Sonication and heat-mediated synthesis, characterization and larvicidal activity of sericin-based silver nanoparticles against dengue vector (Aedes aegypti).

Fabrication, characterization and evaluation of the larvicidal potential of novel silk protein (sericin)-based silver nanoparticles (Se-AgNPs) were the prime motives of the designed study. Furthermore, investigation of the sericin as natural reducing or stabilizing agent was another objective behind this study. Se-AgNPs were synthesized using sonication and heat. Fabricated Se-AgNPs were characterized using particle size analyzer, UV spectrophotometry, FTIR and SEM which confirmed the fabrication of the Se-AgNPs. Size of sonication-mediated Se-AgNPs was smaller (7.49 nm) than heat-assisted Se-AgNPs (53.6 nm). Being smallest in size, sonication-assisted Se-AgNPs revealed the significantly highest (F4,10 = 39.20, p = .00) larvicidal activity against fourth instar lab and field larvae (F4,10 = 1864, p = .00) of dengue vector (Aedes aegypti) followed by heat-assisted Se-AgNPs and positive control (temephos). Non-significant larvicidal activity was showed by silver (without sericin) which made the temperature stability of silver, debatable. Furthermore, findings of biochemical assays (glutathione-S transferase, esterase, and acetylcholinesterase) showed the levels of resistance in field strain larvae. Aforementioned findings of the study suggests the sonication as the best method for synthesis of Se-AgNPs while the larvicidal activity is inversely proportional to the size of Se-AgNPs, i.e., smallest the size, highest the larvicidal activity. Conclusively, status of the sericin as a natural reducing/stabilizing agent has been endorsed by the findings of this study. RESEARCH HIGHLIGHTS: Incorporation of biocompatible and inexpensive sericin as a capping/reducing agent for synthesis of Se-AgNPs. A novel sonication method was used for the fabrication of Se-AgNPs which were thoroughly characterized by particle size analyzer, UV-visible spectrophotometry, SEM and FTIR. Analysis of enzymatic (GSTs, ESTs) levels in field and lab strains of Aedes aegypti larvae for evaluation of insecticides resistance.

Improving the in vitro and in vivo bioavailability of pterostilbene using Yesso scallop gonad protein isolates-epigallocatechin gallate (EGCG) conjugate-based emulsions: effects of carrier oil.

This study investigated the influence of carrier oils on the in vitro and in vivo bioavailability of PTE encapsulated in scallop gonad protein isolates (SGPIs)-epigallocatechin gallate (EGCG) conjugate stabilized emulsions. The SGPIs-EGCG stabilized emulsions were subjected to an in vitro simulated digestion, and the resulting corn oil and MCT micelles were used to evaluate the PTE transportation using the Caco-2 cell model. Both emulsions remarkably improved the bioaccessibility of PTE in the micelle phase. Nevertheless, corn oil emulsions increased trans-enterocyte transportation of PTE more efficiently than MCT emulsions. Furthermore, the maximum plasma concentrations of PTE and its metabolites in mice fed with PTE emulsions were prominently higher than those in mice fed with PTE solution, while the in vivo metabolic patterns of PTE in different oil-stabilized emulsions were different. Therefore, SGPIs-EGCG stabilized emulsions could enhance the bioavailability of PTE through controlled release, in which corn oil is more suitable than MCT.

Impact of excipient emulsions made from different types of oils on the bioavailability and metabolism of curcumin in gastrointestinal tract.

Low bioavailability currently limits the potential of curcumin as a health-promoting dietary compound. This study therefore explored the potential of excipient emulsions to improve curcumin bioavailability. Oil-in-water excipient emulsions were prepared using different types of oils: corn oil, olive oil, and medium chain triglycerides (MCT). The excipient emulsions increased the transportation rate of curcumin across the Caco-2 cell monolayer and showed ability to protect curcumin from metabolism in the enterocytes, with the olive oil-based systems exhibiting the highest efficacy. In addition, most of curcumin metabolites were present as hexahydro-curcumin (HHC) and its conjugates. Our results show that excipient emulsions can improve curcumin bioavailability by increasing its trans-enterocyte absorption and reducing cellular metabolism. Moreover, they show that these effects depend on the type of oil used to produce them. These findings have important implications for the rational design of lipid-based delivery systems to enhance the bioavailability of hydrophobic nutraceuticals like curcumin.

