Effect of thermodynamic activities of the unionized and ionized species on drug flux across buccal mucosa.

J Pharm Sci

Department of Pharmaceutics and Medicinal Chemistry, Thomas J. Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, California 95211, USA.

Published: October 2008

The objective of this work was to delineate the contribution of thermodynamic activities of ionized and unionized species on buccal drug permeation. The flux and permeability of a model acidic (nimesulide) and basic (bupivacaine) drug were determined across porcine buccal mucosa at different pH conditions. Thermodynamic activities of ionized and unionized drug species were expressed as degree of saturation (DS) and also calculated using a modified Debye-Hückel equation. Flux of model drugs across buccal mucosa depended on pH and donor chamber concentration. For saturated solution, the DS or the relative activity of the unionized species remained constant (DS(unionized) = 1) under different pH conditions. The DS of ionized species (DS(ionized)), however, increased (nimesulide) or decreased (bupivacaine) with an increase in pH, resulting in either an increased (nimesulide) or decreased (bupivacaine) flux. On the contrary, at subsaturated drug concentrations in the donor chamber, a decrease in nimesulide flux was observed with an increase in pH due to a decrease in DS(unionized). In case of a subsaturated bupivacaine solution, DS(unionized) increased with pH, thereby increasing the flux. In conclusion, thermodynamic activities of both ionized and unionized species of a drug contribute to flux across the buccal mucosa. The ionized and unionized species contributed equally to total flux when 90% of the drug was ionized.

Download full-text PDF

Source
http://dx.doi.org/10.1002/jps.21301DOI Listing

Publication Analysis

Top Keywords

thermodynamic activities
16
buccal mucosa
16
ionized unionized
16
unionized species
16
activities ionized
12
ionized species
8
species drug
8
flux
8
flux buccal
8
donor chamber
8

Similar Publications

OsMAINTENANCE OF MERISTEM LIKE 1 controls style number at high temperatures in rice.

Plant Mol Biol

January 2025

Department of Agricultural and Environmental Sciences, University of Milan, via Celoria 2, 20133, Milan, Italy.

OsMAIL1 encodes for a rice protein of the Plant Mobile Domain (PMD) family and is strongly upregulated during floral induction in response to the presence of the florigens Heading date 3a (Hd3a) and RICE FLOWERING LOCUS T1 (RFT1). Although OsMAIL1 expression depends on the florigens, osmail1 null mutants do not show delay in flowering time, rather OsMAIL1 participates in ensuring successful reproduction. Indeed, when day temperatures reach 35 °C (7 °C higher than standard greenhouse conditions), osmail1 mutants show increased sterility due to abnormal pistil development with about half of the plants developing three styles topped by stigmas.

View Article and Find Full Text PDF

Surface-active agents (surfactants) release potential energy as they migrate from one of two adjacent fluids onto their fluid-fluid interface, a process that profoundly impacts the system's energy and entropy householding. The continuum thermodynamics underlying such a surfactant-enriched binary-fluid system has not yet been explored comprehensively. In this article, we present a mathematical description of such a system, in terms of balance laws, equations of state, and permissible constitutive relations and interface conditions, that satisfies the first and second law of thermodynamics.

View Article and Find Full Text PDF

Inorganic anions such as chloride (Cl), nitrate (), sulfate (), carbonate (), bicarbonate (), dihydrogen phosphate (), fluoride (F) are ubiquitous in water matrices, play a significant role in the degradation of organic pollutants by Fenton process. In the present study, the performance of Fenton process in the presence of these anions was studied using phenol as a model compound along with the underlying mechanism and their tolerance limit. The presence of these anions affects the rate constant of the Fenton process and decreases in the following order, ---Cl >  >  >  > F.

View Article and Find Full Text PDF

Background: Microbial cholesterol oxidase (ChoX) has wide clinical and industrial applications; therefore, many efforts are being made to identify promising sources. This study aimed to isolate a novel ChoX-producing bacterial strain from whey samples.

Results: The most efficient strain was selected based on extracellular ChoX-producing ability and characterized as Escherichia fergusonii (E.

View Article and Find Full Text PDF

Single atom alloys aggregation in the presence of ligands.

Nanoscale

January 2025

Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.

Single atom alloys (SAAs) have gained tremendous attention as promising materials with unique physicochemical properties, particularly in catalysis. The stability of SAAs relies on the formation of a single active dopant on the surface of a metal host, quantified by the surface segregation and aggregation energy. Previous studies have investigated the surface segregation of non-ligated and ligated SAAs to reveal the driving forces underlying such phenomena.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!