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High-Performance Liquid Chromatography
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
Joel J. Kirschbaum, Adorjan Aszalos
Nalidixic acid is used intravenously to treat systemic infections, especially those of the urinary tract. To determine nalidixic acid and its active metabolite, hydroxynalidixic acid, in plasma, an octadecylsilane column was used with a mobile phase of water-methanol-cetrimonium bromide (cetrimide) (50:50:0.12) flowing at 1.5 ml/min into a detector set to 313 nm [455]. The limit of detection of 1 μg/ml is well below the therapeutic range of 20—50 μg/ml. Recoveries are approximately 90%. Contents in plasma and urine were assayed using an amino-cyano column and a mobile phase of methanol-0.1 M citrate buffer, pH 3 (95:15 [sic]), flowing at 1.6 ml/min. Detection at 254 nm gave limits of detection of 0.08 μg/ml plasma and 0.42 μg/ml urine [456].
Chemical Modulation of Topical and Transdermal Permeation
Published in Marc B. Brown, Adrian C. Williams, The Art and Science of Dermal Formulation Development, 2019
Marc B. Brown, Adrian C. Williams
Surfactants can be further classified according to the nature of the hydrophilic moiety; anionic surfactants have a negatively charged head group, such as from sulphate and phosphate moieties: for example, sodium lauryl sulphate (SLS). Cationic surfactants carry a positively charged head group that could be from a pH-dependent amine or from permanently charged quaternary ammonium salts, such as with cetrimonium bromide or benzalkonium chloride. Zwitterionic (amphoteric) surfactants have both cationic and anionic moieties attached to the same molecule, such as dodecyl betaine. Non-ionic surfactants are very commonly selected for use in transdermal and topical formulations and contain covalently bonded oxygen-containing hydrophilic head groups. There are many non-ionic surfactants available, including: poloxamers (triblock copolymers, known by their trade names Synperonics, Pluronics, and Kolliphor), sorbitan esters (also known as Spans), and polysorbates (known commonly as Tweens).
Proteins in Cosmetics
Published in E. Desmond Goddard, James V. Gruber, Principles of Polymer Science and Technology in Cosmetics and Personal Care, 1999
E. Desmond Goddard, James V. Gruber
Finally, proteins are reported to be potential inhibitors of numerous preservatives commonly used in cosmetics (130). The mechanisms involved are various and not fully understood: the reactivity of amino groups and electrostatic interactions are both possible. Also, protein materials are generally good substrates for microbial growth and partial inactivation of the preservative system may be the result of the higher consumption of biocides needed to face an increased microbial proliferation. Formaldehyde intentionally used or liberated by relevant donor biocides is easily consumed by condensation with free amino groups of peptides. Protein hydrolysates, having a high percentage of reactive amines, are stronger inactivation agents than larger proteins, while large polypeptides may lose solubility by masking the few amino groups present into nonionizable derivatives. Quaternary preservatives such as benzalkonium chloride and cetrimonium bromide may be inactivated by electrostatic interaction with anionic peptides, and potential inhibition is also reported for phenols, phenoxyethanol, and isothiazolinones.
Design of minocycline-containing starch nanocapsules for topical delivery
Published in Journal of Microencapsulation, 2018
J. M. Marto, L. F. Gouveia, L. M. D. Gonçalves, H. M. Ribeiro, A. J. Almeida
Minocycline hydrochloride (MH), alcohol, pre-gelatinized starch (Starch 1500), wheat starch and corn starch were obtained from Laboratórios Atral S.A. (Portugal). Ethoxydiglycol (Transcutol® CG) and caprylocaproyl macrogol-8 glycerides (caprylocaproyl) (Labrasol®) were a gift from Gattefossé (Lyon, France). Caprylic/capric triglycerides (Miglyol® 812) were a gift from Sasol Olefins & Surfactants GmbH (Hamburg, Germany). Phenoxyethyl caprylate (Tegosoft® XC), PEG-7 glyceryl cocoate (Tegosoft® GC), ethylhexyl stearate (Tegosoft® OS), diethylhexyl carbonate (Tegosoft® DEC), isopropyl myristate (Tegosoft® M) and decyl oleate (Tegosoft® DO) were a kind gift from Evonik Industries AG (Essem, Germany). Pregelatinized modified starch (Instant Pure-Cote® B793) was a kind gift from Grain Processing Corporation (Washington, USA). Modified starches (Pure-Gel® B990, Pure-Gel® B994, Pure-Cote® B790 and Instant Pure-Cote® B793) were a kind gift from Grain Processing Corporation’s (USA). Polyethylene glycol (Lutrol® E 400) was a gift from BASF (Rheim, Germany). Cetrimonium bromide (cetrimide) was a gift from DS Produtos Químicos (São Domingos de Rana, Portugal). Polysorbate 80 (Tween® 80) was obtained from Merck (Kenilworth, USA). Ethanol was obtained from Carlo Erba Reagents (Cornaredo, Italy). Purified water was obtained by reverse osmosis and electrodeionization (Millipore, Elix 3, Oeiras, Portugal) being afterwards filtered (pore 0.22 µm).