Evaluation of the Physico-mechanical Properties and Electrostatic Charging Behavior of Different Capsule Types for Inhalation Under Distinct Environmental Conditions.

Capsule-based dry powder inhaler (DPI) products can be influenced by a multitude of interacting factors, including electrostatic charging. Tribo-charging is a process of charge transfer impacted by various factors, i.e., material surface characteristics, mechanical properties, processing parameters and environmental conditions. Consequently, this work aimed to assess how the charging behavior of capsules intended for inhalation might be influenced by environmental conditions. Capsules having different chemical compositions (gelatin and hydroxypropyl methylcellulose (HPMC)) and distinct inherent characteristics from manufacturing (thermally and cold-gelled) were exposed to various environmental conditions (11%, 22% and 51% RH). Their resulting properties were characterized and tribo-charging behavior was measured against stainless steel and PVC. It was observed that all capsule materials tended to charge to a higher extent when in contact with PVC. The tribo-charging of the thermally gelled HPMC capsules (Vcaps® Plus) was more similar to the gelatin capsules (Quali-G™-I) than to their HPMC cold-gelled counterparts (Quali-V®-I). The sorption of water by the capsules at different relative humidities notably impacted their properties and tribo-charging behavior. Different interactions between the tested materials and water molecules were identified and are proposed to be the driver of distinct charging behaviors. Finally, we showed that depending on the capsule types, distinct environmental conditions are necessary to mitigate charging and assure optimal behavior of the capsules.

Interactions of Oral Molecular Excipients with Breast Cancer Resistance Protein, BCRP.

Mechanistic-understanding-based selection of excipients may improve formulation development strategies for generic drug products and potentially accelerate their approval. Our study aimed at investigating the effects of molecular excipients present in orally administered FDA-approved drug products on the intestinal efflux transporter, BCRP (ABCG2), which plays a critical role in drug absorption with potential implications on drug safety and efficacy. We determined the interactions of 136 oral molecular excipients with BCRP in isolated membrane vesicles and identified 26 excipients as BCRP inhibitors with IC50 values less than 5 µM using 3H-cholecystokinin octapeptide (3H-CCK8). These BCRP inhibitors belonged to three functional categories of excipients: dyes, surfactants, and flavoring agents. Compared with noninhibitors, BCRP inhibitors had significantly higher molecular weights and SLogP values. The inhibitory effects of excipients identified in membrane vesicles were also evaluated in BCRP-overexpressing HEK293 cells at similar concentrations. Only 1 of the 26 inhibitors of BCRP identified in vesicles inhibited BCRP-mediated 3H-oxypurinol uptake by more than 50%, consistent with the notion that BCRP inhibition depends on transmembrane or intracellular availability of the inhibitors. Collectively, the results of this study provide new information on excipient selection during the development of drug products with active pharmaceutical ingredients that are BCRP substrates.

Improvement of carotenoid bioaccessibility from spinach by co-ingesting with excipient nanoemulsions: impact of the oil phase composition.

Many of the carotenoids found naturally in fruits and vegetables are beneficial to human health, but they often have low oral bioavailability because of their high hydrophobicity. In this study, the effects of varying the composition of the oil phase of excipient nanoemulsions on carotenoid bioaccessibility from spinach were investigated using a simulated gastrointestinal tract. Nanoemulsions containing different ratios of medium chain triglycerides (MCT) and long chain triglycerides (LCT) were prepared: (i) mixing MCT and LCT oils before homogenization and (ii) mixing MCT droplets with LCT droplets after homogenization. The release of carotenoids from spinach and their solubilization within the mixed micelles formed after lipid digestion depended strongly on the oil phase composition. As expected, carotenoid bioaccessibility was always higher in the presence of excipient nanoemulsions than in their absence. The total free fatty acids released in the small intestine increased as the MCT/LCT ratio increased, which can be attributed to the faster release of shorter chain fatty acids from the oil droplet surfaces during lipid digestion. As the MCT ratio increased, lutein bioaccessibility increased but ß-carotene bioaccessibility decreased. This difference was attributed to the ability of the formed mixed micelles to accommodate the two different kinds of carotenoids in their hydrophobic domains. Interestingly, carotenoid bioaccessibility was significantly lower (P < 0.05) when the oil droplets were mixed after homogenization than when the oils were mixed before homogenization. These results have important implications for the design of excipient foods to improve the bioavailability of hydrophobic nutraceuticals in fruits and vegetables.

