Assessment of the Dissociation Energetics of Some Selected Ligand Drugs Bound on Human Serum Albumin by Differential Scanning Calorimetry
Journal Title: AAPS PharmSciTech - Year 2016, Vol 17, Issue 2
Abstract
Drug-protein binding may play a role in the thermal energetics of protein denaturation and could lead to the determination of its equilibrium dissociation parameter. The aim of this study was to assess the energetics of a drug that was bound to human serum albumin (HSA) during thermal denaturation. Drugs that were bound at a single high-affinity primary binding site on HSA, including diazepam and ibuprofen, were employed. Commercial HSA was treated with charcoal to remove stabilizers and adjusted to 20% w/v in a pH 7.4 buffered solution. Serial concentrations of individual drugs up to 0.16 mmole/g-protein were added to the cleaned HSA solutions whereas diazepam was added to a commercial HSA solution. Samples were subjected to differential scanning calorimetry (DSC) set to run from 37 to 90°C at 3.0°C/min. Binding of the drug slightly increased the denaturing temperature of the cleaned HSA due to a shift in the equilibrium toward the native protein bound with the drug. Diazepam depressed the denaturing temperature of the commercial HSA by competing with the stabilizers already bound to the primary site of the HSA. This yielded not only the HSA-stabilizer but also the HSA-diazepam type complexes that exhibited a different denaturation process. A rational approximation of the Lumry-Eyring protein denaturation model was used to treat the DSC endotherms. The approximated scheme: N→k3KP was successfully fitted to the data. It was used to determine the dissociation parameters for diazepam and ibuprofen bound to the HSA. These results were comparable to those obtained from other methods.
Authors and Affiliations
Damrongsak Faroongsarng
Keywords
Related Articles
- EP ID EP682170
- DOI 10.1208/s12249-015-0372-3
- Views 74
- Downloads 0
QbD-Enabled Development of Novel Stimuli-Responsive Gastroretentive Systems of Acyclovir for Improved Patient Compliance and Biopharmaceutical Performance
The online version of this article (doi:10.1208/s12249-015-0367-0) contains supplementary material, which is available to authorized users.
Roller Compaction of Hydrophilic Extended Release Tablets—Combined Effects of Processing Variables and Drug/Matrix Former Particle Size
The online version of this article (doi:10.1208/s12249-014-0219-3) contains supplementary material, which is available to authorized users.
Retraction Note: Meloxicam Taste-Masked Oral Disintegrating Tablet with Dissolution Enhanced by Ion Exchange Resins and Cyclodextrin
The online version of the original article can be found at 10.1208/s12249-013-0001-y.
Defining the Critical Material Attributes of Lactose Monohydrate in Carrier Based Dry Powder Inhaler Formulations Using Artificial Neural Networks
The study aimed to establish a function-based relationship between the physical and bulk properties of pre-blended mixtures of fine and coarse lactose grades with the in vitro performance of an adhesive active pharmaceut...
From Bench to Humans: Formulation Development of a Poorly Water Soluble Drug to Mitigate Food Effect
This study presents a formulation approach that was shown to mitigate the dramatic food effect observed for a BCS Class II drug. In vitro (dissolution), in vivo (dog), and in silico (GastroPlus®) models were deve...