving mass transport driven by chemical concentration gradients, as crystal growth and dissolution, solubilization, membrane transport, and diffusion-limited chemical reactions are all relevant to the design of controlled-release systems. While numerous studies have been carried out on these systems, few have considered the transport behavior for controlled-release systems. To remedy this situation, we decided to measure mutual diffusion coefficients for coupled diffusion in a variety of drug–carrier solutions. In summary, the main objective of the present work was to understand the physical chemistry of carrier-mediated transport phenomena in systems of controlled drug release.

Diffusivity of α-, β-, γ-cyclodextrin and the inclusion complex of β-cyclodextrin: Ibuprofen in aqueous solutions; A molecular dynamics simulation study

“…In most of these studies, the stability of the host-guest complex is studied by using either experimental or simulation techniques [5] , [18] , [20] , [23] , [24] , [25] , [26] , [27] , [28] , [29] . Although in various applications of CDs such as controlled drug-delivery [24] , [30] , [31] , [32] mass transport can play an important role, it has not been as widely studied as the binding properties of the inclusion complexes.…”

Utilization of dairy beta stream to produce phospholipids products by salt precipitation and solvent fractionation

“…As discussed in the earlier section, PLs in MFGM are associated with membrane proteins. For dissolution of PLs to occur, the inter‐particulate bonds, which hold PLs and membrane protein together, need to be broken, and affinity between PLs and solvent needs to be formed (Radivojev et al, 2019; Ribeiro & Esteso, 2018). Hence, increased temperature resulted in enhanced PLs concentration with 90% ethanol extraction (Price et al, 2020), because heat provided the energy to break the bonds between protein and PLs.…”

Drug Delivery Systems: Study of Inclusion Complex Formation between Methylxanthines and Cyclodextrins and Their Thermodynamic and Transport Properties

“…Diffusion is an important irreversible process taking place as a result of a gradient of concentration inside the solution [38,39]. Its quantitative measure can be done through the diffusion coefficient of each species in solution [40].…”