Impact of plant extract on the gastrointestinal fate of nutraceutical-loaded nanoemulsions: phytic acid inhibits lipid digestion but enhances curcumin bioaccessibility.

The impact of phytic acid on lipid digestion and curcumin bioaccessibility in oil-in-water nanoemulsions was investigated using a simulated gastrointestinal tract (GIT). The size, charge, and structural organization of the colloidal particles in the system were measured as the curcumin-loaded emulsions (7 mg curcumin per g lipid) were passed through simulated mouth (pH 6.8, 2 min), stomach (pH 2.5, 2 hours), and small intestine (pH 7.0, 2 hours) stages. After the small intestine stage, the level of free fatty acids (FFAs) generated and the bioaccessibility of curcumin were measured. The total amount of FFAs released significantly decreased with increasing phytic acid level, from 105.7 ± 5.9% (control) to 78.4 ± 6.4% (0.5% phytic acid). Conversely, curcumin bioaccessibility significantly increased from 39.4 ± 3.5% (control) to 74.7 ± 2.6% (0.5% phytic acid). The inverse relationship between lipolysis and curcumin bioaccessibility was ascribed to the impact of phytic acid on droplet flocculation and the level of free calcium ions present, which affected the production of mixed micelles capable of solubilizing the nutraceutical. The knowledge obtained here might prove beneficial for the employment of phytic acid as a multifunctional ingredient that inhibits lipid digestion while boosting nutraceutical bioavailability.

Penetration study of oils and its formulations into the human hair using confocal microscopy.

BACKGROUND: Laser scanning confocal microscopy (LSCM) is a nondestructive method for observing the samples in three dimensions as well in their natural environment. Therefore, it is well suited for studying human hair. This investigation is focused on evaluating the comparative penetration ability of vegetable vs mineral oils and their formulations with excipient, in human hair. AIMS: Laser scanning confocal microscopy was employed to assess thin cross sections of human hair, treated with oils and their formulations, to comprehend their penetration capability and pattern. METHODS: Hair incubated with individual oils or their formulations were labeled with the fluorescent dye was cross-sectioned into thin fragments and visualized under the LSCM. RESULTS: The mineral oil demonstrated better penetration through the hair than the vegetable oils. Combination of these oils with excipient, in an appropriate ratio, had a substantial influence on oil penetration in terms of the depth of penetration. CONCLUSIONS: Our investigation proved the suitability of fluorescent-based imaging for studying the penetration of oils across human hair. This method can be employed as a potential analytical tool to study the penetration of various hair-care formulations and/or their additives, to estimate their effects on human hair.

Vitamins in cell culture media: Stability and stabilization strategies.

Nowadays, chemically defined cell culture media (CCM) have replaced serum- and hydrolysate-based media that rely on complex ingredients, such as yeast extracts or peptones. Benefits include a significantly lower lot-to-lot variability, more efficient manufacturing by reduction to essential components, and the ability to exclude components that may negatively influence growth, viability, or productivity. Even though current chemically defined CCMs provide an excellent basis for various mammalian biotechnological processes, vitamin instabilities are known to be a key factor contributing to the variabilities still present in liquid CCM as well as to short storage times. In this review, the chemical degradation pathways and products for the most relevant vitamins for CCM will be discussed, with a focus on the effects of light, oxygen, heat, and other CCM compounds. Different approaches to stabilize vitamins in solution, such as replacement with analogs, encapsulation, or the addition of stabilizing compounds will also be reviewed. While these vitamins and vitamin stabilization approaches are presented here as particular for CCM, the application of these concepts can also be considered relevant for pharmaceutical, medical, and food supplement purposes. More precise knowledge regarding vitamin instabilities will contribute to stabilize future formulations and thus decrease residual lot-to-lot variability.

