Effect of Food Viscosity on Drug Dissolution

• Published in: Pharmaceutical research 2024, Vol.41 (1), p.105-112
• Main Authors: Hirose, Rika, Sugano, Kiyohiko
• Format: Article
• Language: English
• Subjects: Benzocaine; Biochemistry; Biomedical and Life Sciences; Biomedical Engineering and Bioengineering; Biomedicine; Cellulose; Diffusion coefficient; Dissolution; Drug Liberation; Mass transfer; Medical Law; Methylcellulose; Original Research Article; Pepsin; Pepsin A; Pharmacology/Toxicology; Pharmacy; Sucrose; Viscosity; Water
• ISSN: 0724-8741; 1573-904X
• DOI: 10.1007/s11095-023-03620-y

Purpose The purpose of the present study was to investigate the effect of food viscosity on the dissolution rate of a drug. There are two types of viscosity, macroviscosity and microviscosity. Macroviscosity affects the diffusion layer thickness, whereas microviscosity affects the molecular diffusion coefficient. The mass transfer coefficient ( k c ) in the intrinsic dissolution rate (IDR) depends on the viscosity ( η ) as k c  ∝ η a ( a is an exponent on η ). In theory, for rotating flow over a disk, if a thickener increases only macroviscosity, a  = -1/6, and if it increases both macroviscosity and microviscosity equally, a  = -7/6. Method Benzocaine was used as a model drug. Hydroxypropyl cellulose (HPC) and methylcellulose (MC) were employed as control thickeners that increase only macroviscosity. Sucrose was employed as a control thickener for both macroviscosity and microviscosity. The FDA breakfast homogenate (BFH) was diluted with distilled water or 1 mM HCl with/without pepsin digestion. The IDR value was measured by the paddle-over-disk method. Results The η value of 30% BFH distilled water was 209 mPa∙s, about 300 times higher than distilled water. It was further increased by HCl (430 mPa∙s), and reduced by pepsin digestion (35 mPa∙s). The k c value was little affected by BFH ( a  = 0.00 to -0.09), slightly less than those in HPC ( a  = -0.19) and MC ( a  = -0.21). Sucrose decreased the k c value more significantly (a = -0.70). Conclusion The IDR and k c values of benzocaine were little affected by BFH, suggesting that BFH increased only macroviscosity.