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Background: Dandruff is a pervasive chronic condition which negatively impacts quality of life. Effective treatment requires efficient delivery of scalp benefit agents that control commensal scalp Malassezia levels. Delivery of benefit agents from shampoos requires balancing many technical parameters to achieve the desired outcome without sacrificing secondary parameters, such as cosmetic attributes. Aim: To develop formulation technologies that increase the shampoo delivery efficiency of the scalp benefit agent piroctone olamine (PO). Increased delivery should result in increased anti‐dandruff efficacy. Methods: Micellar Stability and Association parameters were quantified via dynamic surface tension and nuclear magnetic resonance (NMR) diffusion parameters, respectively. PO delivery has been assessed in vivo both on the scalp surface and follicular infindibula using extraction procedures and analytical analysis. Clinical anti‐dandruff efficacy was assessed for an advanced delivery technology prototype in comparison to standard delivery technology. Results: Shampoo prototypes have been developed that increase the delivery efficiency of PO. Both surfactant and polymer coacervate‐based approaches have been developed. Decreased micellar stability results in weaker association between PO and micelles, resulting in more efficient PO retention on the scalp surface and delivery to the infundibula. Increased charge density of cationic polymers optimizes coacervation enabling improved PO delivery as well. Increased PO delivery has been shown clinically to result in higher anti‐dandruff efficacy as measured by both visible flakes and underlying biomarkers. Conclusion: Increased efficiency PO delivery shampoos have been developed by optimization of both surfactant and coacervate parameters. The increased deposition efficiency results in significantly more products with significantly greater anti‐dandruff efficacy. [ABSTRACT FROM AUTHOR]

• Dynamic micelles of 4-dodecylbenzenesulfonic acid (DBSA) at below < 75 mM. • Very stable micelles of DBSA at higher concentrations (>75 mM). • Efficiency of dynamic DBSA micelles in micellar catalysis in water. • Less activity of vesicles and stable micelles of DBSA in micellar catalysis. • Importance of molecular packing of DBSA at interface in micellar catalysis. The 4-dodecylbenzenesulfonic acid (DBSA), a Brønsted acid surfactant combined catalyst, forms micelles and vesicles in water. The dynamic DBSA micelles, which are present at lower concentrations (<75 mM), are more efficient in micellar catalysis in water. The dynamic micelles supply high flux of monomers to emulsify the water-insoluble/ non-polar reactant in water creating huge interface. The large intermolecular distance between DBSA at interface of emulsions provides appropriate microenvironment for the reaction (space to accommodate the molecules of reactant(s) and reaction intermediates, and accessible H+ ions). At higher concentrations (>75 mM), micelles become very stable, which have good solubilization capacity for the water-insoluble reactant. However, the stable micelles are less active in micellar catalysis due to the close molecular packing of DBSA strongly solubilizing the reactant(s) and reducing the accessibility of H+ ions due to extensive hydrogen bonding between –SO 3 H groups. [ABSTRACT FROM AUTHOR]

Abstract A specific condition directing the formation of silver nanoparticles (AgNPs) with narrow size-distribution in aqueous sodium dodecyl sulphate (SDS) solutions, using trisodium citrate (TSC) is investigated. The peculiar control in distribution of size for AgNPs in presence of 35 mM (~1 wt%) aqueous SDS solution as stabilizing agent is evident. Water penetration through packed PTFE powder and dynamic surface tension measurements demonstrate formation of stable aggregates at the given condition and accordingly reduced numbers of free SDS monomers diffusing to the growing AgNP interface. The smaller size of AgNPs was also confirmed by TEM images, which illustrates mixed morphologies for the nanoparticles in an aggregated state. The NMR experiments reveal strong hydrophobic interactions between the alkyl chains of SDS molecules adsorbed on AgNPs. These results also indicate that TSC is molecularly distributed in bulk phase without binding to the SDS micellar aggregates. A plausible molecular mechanism is proposed based on diffusion of Ag+ ions to the growing AgNP surface along with SDS monomers and submicellar aggregates, subsequently forming bigger size AgNPs. The narrow distribution of size for AgNP in presence of 35 mM SDS is arguably driven by the capping of stable SDS micelles or monomers around growing nuclei and restricted number of SDS monomers and submicellar aggregates responsible for supply of Ag+ at the growing AgNP nuclei. Graphical abstract Unlabelled Image Highlights • AgNPs with narrow distribution of size are synthesized at 35 mM SDS concentration in presence of 3.5 mM TSC. • Least water penetration in packed PTFE powder is noticed for mixtures containing 35 mM SDS concentration. • NMR data reveal increase in hydrophobic interactions between the alkyl chains of SDS molecules during AgNP formation. • Large population of free monomers and submicellar aggregates presumably drives the Ag+ ions to the growing AgNP surface. • TEM images confirm the formation of anisotropic AgNP morphologies in presence of 35 mM SDS as stabilizer. [ABSTRACT FROM AUTHOR]