Optimal Selection of Incoming Materials from the Inventory for Achieving the Target Drug Release Profile of High Drug Load Sustained-Release Matrix Tablet.

In the pharmaceutical process, raw material (including APIs and excipients) variability can be delivered to the final product, and lead to batch-to-batch and lot-to-lot variances in its quality, finally impacting the efficacy of the drug. In this paper, the Panax notoginseng saponins (PNS) sustained-release matrix tablet was taken as the model formulation. Hydroxypropyl methylcellulose with the viscosity of 4000 mPa·s (HPMCK4M) from different vendors and batches were collected and their physical properties were characterized by the SeDeM methodology. The in-vitro dissolution profiles of active pharmaceutical ingredients (APIs) from matrix tablets made up of different batches HPMC K4M displayed significant variations. Multi-block partial least squares (MB-PLS) modeling results further demonstrated that physical properties of excipients played dominant roles in the drug release. In order to achieve the target drug release profile with respect to those far from the criteria, the optimal selection method of incoming materials from the available was established and validated. This study provided novel insights into the control of the input variability of the process and amplified the application of the SeDeM expert system, emphasizing the importance of the physical information of the raw materials in the drug manufacturing process.

In Vivo Evaluation of Taste-Masked Fast-Disintegrating Sublingual Tablets of Epinephrine Microcrystals.

In community settings, IM injection of 0.3 mg epinephrine (Epi) using an auto-injector is the drug of choice for treatment of anaphylaxis. Previously, a taste-masking (TM) formulation of fast-disintegrating sublingual tablets (FDSTs) was developed in our lab. Also, Epi was micronized (Epi-MC) successfully and reduced the previously achieved bioequivalent sublingual Epi dose to 0.3 mg IM injection by half using non-taste-masked fast-disintegrating sublingual tablets (TM-FDSTs). Our objective for this study was to evaluate the sublingual absorption of Epi-MC using TM-FDST. These sublingual Epi tablets have potential for out-of-hospital treatment of anaphylaxis and are suitable for human studies. TM-FDSTs containing Epi-MC were manufactured by direct compression. The rate and extent of Epi absorption from our developed 20 mg Epi-MC-TM-FDSTs (n = 5) were evaluated in rabbits and compared to the previous result from 20 mg Epi-MC in non-TM-FDSTs and EpiPen® auto-injector. Blood samples were collected over 1 h, and Epi concentrations were measured using HPLC with electrochemical detection. Mean ± SEM AUC0-1 h and Cmax from 20 mg Epi-MC-TM-FDSTs (733 ± 78 ng/ml/min and 30 ± 8 ng/ml) and 20 mg Epi-MC-non-TM-FDSTs (942 ± 109 ng/ml/min and 38 ± 4 ng/ml) were not significantly different (p > 0.05) from each other or from EpiPen® (592 ± 50 ng/ml/min and 28 ± 3 ng/ml) but were significantly higher (p < 0.05) than endogenous Epi after placebo FDSTs (220 ± 32 ng/ml/min and 8 ± 1 ng/ml). Mean ± SD Tmax was not significantly different (p > 0.05) among all formulations. Epi-MC-TM-FDSTs formulation improved Epi absorption twofold and reduced the required bioequivalent dose by 50%, similar to results obtained using non-TM-FDSTs. The incorporation of TM excipients did not interfere with the absorption of Epi-MC.

Impact of Delivery System Type on Curcumin Bioaccessibility: Comparison of Curcumin-Loaded Nanoemulsions with Commercial Curcumin Supplements.

