Emulsions, foams and fragrance design in skin cleansing formulations: Review and innovations

This presentation will review oil based emulsions and micro emulsions developed for personal care applications and highlight key trends and innovations in this field. The main function of emulsions is to provide moisturization, occlusion or conditioning benefits to substrates such as skin or hair. A key challenge has been understanding and optimizing the factors effecting the stability of emulsion droplets from destabilization mechanisms such as sedimentation/creaming, flocculation, coalescence, and tolerance to temperature and freeze thaw cycles under equilibrium and kinetic conditions. The presentation focuses on suspension stability of ester or petrolatum based emulsion droplets achieved by an acrylates copolymer, namely SurfaThix-N, in combination with vegetal amphiphilic molecules called ProLipids carefully selected to form lamellar gels that mimic the skin’s natural ordered lamellar lipid bilayer. The key functionality of enhancing the benefits of cosmetic bio actives delivered to skin and providing skin barrier protection during use will be discussed

A national survey of valganciclovir dosing strategies in pediatric organ transplant recipients

PurposeData remain limited on the most appropriate valganciclovir (VGCV) dosing strategy for cytomegalovirus (CMV) prophylaxis and treatment in pediatric organ transplant recipients. Therefore, the objective of this study was to describe methods used to calculate VGCV dosing among pediatric transplant centers.MethodsA survey of pharmacists was conducted to assess VGCV dosing strategies for CMV prophylaxis and treatment among pediatric organ transplant centers in the U.S.FindingsOf 54 centers that perform pediatric organ transplants, 22 (40.7%) centers responded to the survey. Fourteen centers (53.8%) utilize the Food and Drug Administration (FDA) recommended VGCV dosing strategy of 7 à  body surface area (BSA) à  creatinine clearance (CrCl) for CMV prophylaxis. Other dosing strategies reported included weight based and 520 mg/m2 à  BSA per day. Dosing strategies of VGCV for the treatment of CMV also differed across centers, with a majority (43.5%) using 7 à  BSA à  CrCl twice daily.ConclusionLess than twoâ thirds of centers utilize the FDAâ approved daily dosing regimen with various methods of CrCl calculation and serum creatinine assay measurements used. More retrospective and prospective studies with clinical outcomes associated with VCGV dosing strategies are warranted to determine the most appropriate prophylaxis and treatment strategies for CMV.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146489/1/ctr13369.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146489/2/ctr13369_am.pd

Interaction of the nonionic surfactant C12E8 with high molar mass poly(ethylene oxide) studied by dynamic light scattering and fluorescence quenching methods

Dynamic light scattering has been used to investigate ternary aqueous solutions of n-dodecyl octaoxyethylene glycol monoetber (C12E8) with high molar mass poly(ethylene oxide) (PEO). The measurements were made at 20 °C, always below the cloud point temperature (Tc) of the mixed solutions. The relaxation time distributions are bimodal at higher PEO and surfactant concentrations, owing to the preacute of free surfactant micelles, which coexist with the slower component, representing the polymer coil/micellar cluster comptex. As the surfactant concentration is increased, the apparent hydrodynamic radius (RH) of the coil becomes progressively larger. It is suggested that the complex structure consists of clusters of micelles sited within the polymer coil, as previously concluded for the PEO-C12E8-water system. However. C12E8 interacts less strongly than C12E8 with PEO; at low concentrations of surfactant the complex does not contribute significantly to the total scattered intensity. The perturbation of the PEO coil radius with C12E8 is also smaller than that in the C12E8 system. The addition of PEO strongly decreases the clouding temperature of the system, as previously observed for C12E8/PEO mixtures in solution Addition of PEO up to 0.2% to C12E8 (10 wt %) solutions doss not alter the aggregation number (Nagg) of the micelles probably because the surfactant monomers are equally partitioned as bound and unbound micelles. The critical micelle concentration (cmc), obtained from the I1/I3 ratio (a measure of the dependence of the vibronic band intensities on the pyrene probe environment), does not change when PEO is added, suggesting that for neutral polymer/surfactant systems the trends in Nagg and the cmc do not unambiguously reflect the strength of interaction

Salt-induced sphere-to-disk transition of octadecyltrimethylammonium bromide micelles

We have used surface tension measurements, differential scanning calorimetry (DSC), dynamic light scattering (DLS), and cryo-transmission electron microscopy (cryo-TEM) to investigate the dynamic and structural behavior of octadecyltrimethylammonium bromide (C(18)TAB) micelles in water and NaBr solution. The surface tension data for fixed C(18)TAB concentrations of 25 mM and varied NaBr additions (0-50 mM) shows that the critical micelle concentration (cmc) increases after an initial decrease at 0.5 mM NaBr. This unusual effect has been explained using results from DSC and DLS. At low salt concentrations (below ca. 25 mM) the relaxation time distribution is bimodal with a dominant fast mode due to spherical micelles. Above ca. 35 mM NaBr disklike structures are favored and the relaxation time distribution is more closely unimodal. The postulated sphere-to-disk transition is supported by cryo-TEM micrographs. A pronounced increase in the micellar effective hydrodynamic radius (R-H) is observed as the NaBr concentration is increased above about 35 mM; below 35 mM the R-H of the spherical micelles changes Little with ionic strength

Mixed micelles of cationic surfactants and sodium cholate in water

107-112Critical micelle concentrations (CMCs) of cationic surfactant (alkyltrimethylammonium bromides, CnTABr, where n = 10, 12, 14, 16 and 18), and a bile salt sodium cholate (NaC) were determined from surface tension, conductance and dye solubilization methods, while of their equimolar mixtures from surface tension and dye solubilization methods. The interaction parameter (β) obtained from analysis of data, using Rubingh’s theory showed strong interaction between NaC and cationic surfactant. Time-resolved fluorescence-quenching results revealed small-sized mixed spherical micelle with aggregation number much less than micelles of cationic surfactant