Skip to Main Content
 

Global Search Box

 
 
 
 

Files

ETD Abstract Container

Abstract Header

Investigating Colloidal Domains of Emulsion- and Gel-Type Formulations Using Neutron Scattering Techniques

Abstract Details

2021, PhD, University of Cincinnati, Pharmacy: Pharmaceutical Sciences.
Micellar, microemulsion, and gel systems are frequently used in personal care products to achieve the desired rheological, aesthetic, and cleansing properties. Surfactants are frequently used in these products and self-assemble with non-covalent interactions (e.g. hydrogen bonding, van der Waals forces) to form micellar systems and, when combined with oil and a co-surfactant, microemulsions. Gelators assemble into networks that trap solvent, making them excellent thickeners. Depending on the gelator’s molecular structure, the monomers can assemble covalently or, like surfactants, with non-covalent interactions. Systems that self-assemble via non-covalent interactions can be sensitive to various aspects of the formulation, such as the presence of salt, the ratio of solvent to surfactant or gel, and the solvent properties. Systematically studying the effects of various additives on the self-assembly of surfactants and gels is valuable to learn how to effectively tune the properties of these systems to maximize the release of actives and improve product performance. Sodium trideceth-2 sulfate and sodium laureth-1 and -3 sulfate were studied as individual primary surfactants while cocamidopropyl betaine was included as a cosurfactant to create three different mixed-surfactant systems. Dipropylene glycol (DPG, cosolvent) and two perfume mixtures consisting of 3 or 12 perfume raw materials (PRMs), spanning a range of log P values and molecular structures, were added to each mixed-surfactant system to study their effects on the surfactant self-assembly and release of perfumes into the headspace. The effect of dilution with water was also investigated to simulate rinse-off situations. Changes to the self-assemblies of two low-molecular weight gels (LMWGs) were studied as a function of gel concentration, the presence of carbamazepine, and sonication. Small-angle neutron scattering, gas-chromatography mass-spectrometry, nuclear magnetic resonance, microscopy, and statistics were used to study the geometry of the self-assemblies, release of perfume in the headspace, and the interactions between the monomers and localization of perfume. The surfactant tail structure in a formulation influences the localization of an active inside the self-assembly. The surfactant molecular structure and concentrations of perfume accord and DPG were key parameters influencing the geometry and size of the surfactant self-assembly. The headspace concentration for each PRM in the perfume accord was affected by the perfume accord composition, the PRM's log P value, the concentrations of other components like DPG in the system, the oil:water ratio in the system, the PRM's molecular structure, the surfactant tail structure and micelle dimensions and volume fraction. The perfume accord composition was important in the formation of Winsor IV type microemulsions and how much they can be diluted before they change type. For LMWG gel systems, the gelator concentration, the active ingredient concentration, the compatibility between the active’s molecular structure and the gelator’s, and the energy input into the system via sonication all influenced the speed at which the gel structure matured and the overall structure of the gel network. This further affected the rheological properties and strength of the bulk gel. Finally, suggestions on how to improve actives delivery and product effectiveness, and directions for future work in this field were provided.
Harshita Kumari (Committee Chair)
Kavssery Ananthapadmanabhan (Committee Member)
Thomas Beck, Ph.D. (Committee Member)
Kevin Li, Ph.D. (Committee Member)
Edward Smith, III (Committee Member)
364 p.

Recommended Citations

Citations

  • Mirzamani, M. (2021). Investigating Colloidal Domains of Emulsion- and Gel-Type Formulations Using Neutron Scattering Techniques [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1623167085524348

    APA Style (7th edition)

  • Mirzamani, Marzieh. Investigating Colloidal Domains of Emulsion- and Gel-Type Formulations Using Neutron Scattering Techniques. 2021. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1623167085524348.

    MLA Style (8th edition)

  • Mirzamani, Marzieh. "Investigating Colloidal Domains of Emulsion- and Gel-Type Formulations Using Neutron Scattering Techniques." Doctoral dissertation, University of Cincinnati, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1623167085524348

    Chicago Manual of Style (17th edition)