<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>Drugs remain for a short time on mucus membranes, such as oral, ocular, or nasal mucus, which are washed with physiological fluids. One of the possibilities to overcome this obstacle is the application of solutions that, due to the physiological environment or stimulus, turn into more viscous gels. These gels often also have mucoadhesive properties and the drug is released from them for a longer period. Carbomer 940 (C940), polycarbophil (PCP), and chitosan (CH) are gel-forming excipients, and the consistency of their solutions changes due to the concentration of protons (pH); therefore, they are referred to as pH-sensitive gelling agents. The aim of this study was to prepare pH-sensitive solutions that form gels in the pH of the oral cavity. We prepared water solutions with various concentrations of gel-forming excipients and evaluated the appearance, pH of the solution, injectability of the solution, and pH of gelation. By determining the pH of gelation, suitable concentrations (w/w) of the used polymers were found, namely, 0.1% C940, 0.225% PCP, and 2.5% CH with medium molecular weight (CHM). The 0.1% C940 and 0.225% PCP solutions were injectable through the syringe with the smallest 0.5 mm needle diameter. The 2.5% CHM solution was not injectable even through the syringe with the largest 0.8 mm needle diameter. Solgels prepared at the determined concentrations were evaluated by a dissolution test in a pH 6.8 phosphate buffer using methylene blue (MB) as a model substance. After 60 min of dissolution, 77.04% ± 5.94%, 48.85% ± 5.74%, and 77.35% ± 4.98% of MB were released from samples with C940, PCP, and CHM, respectively. The dissolution of the C940 and CHM samples took place according to the Korsmeyer–Peppas kinetic model (R2 0.999 ± 0.001, 0.978 ± 0.003) and of the PCP samples took place according to the first-order model (R2 0.994 ± 0.001). The 0.225% PCP pH-sensitive gel showed the most advantageous properties in terms of injectability, pH gelation, and prolonged release of MB.</p>
</abstract>

Drugs remain for a short time on mucus membranes, such as oral, ocular, or nasal mucus, which are washed with physiological fluids. One of the possibilities to overcome this obstacle is the application of solutions that, due to the physiological environment or stimulus, turn into more viscous gels. These gels often also have mucoadhesive properties and the drug is released from them for a longer period. Carbomer 940 (C940), polycarbophil (PCP), and chitosan (CH) are gel-forming excipients, and the consistency of their solutions changes due to the concentration of protons (pH); therefore, they are referred to as pH-sensitive gelling agents. The aim of this study was to prepare pH-sensitive solutions that form gels in the pH of the oral cavity. We prepared water solutions with various concentrations of gel-forming excipients and evaluated the appearance, pH of the solution, injectability of the solution, and pH of gelation. By determining the pH of gelation, suitable concentrations (w/w) of the used polymers were found, namely, 0.1% C940, 0.225% PCP, and 2.5% CH with medium molecular weight (CHM). The 0.1% C940 and 0.225% PCP solutions were injectable through the syringe with the smallest 0.5 mm needle diameter. The 2.5% CHM solution was not injectable even through the syringe with the largest 0.8 mm needle diameter. Solgels prepared at the determined concentrations were evaluated by a dissolution test in a pH 6.8 phosphate buffer using methylene blue (MB) as a model substance. After 60 min of dissolution, 77.04% ± 5.94%, 48.85% ± 5.74%, and 77.35% ± 4.98% of MB were released from samples with C940, PCP, and CHM, respectively. The dissolution of the C940 and CHM samples took place according to the Korsmeyer–Peppas kinetic model (R2 0.999 ± 0.001, 0.978 ± 0.003) and of the PCP samples took place according to the first-order model (R2 0.994 ± 0.001). The 0.225% PCP pH-sensitive gel showed the most advantageous properties in terms of injectability, pH gelation, and prolonged release of MB.

Pilot Formulation Study of Ph-sensitive Gels

Department of Pharmaceutical Technology, Pharmacognosy and Botany

University of Veterinary Medicine and Pharmacy in Košice

European Pharmaceutical Journal

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

{"article-title":"Pilot Formulation Study of Ph-sensitive Gels"}

Drugs remain for a short time on mucus membranes, such as oral, ocular, or nasal mucus, which are washed with physiological fluids. One of the possibilities to...

Pilot Formulation Study of Ph-sensitive Gels

Article Category: Special Issue Article

Publicado en línea: 24 ago 2023

Páginas: 28 - 33

Recibido: 14 jun 2023

Aceptado: 23 jun 2023

DOI: https://doi.org/10.2478/afpuc-2023-0005

Palabras clave
in situ, pH-sensitive, gel, polycarbophil, chitosan, carbomer 940

© 2023 T. Wolaschka et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Pilot Formulation Study of Ph-sensitive Gels

Article Category: Special Issue Article

Publicado en línea: 24 ago 2023

Páginas: 28 - 33

Recibido: 14 jun 2023

Aceptado: 23 jun 2023

DOI: https://doi.org/10.2478/afpuc-2023-0005

Palabras clavein situ, pH-sensitive, gel, polycarbophil, chitosan, carbomer 940

© 2023 T. Wolaschka et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Palabras clave
in situ, pH-sensitive, gel, polycarbophil, chitosan, carbomer 940