An amphiphilic block copolymer of poly(ethylene oxide)- b-poly(( N-methacryloxy phthalimide)- co-(7-(4-vinyl-benzyloxyl)-4-methylcoumarin)) (PEO45- b-P(MAPI36- co-VBC4)) is designed to improve the micellar stability during the photo-triggered release of hydrophobic cargoes. Analysis of absorption and emission spectra, solution transmittance, dynamic light scattering, and transmission electron microscopy supports that polymer micelles of PEO45- b-P(MAPI36- co-VBC4) upon the combinational irradiation of 365 and 254 nm light can be solubilized through the photolysis of phthalimide esters and simultaneously crosslinked via the partially reversible photo-dimerization of coumarins. The photo-triggered release experiment shows that the leakage of doxorubicin molecules from crosslinked micelles can be predictably regulated by controlling the irradiation time of 365 and 254 nm light. [ABSTRACT FROM AUTHOR]

This study evaluated the properties of poly(ethylene oxide)-b-poly(n-butyl acrylate)-b-poly(acrylic acid) (PEO-PnBA-PAA) polymeric micelles as carriers for anti-inflammatory drugs (prednisolone and budesonide). The micelles comprising a hydrophobic PnBA core and a PEO/PAA corona showed average diameter less than 40 nm. The size of the drug-loaded micelles did not change during eight hours into media that mimic physiological fluids indicating high colloidal stability. The calculation of Flory–Huggins parameter showed greater compatibility between budesonide and micellar core suggesting its location in the micellar core, whereas prednisolone was located also into the interface layer. This observation correlated further with slower release of budesonide, especially in acid medium (pH = 1.2). The inclusion of budesonide into micelles showed significant protective effect against the cytotoxic damage induced by the co-cultivation of differentiated human EOL-1 and HT-29 cells. This study revealed the capacity of PEO-PnBA-PAA terpolymer as carrier of nanosized micelles suitable for oral delivery of anti-inflammatory drugs. [ABSTRACT FROM PUBLISHER]

The critical micelle concentrations (cmc) of mixed systems comprising an amphiphilic drug amitriptyline hydrochloride and counterion-coupled gemini surfactants 12-6-12, 14-6-14, or 16-6-16 [1,6-bis( N, N-alkyldimethylammonium) adipate] were determined using tensiometry. The results were analyzed in the light of different theoretical models from Rosen, Clint, Rubingh, and Motomura. The cmc values decrease with increasing mole fraction of surfactant ( α). The cmc values (cmc value at ideal mixing conditions) also decrease with α but remain above the experimental cmc values. This means that the mixed micelles form as a result of attractive interactions. These interactions are also seen in surface excess concentration (Γ) and minimum area per molecule ( A) data: Γ increases and A decreases. Both Rosen's and Rubingh's models indicate synergistic interactions (interaction parameter, β and β, values are negative). The β values are larger in magnitude than β for 14-6-14 and 16-6-16 systems, whereas the reverse is the case with 12-6-12 because the surfactant's short chain makes adjustment in the core difficult for both components. [ABSTRACT FROM AUTHOR]