Summary of numerical analyses for therapeutic uses of laser-activated gold nanoparticles
Published in International Journal of Hyperthermia, 2018
Plasmonic photo-thermal therapy is a promising approach in the treatment of hyperthermia. Gold nanoparticles possess unique properties that make them suitable therapeutic agents in tumour tissue destruction. Furthermore, their properties are easily tailored to fit the particular purposes by changing their shapes, or by imposing surface modifications. However, to become a clinical praxis standard, more investigations are still needed. First, toxicity was reported in some studies, especially in earlier research studies mainly owing to the use of cetrimonium bromide (CTAB) in the preparation. Second, the effective target binding on the tumour site has been shown to be of great importance. An intensive research and rapid development is still in progress investigating both tasks.
Fabrication, optimisation and evaluation of cisplatin-loaded nanostructured carriers for improved urothelium permeability for intravesical administration
Published in Journal of Microencapsulation, 2021
Ting-Yu Chen, Yu-Yao Tai, Li-Ching Chang, Pao-Chu Wu
In this study, capryol 90, cetrimonium bromide, and mixture of 1,5-pentanediol and transcutol were used as oil phase, surfactant, and cosurfactant, respectively, to prepare the cisplatin-loaded microemulsion. Capryol 90 is an oil which has been investigated extensively for the preparation and optimisation of microemulsions of various poorly soluble drugs both in vitro as well as in vivo (Shakeel et al. 2013). Cetrimonium bromide is a quaternary ammonium salt, and has frequently been used for a variety of purposes such as antistatic agent, cleansing agent, emulsifying agent, and suspending agent in cosmetic products at concentrations of up to 10% (w/v) (Becker et al. 2012). Cosurfactant can reduce the amount of surfactant needed to formulate microemulsion, due to it softening up the interface surfactant film between oil/water phases and increases equilibration rate and formation of low-viscosity microemulsions; however, while alcohol is used as cosurfactant to decrease solubility of oil and water in microemulsions, the value of interfacial tension would increase with certain surfactants. This disadvantage might be countered by using mixtures of cosurfactant (Negin et al. 2017). 1,5-Pentanediol and transcutol are common cosurfactants and they also possess penetration enhancement effect (Alany et al. 2000, Osborne et al.2018), thus, the mixture of 1,5-pentanediol and transcutol was used as cosurfactant. Methylcellulose is a hydrophilic cellulose and is used to increase the viscosity of microemulsions. From our preliminary study, the amount of surfactant needs to be larger than 2% (w/w), and the microemulsion formulation is easy to form, so the amount of cetrimonium bromide was fixed at 2% (w/w). In this study, the effect of additional amount of oil phase and cosurfactant on permeability was investigated. A total of 12 model formulations were prepared as per the factorial experimental design, except for formulation 11 with a high-amount oil phase and a low-amount cosurfactant presence so cannot form formulation. The size of the vesicles was found to vary between 235.8 and 309.3 nm, which were in nanoscale. The PDI of model formulations ranged from 0.15 to 0.21, indicating the mono-dispersed microemulsions were obtained (Liu et al. 2011). The viscosity of formulations ranged from 550.8 to 861.7 cps. The zeta potential ranged from 52.70 to 88.8. It was found that the zeta potential increased with the increase of X1. In general, successful passive transdermal delivery is restricted to particle size being less than 500 nm (Kohli et al.2004), indicated that the designed carrier had potential to improve the permeation capability of drug. The image of the cisplatin-loaded microemulsion is shown in Figure 1.