In this study, nanoemulsion-based delivery systems fabricated using three different methods were compared with three commercially available curcumin supplements. Powdered curcumin was dispersed into the oil-in-water nanoemulsions using three methods: the conventional oil-loading method, the heat-driven method, and the pH-driven method. The conventional method involved dissolving powdered curcumin in the oil phase (60 °C, 2 h) and then forming a nanoemulsion. The heat-driven method involved forming a nanoemulsion and then adding powdered curcumin and incubating at an elevated temperature (100 °C, 15 min). The pH-driven method involved dissolving curcumin in an alkaline solution (pH 12.5) and then adding this solution to an acidified nanoemulsion (pH 6.0). The three commercial curcumin products were capsules or tablets purchased from an online supplier: Nature Made, Full Spectrum, and CurcuWin. Initially, the encapsulation efficiency of the curcumin in the three nanoemulsions was determined and decreased in the following order: pH-driven (93%) > heat-driven (76%) > conventional (56%) method. The different curcumin formulations were then subjected to a simulated gastrointestinal tract (GIT) model consisting of mouth, stomach, and small intestine phases. All three nanoemulsions had fairly similar curcumin bioaccessibility values (74-79%) but the absolute amount of curcumin in the mixed micelle phase was highest for the pH-driven method. A comparison of these nanoemulsions and commercial products indicated that the curcumin concentration in the mixed micelles decreased in the following order: CurcuWin ≈ pH-driven method > heat-driven method > conventional method ≫ Full spectrum > Nature Made. This study provides valuable information about the impact of the delivery system type on curcumin bioavailability. It suggests that encapsulating curcumin within small lipid particles may be advantageous for improving its absorption form the GIT.

Effects of Various Pharmaceutical Excipients on the Intestinal Transport and Absorption of Sulfasalazine, a Typical Substrate of Breast Cancer Resistance Protein Transporter.

Breast cancer resistance protein (BCRP) transporter is an efflux transporter that utilizes energy from adenosine triphosphate hydrolysis to push its substrates, regardless of the concentration gradient. Its presence on the apical membrane of the intestinal mucosa is a major obstacle for the intestinal absorption of its substrates. In this study, we examined the effects of various pharmaceutical excipients on the intestinal transport and absorption of sulfasalazine, a BCRP substrate. Four excipients, including 0.05% and 0.075% BL-9EX, 0.01% and 0.05% Brij 97, 0.075% Labrasol, and 0.05% and 0.1% Tween 20 decreased the secretory transport of sulfasalazine in an in vitro diffusion chamber. Further investigation in an in situ closed loop experiment in rats showed that 0.05% and 0.1% BL-9EX and 0.1% Brij 97 effectively enhanced the intestinal absorption of sulfasalazine while maintaining minimal toxicity to the intestinal mucosa. However, 0.1% Brij 97 also increased the intestinal absorption of 5(6)-carboxyfluorescein, a paracellular marker compound. These findings suggest that BL-9EX might effectively inhibit the BCRP-mediated efflux of sulfasalazine in vivo, indicating that BL-9EX could improve the intestinal absorption of sulfasalazine and other BCRP substrates.

Pluronic-Based Mixed Polymeric Micelles Enhance the Therapeutic Potential of Curcumin.

Curcumin is a naturally occurring constituent of turmeric that is a good substitute for synthetic medicines for the treatment of different diseases, due to its comparatively safer profile. However, there are certain shortcomings that limit its use as an ideal therapeutic agent. In order to overcome these drawbacks, we prepared novel curcumin-loaded mixed polymeric micelles using different biocompatible polymers by the thin-film hydration method. We investigated the critical micelle concentration and temperature, drug loading and encapsulation efficiency, and minimum inhibitory concentration by spectrophotometry. Surface morphology, stability, particle size, drug-polymer interaction, and physical state of the prepared formulations were investigated using scanning electron microscopy, zeta potential, particle size analyzer, Fourier-transform infrared spectroscopy, and X-ray diffraction, respectively. The drug loading and entrapment efficiency were significantly increased (P < 0.01) when curcumin was encapsulated with pluronic-based mixed polymeric micelles as compared to that of pluronic-based micelles alone. In vitro studies exhibited that pluronic-based mixed polymeric micelles significantly increased anticancer (P < 0.01), antimicrobial (P < 0.001), antioxidant (P < 0.001), and α-amylase inhibitory (P < 0.001) activities when compared to pure curcumin and/or pluronic-based micelles alone. These findings suggest that the formation of mixed polymeric micelles increases the stability and solubility of curcumin.