Abstract: Novel casein (CAS)-based micelles loaded with the poorly soluble anti-cancer drug, flutamide (FLT), were successfully developed in a powdered form via spray-drying technique. Genipin (GNP) was used to crosslink CAS micelles as demonstrated by color variation of the micelles. Drug solubilization was enhanced by incorporation within the hydrophobic micellar core which was confirmed by solubility study and UV spectra. Spherical core–shell micelles were obtained with a particle size below 100nm and zeta potential around −30mV. At low drug loading, FLT was totally incorporated within micellar core as revealed by thermal analysis. However, at higher loading, excess non-incorporated drug at micelle surface caused a significant reduction in the surface charge density. Turbidity measurements demonstrated the high physical stability of micelles for 2weeks dependent on GNP-crosslinking degree. In a dry powdered form, the micelles were stable for 6months with no significant changes in drug content or particle size. A sustained drug release from CAS micelles up to 5days was observed. After i.v. administration into rats, CAS micelles exhibited a prolonged plasma circulation of FLT compared to drug solution. Furthermore, a more prolonged drug systemic circulation was observed for GNP-crosslinked micelles. Overall, this study reports the application of spray-dried natural protein-based micelles for i.v. delivery of hydrophobic anti-cancer drugs such as FLT. [Copyright &y& Elsevier]

Abstract: Mixed micelles formed by critical micelle concentration (Cmc) character''s diblock copolymer, and temperature-sensitive character''s diblock copolymer were studied for their capabilities in improving stability with and without drug. Experimental results showed that this type of mixed micellar systems possessed complementary effects in adjusting external temperature shift (storage vs. body temperature) and concentration change (dilution after intravenous injection). Therefore, they provided excellent stability as drug carriers. Further results obtained from physicochemical property and drug release kinetics studies demonstrated such systems could also be applied to physiological conditions, in compliance with varied pH environments. We concluded that the newly developed mixed micelles can serve as a potential injectable drug delivery system for anticancer drugs, such as doxorubicin and many others. [Copyright &y& Elsevier]

In this study, caseins micelles were internally cross-linked using the enzyme transglutaminase (TGase). The integrity of the micelles was examined on solubilization of micellar calcium phosphate (MCP) or on disruption of hydrophobic interactions and breakage of hydrogen bonds. The level of monomeric caseins, determined electrophoretically, decreased with increasing time of incubation with TGase at 30°C; after incubation for 24 h, no monomeric ß- or k-caseins were detected, whereas only a small level of monomeric αS1-casein remained, suggesting near complete intramicellar cross-linking. The ability of casein micelles to maintain structural integrity on disruption of hydrophobic interactions (using urea, sodium dodecyl sulfate, or beating in the presence of ethanol), solubilization of MCP (using the calcium-chelating agent trisodium citrate) or high-pressure treatment was estimated by measurement of the L*-value of milk; i.e., the amount of back-scattered light. The amount of light scattered by casein micelles in noncross-linked milk was reduced by >95% on complete disruption of hydrophobic interactions or complete solubilization of MCP; treatment of milk with TGase increased the stability of casein micelles against disruption by all methods studied and stability increased progressively with incubation time. After 24 h of cross-linking, reductions in the extent of light scattering were still apparent in the presence of high levels of dissociating agents, possibly through citrate-induced removal of MCP nanoclusters from the micelles, or urea- or sodium dodecyl sulfate-induced increases in solvent refractive index, which reduce the extent of light-scattering. [ABSTRACT FROM AUTHOR]

Abstract: The visible spectra of Safranine T (ST) in micellar solution of Brij 58, Tween 20 and Tween 40 and mixed micellar solution of Brij 58/Tween 20 and Brij 58/Tween 40 indicate formation of 1:1 charge transfer (CT) complex between acceptor ST and donor nonionic micelles and mixed micelles. The experimental CT transition energies are well correlated (through Mulliken''s equation) with the vertical ionization potential of the donors. The solvent parameters, i.e. the intramolecular charge transfer energy E T(30) have been determined from the Stokes spectral shift. Variations of ionization potential and micropolarity in the mixed micellar region have been investigated as a function of surfactant composition and the obtained results in mixed micellar medium has been compared to the normal micelles. The critical micelle concentration (CMC) values determined at various surfactant compositions are lower than the ideal values indicating a synergistic interaction. The interaction parameter (β) and micellar stability has been calculated using regular solution theory. [Copyright &y& Elsevier]