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The chemical composition of polysorbate 80 strongly influences the physicochemical properties and performance of many products. Consequently, a reliable characterization of polysorbate 80 is crucial for many applications. However, the exact composition of these chemical mixtures cannot be determined by colorimetry, hydrolysis, size-exclusion chromatography, nuclear magnetic resonance or mass spectrometry (MS). Meanwhile, due to the strong retention of higher esters on the reversed-phase (RP) column, the published high-performance liquid chromatography (HPLC) methods suffered from inadequate elution. In the present paper, an HPLC-evaporative light scattering detection (ELSD) and an HPLC-electrospray ionization (ESI)-MS method were developed and validated for the separation and identification of the chemical composition of polysorbate 80. A full separation of the entire composition was achieved in 45 min. In the HPLC-ESI-MS spectra, each class of the compound in polysorbate 80 was directly confirmed and identified by [M + NH(4)](+) and [M + 2NH(4)](2+) ions. The number of polyoxyethylene groups and their distribution within the molecule were determined, in addition to the dehydration and esterification degree of sorbitol. Analysis showed that polysorbate 80 contained different proportions of components (polyoxyethylene sorbitan, polyoxyethylene isosorbide, polyoxyethylene sorbitan monooleate-dioesters-trioleates-tetraoleates and polyoxyethylene isosorbide monoester-dioesters). It was concluded that HPLC-ESI-MS is a useful tool for establishing the compositional profile of polysorbate 80.

The effect of phospholipid formulation and choice of surfactant on skin permeation of selected hydrophilic drugs from elastic liposomes across human epidermal membrane has been studied. Sodium cholate and various concentrations of phosphatidylcholine were used for the preparation of liposomes namely hydrogenated phosphatidylcholine 90% (Phospholipon 90H), phosphatidylcholine 95% (Phospholipon 90G), phosphatidylcholine 78.6% (Phospholipon 80), and phosphatidylcholine 50% (Phosal PG). To investigate the effect of the surfactant, liposomes were prepared from 95% phosphatidylcholine (Phospholipon 90G) and various surfactants (sodium cholate, sodium deoxycholate, Span 20 (sorbitan monolaurate), Span 40 (sorbitan monopalmitate), Span 60 (sorbitan stearate) and Span 80 (sorbitan monooleate)). The vesicles were prepared by the conventional rotary evaporation technique. The film was hydrated with phosphate-buffered saline (10 mL) containing 9, 2 and 2.5 mg mL−1 of methotrexate, idoxuridine and aciclovir, respectively. All formulations contained 7% ethanol. Homogenously-sized liposomes were produced following extrusion through 100-nm polycarbonate filters using Lipex Extruder. Particle size was characterized by transmission electron microscopy. Vertical Franz diffusion cells were used for the study of drug delivery through human epidermal membrane. For the three drugs, the highest transcutaneous fluxes were from elastic liposomes containing 95% phosphatidylcholine. In general, a higher flux value was obtained for liposomes containing sodium cholate compared with sodium deoxycholate. For the liposomes containing sorbitan monoesters, there was no clearly defined trend between alkyl chain length and flux values. Overall, transcutaneous fluxes of liposomal preparations of hydrophilic drugs were comparable with those from saturated aqueous solutions (P > 0.05).

Oil-in-water (O/W) lipid emulsions are suitable drug carriers for lipophilic drugs; however, the effects of numbers or chains of oxyethylene units within a surfactant molecule such as polyoxyethylene sorbitan esters (PSs) on the biological fate of these lipid emulsions have not yet been clarified. In this study, a series of PSs and soybean oil (SO) were utilized to prepare menatetrenone-incorporated lipid emulsions (SO/PSs), and the biological fate of menatetrenone administered as SO/PSs was studied at a clinical injection volume (0.1 mL kg−1) in rats. The plasma concentration and organ uptake of menatetrenone administered as SO/20OE-PSs (PSs with 20 oxyethylene units) was similar to that of SO/egg-yolk phosphatides (SO/EYP). The plasma concentration of menatetrenone was extensively lower for SO/6OE-PSs (PSs with 6 oxyethylene units) and SO/20OE-3FA-PSs (PSs with 20 oxyethylene units and 3 fatty acid chains) than that for SO/EYP, and menatetrenone uptake by the liver and spleen was higher for SO/6OE-PSs and SO/20OE-3FA-PSs, respectively, than those for SO/EYP. Furthermore, menatetrenone uptake by the lungs was also increased for SO/6OE-PS and SO/20OE-3FA-PS with double bonds in the fatty acid moieties of the PSs. These findings suggested that shortening the oxyethylene units or decreasing the oxyethylene chain numbers of emulsifiers resulted in a rapid clearance of the lipid emulsions from the circulation by extensive uptake via the liver, spleen or lungs.

This study evaluated the potential of poly(iso-butyl cyanoacrylate) (PBCA) nanocapsules dispersed in a biocompatible microemulsion to facilitate the absorption of insulin following intragastric administration to diabetic rats. Insulin-loaded PBCA nanocapsules were prepared in-situ in a biocompatible water-in-oil microemulsion by interfacial polymerisation. The microemulsion consisted of a mixture of medium-chain mono-, di- and tri-glycerides as the oil component, polysorbate 80 and sorbitan mono-oleate as surfactants and an aqueous solution of insulin. Resulting nanocapsules were approximately 200 nm in diameter and demonstrated a high efficiency of insulin entrapment (> 80%). In-vitro release studies showed that PBCA nanocapsules could suppress insulin release in acidic media and that release at near neutral conditions could be manipulated by varying the amount of monomer used for polymerisation. Subcutaneous administration of insulin-loaded nanocapsules to diabetic rats demonstrated that the bioactivity of insulin was largely retained following this method of preparing peptide-loaded nanocapsules and that the pharmacodynamic response was dependent on the amount of monomer used for polymerisation. The intragastric administration of insulin-loaded nanocapsules dispersed in the biocompatible microemulsion resulted in a significantly greater reduction in blood glucose levels of diabetic rats than an aqueous insulin solution or insulin formulated in the same microemulsion. This study demonstrates that the formulation of peptides within PBCA nanocapsules that are administered dispersed in a microemulsion can facilitate the oral absorption of encapsulated peptide. Such a system can be prepared in-situ by the interfacial polymerisation of a water-in-oil biocompatible microemulsion.