Correlating in Vitro Solubilization and Supersaturation Profiles with in Vivo Exposure for Lipid Based Formulations of the CETP Inhibitor CP-532,623.

Lipid based formulations (LBFs) are a promising formulation strategy for many poorly water-soluble drugs and have been shown previously to enhance the oral exposure of CP-532,623, an oral cholesteryl ester transfer protein inhibitor. In the current study, an in vitro lipid digestion model was used to probe the relationship between drug solubilization and supersaturation on in vitro dispersion and digestion of LBF containing long chain (LC) lipids and drug absorption in vivo. After in vitro digestion of LBF based on LC lipids, the proportion of CP-532,623 maintained in the solubilized state in the aqueous phase of the digest was highest in formulations containing Kolliphor RH 40, and in most cases outperformed equivalent formulations based on MC lipids. Subsequent administration of the LC-LBFs to beagle dogs resulted in reasonable correlation between concentrations of CP-532,623 measured in the aqueous phase of the in vitro digest after 30 min digestion and in vivo exposure (AUC); however, the LC-LBFs required greater in vitro drug solubilization to elicit similar in vivo exposure when compared to previous studies with MC-LBF. Although post digestion solubilization was enhanced in LC-LBF compared to MC-LBF, equilibrium solubility studies of CP-532,623 in the aqueous phase isolated from blank lipid digestion experiments revealed that equilibrium solubility was also higher, and therefore supersaturation lower. A revised correlation based on supersaturation in the digest aqueous phase and drug absorption was therefore generated. A single, linear correlation was evident for both LC- and MC-LBF containing Kolliphor RH 40, but this did not extend to formulations based on other surfactants. The data suggest that solubilization and supersaturation are significant drivers of drug absorption in vivo, and that across formulations with similar formulation composition good correlation is evident between in vitro and in vivo measures. However, across dissimilar formulations, solubilization and supersaturation alone are not sufficient to explain drug exposure and other factors also likely play a role.

Potential of Excipient Emulsions for Improving Quercetin Bioaccessibility and Antioxidant Activity: An in Vitro Study.

The potential for excipient emulsions to enhance the bioaccessibility and antioxidant activity of quercetin was determined in this study. Oil-in-water excipient emulsions containing two levels (4 or 10%) of small lipid droplets (d < 250 nm) were prepared from a long-chain triglyceride (corn oil). The solubilization of quercetin by the excipient emulsions was faster than by bulk corn oil or bulk water, and the solubilization rate was higher at 100 °C than at 30 °C. The bioaccessibility of quercetin samples was determined using an in vitro gastrointestinal model, and the bioactivity of quercetin was determined using a rat feeding study. The excipient emulsions were more effective at enhancing quercetin bioaccessibility and rat plasma antioxidant activity than either bulk oil or bulk water. This effect was attributed to the rapid digestion of the long chain triglycerides when they were in an emulsified form, which led to the rapid production of mixed micelles capable of solubilizing, protecting, and transporting quercetin.

Correlation of Phosphorus Cross-Linking to Hydration Rates in Sodium Starch Glycolate Tablet Disintegrants Using MRI.

Understanding the behavior of tablet disintegrants is valuable in the development of pharmaceutical solid dosage formulations. In this study, high-resolution magnetic resonance imaging has been used to understand the hydration behavior of a series of commercial sodium starch glycolate (SSG) samples, providing robust estimates of tablet disintegration rate that could be correlated with physicochemical properties of the SSGs, such as the extent of phosphorus (P) cross-linking as obtained from infra-red spectroscopy. Furthermore, elemental analysis together with powder X-ray diffraction has been used to quantify the presence of carboxymethyl groups and salt impurities, which also contribute to the disintegration behavior. The utility of Fast Low Angle SHot magnetic resonance imaging has been demonstrated as an approach to rapidly acquire approximations of the volume of a disintegrating tablet and, together with a robust voxel analysis routine, extract tablet disintegration rates. In this manner, a complete characterization of a series of SSG grades from different sources has been performed, showing the variability in their physicochemical properties and demonstrating a correlation between their disintegration rates and intrinsic characteristics. The insights obtained will be a valuable aid in the choice of disintegrant source as well as in managing SSG variability to ensure robustness of drug products containing SSG.

