Effect of hydrophilic/lipophilic balance on the porogenic properties of non-ionic surfactants for monolith preparation and chromatographic separation

Fotouh R Mansour; Emily F Hilder; Faisal K Algethami; Taghrid Alomar; R Dario Arrua

doi:10.1016/j.chroma.2023.463991

Effect of hydrophilic/lipophilic balance on the porogenic properties of non-ionic surfactants for monolith preparation and chromatographic separation

J Chromatogr A. 2023 Jun 21:1699:463991. doi: 10.1016/j.chroma.2023.463991. Epub 2023 Apr 13.

Authors

Fotouh R Mansour¹, Emily F Hilder², Faisal K Algethami³, Taghrid Alomar⁴, R Dario Arrua²

Affiliations

¹ Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Tanta University, Tanta, Egypt; Australian Centre for Research on Separation Science (ACROSS), University of Tasmania, Tasmania, Australia. Electronic address: fotouhrashed@pharm.tanta.edu.eg.
² Australian Centre for Research on Separation Science (ACROSS), University of Tasmania, Tasmania, Australia; Future Industries Institute, University of South Australia, Mawson Lakes Campus, Adelaide SA 5095, Australia.
³ Chemistry Department, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), P.O. Box 90905, Riyadh, 11623, Kingdom of Saudi Arabia.
⁴ Department of Chemistry, College of Science, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia.

PMID: 37104946
DOI: 10.1016/j.chroma.2023.463991

Abstract

The effect of hydrophilic/lipophilic balance (HLB) of polyoxyethylene ethers of different chain lengths on the microporogenic properties of the Brij surfactants has been studied. The objective of this work is to help better understand the role of each porogen and to set criteria for selecting the proper non-ionic surfactant, based on the HLB value. Seven recipes of different porogen compositions were first prepared and the highest efficiency was achieved using decane/decanol/dodecanol mixture with Brij® 30. Then, four other Brij surfactants covering the entire HLB scale were tested, and the prepared monoliths were characterized by SEM, BET, FT-IR and chromatography. The results showed that increasing the HLB from 9.72 to 18.84 was accompanied by an increase in monolith density and surface areas. The optimum HLB range was found to be 10 to 15. Surfactants of lower HLB formed either nonporous or less efficient columns, while those of higher HLB formed non-permeable columns. Adjusting the HLB was possible by mixing surfactants of different HLB. The prepared monoliths could be used in the isocratic mode with a mobile phase consisting of a mixture of ACN and water (20:80, v/v) at a flow rate of 1.5 μL min^-1 to separate five sulfa drugs. The separation results showed that the elution order of the compounds correlated with their lipophilicity, with sulfamerazine (logp = 0.52) being the first to elute, and sulfaquinoxoline (logp=1.70) being the most retained. The asymmetry factors of the separated compounds ranged between 1.18 and 1.25, and the resolution was found to be in the range 2.92-7.80. The prepared monoliths could be also successfully separate a mixture of four different nonsteroidal anti-inflammatory drugs and a mixture of four benzoic acid derivatives. This work assists in optimizing the surfactant-based porogenic mixture to meet the desired porosity, surface area, morphology and chromatographic separation requirements.

Keywords: Hydrophilic/Lipophilic Balance; Liquid Chromatography; Monolith; Porogen; Surfactant.

MeSH terms

Chromatography, Reverse-Phase* / methods
Hydrophobic and Hydrophilic Interactions
Porosity
Spectroscopy, Fourier Transform Infrared
Surface-Active Agents*

Substances

Surface-Active Agents