Fatty acid monoesters of polyxyethylene sorbitan (Tween 40, Tween 60, Tween 80) were covalently linked with Remazol brilliant blue R. As a result, new water-soluble, dye-labelled fatty acid derivatives were obtained, suitable for the preliminary detection of lipolytic microorganisms in agar media. A simple and direct, highly sensitive and continuous plate-clearing assay was developed, based on the formatio of clearing-diffusion zones around substrate-degrading colonies.

The mechanism of the separating effect of fatty acid ester (FAE) has been studied in frozen starch noodles (FSN). This was examined by FAE adsorption on the starch surface and by FAE effects on viscosity, adhesive force, syneresis and iodine-affinity of starch paste. The present and previous results indicate that separating effect of FAE has a close relationship to the interaction of FAE with starch. The following factors are at least important in the separating effect of FAE; (a) adsorption of FAE on starch surface and (b) the subsequent action of FAE to reduce the viscosity and adhesive force of starch paste. The reason for FAE, especially sorbitan sterate or glycerin sterate, being effective in the separating action of FSN probably lies in the FAE ability to satisfy the above requirements.

The kinetics of the hydrolysis of the oleate ester of polyoxyethylene (20) sorbitan (Tween 80) in aqueous buffers were studied at an initial concentration of 0ṁ020% (w/v) and over the pH range of 1ṁ10 to 10ṁ28. The hydrolysis appears to be specific acid-catalysed at pH values below 3 and specific base-catalysed at pH values greater than 7ṁ6. The pseudo first-order rate constants for hydrogen and hydroxyl ion catalysis were determined, and the temperature and ionic strength dependence of the acid-catalysed reaction was studied. Both the initial, acid- and base-catalysed hydrolysis of Tween 80 exhibited an unusual initial, micellar surfactant concentration-rate dependence, opposite to that previously reported for the hydrolysis of anionic surfactants of the n-alkyl sulphate-type. Specifically, as the initial concentration of Tween 80 was increased above its reported critical micellar concentration, there was a progressive, marked decrease in the rate of the reaction, with the rate eventually reaching a plateau value between 0ṁ100 and 1ṁ00% (w/v). It is suggested that this behaviour is due to alterations in the micellar state of the surfactant as its concentration is increased. The influence of the chemical structure of the Tween surfactant on the acid-catalysed hydrolysis reaction at 80° was also examined using the oléate (Tween 80), stéarate (Tween 60), and palmitate (Tween 40) esters of polyoxyethylene (20) sorbitan.

A method is described for gas chromatographic (GC) determination of sorbitan fatty acid esters in confectionery products as sorbitan monostearate. A sample is homogenized with chloroform, filtered, dried, and saponified with 0.1N NaOH in ethanol 1 h at 80°C. The saponification mixture is acidified, washed with hexane, and dried. Isosorbide, 1,4-sorbitan, and D-sorbitol are each derivatized at 70°C with pyridine, hexamethyldisilazane, and trimethylchlorosilane. GC separation of the polyols as TMS (trimethylsilyl) derivatives was performed on a 2% Dexsil 300 column temperature-programmed from 120 to 250°C at 107 min. The sorbitan monostearate content of the sample was calculated from the polyols, using the appropriate conversion factor. The procedure was applied to ice creams, cakes, and other confectionery products. Average recoveries from samples spiked with 1.0% Span 60 (sorbitan monostearate) were 91-96% for isosorbide, 83-99% for 1,4-sorbitan, and 82-98% for D-sorbitol. The detection limit was approximately 0.01%.

The effectiveness of various surfactants in the control of larvae of the bollworm, Heliothis zea (Boddie), tobacco budworm, H. virescens (F), and pink bollworm, Pectinophora gossypiella (Saunders), was evaluated. When cotton bolls containing diapausing pink bollworm larvae were dipped in Triton® X-150 (ethoxylated alkylphenol blends with organic sulfonates) or Triton® X-100 and X-155 (ethoxy1ated alkylphenols) at 2 or 5%, moth emergence was reduced by 89% or more compared with emergence from untreated bolls, and Tween® 65 and 85 were more effective than Tween® 60, 61, 80, or 40 (allethoxylated sorbitan esters) at 2 or 5%. In laboratory tests with foliar sprays at 2.5 kg per hectare, ethoxylated tridecyl alcohol containing mole ratios of 15:1 of ethylene oxide to alcohol killed more bollworms than the 3:I mole ratio. Retzolate 58 (ammonium salts of ethoxylated alcohol sulfates) at 4.5 kg per hectare alone killed 40% or more bollworm and tobacco budworm larvae. Also when Retzloff DRS 22 or DRB 203 (polymeric phenolic resins) at 2.2 kg per hectare were added to carbaryl at 2.2 kg per hectare and used as a foliar spray on both dry and wet leaf surfaces, they killed more bollworm larvae than the insecticides alone. In field-cage tests, Rerzamide LAX and Retzamide COA (alkanolamides) and Retzloff DTG 62 (ethoxylated polyols) at 2.2 kg per hectare, each combined with DDT at 2.2 kg per hectare or carbaryl at 2.2 kg per hectare, killed more tobacco budworms than the insecticides alone.