Enhancing Nutraceutical Bioavailability from Raw and Cooked Vegetables Using Excipient Emulsions: Influence of Lipid Type on Carotenoid Bioaccessibility from Carrots.

The influence of the nature of the lipid phase in excipient emulsions on the bioaccessibility and transformation of carotenoid from carrots was investigated using a gastrointestinal tract (GIT) model. Excipient emulsions were fabricated using whey protein as an emulsifier and medium-chain triglycerides (MCT), fish oil, or corn oil as the oil phase. Changes in particle size, charge, and microstructure were measured as the carrot-emulsion mixtures were passed through simulated mouth, stomach, and small intestine regions. Carotenoid bioaccessibility depended on the type of lipids used to form the excipient emulsions (corn oil > fish oil ≫ MCT), which was attributed to differences in the solubilization capacity of mixed micelles formed from different lipid digestion products. The transformation of carotenoids was greater for fish oil and corn oil than for MCT, which may have been due to greater oxidation or isomerization. The bioaccessibility of the carotenoids was higher from boiled than raw carrots, which was attributed to greater disruption of the plant tissue facilitating carotenoid release. In conclusion, excipient emulsions are highly effective at increasing carotenoid bioaccessibility from carrots, but lipid type must be optimized to ensure high efficacy.

An evaluation of the adhesion of solid oral dosage form coatings to the oesophagus.

There is a requirement for the development of oral dosage forms that are adhesive and allow extended oesophageal residence time for localised therapies, or are non-adhesive for ease of swallowing. This study provides an initial assessment of the in vitro oesophageal retention characteristics of several widely utilised pharmaceutical coating materials. To this end, a previously described apparatus has been used to measure the force required to pull a coated disc-shaped model tablet across a section of excised oesophageal tissue. Of the materials tested, the well-studied mucoadhesive polymer sodium alginate was found to be associated with significant oesophageal adhesion properties that was capable of 'self-repairing'. Hydroxypropylmethylcellulose exhibited less pronounced bioadhesive behaviour and blending this with plasticiser or with low molecular weight polymers and surfactants did not significantly affect this. Low molecular weight water soluble polymers, were found to behave similarly to the uncoated glass control disc. Polysorbates exhibited bioadhesion behaviour that was majorly influenced by the nature of the surfactant. The insoluble polymer ethylcellulose, and the relatively lipophilic surfactant sorbitan monooleate were seen to move more readily than the uncoated disc, suggesting that these may have a role as 'easy-to-swallow' coatings.

Designing excipient emulsions to increase nutraceutical bioavailability: emulsifier type influences curcumin stability and bioaccessibility by altering gastrointestinal fate.

The influence of emulsifier type on the ability of excipient emulsions to improve the solubility, stability, and bioaccessibility of powdered curcumin was examined. Oil-in-water emulsions prepared using three different emulsifiers (whey protein isolate, caseinate, or Tween 80) were mixed with curcumin powder and then incubated at either 30 °C (to simulate applications of salad dressings) or 100 °C (to simulate applications of cooking sauces). The transfer of curcumin into the excipient emulsions was appreciably higher for excipient emulsions held at 100 °C than those held at 30 °C, and was appreciably higher for surfactant-stabilized emulsions than protein-stabilized emulsions. For example, the amounts of curcumin transferred into emulsions held at 30 and 100 °C were 66 and 280 µg mL(-1) for Tween 80, but only 17 and 208 µg mL(-1) for caseinate. The total curcumin concentration in the digesta and mixed micelle phases collected after excipient emulsions were exposed to a simulated gastrointestinal tract (mouth, stomach, and small intestine) depended on emulsifier type. The total amount of curcumin within the digesta was higher for protein-stabilized emulsions than surfactant-stabilized ones, which was attributed to the ability of the proteins to protect curcumin from chemical degradation. For example, the digesta contained 204 µg mL(-1) curcumin for caseinate emulsions, but only 111 µg mL(-1) for Tween 80 emulsions. This study shows the potential of designing excipient emulsions to increase the oral bioavailability of curcumin for food and pharmaceutical applications.