Food gel-based systems for efficient delivery of bioactive ingredients: design to application.

Food gels derived from natural biopolymers are valuable materials with significant scientific merit in the food industry because of their biocompatibility, safety, and environmental friendliness compared to synthetic gels. These gels serve as crucial delivery systems for bioactive ingredients. This review focuses on the selection, formulation, characterization, and behavior in gastrointestinal of hydrogels, oleogels, and bigels as delivery systems for bioactive ingredients. These three gel delivery systems exhibit certain differences in composition and can achieve the delivery of different bioactive ingredients. Hydrogels are suitable for delivering hydrophilic ingredients. Oleogels are an excellent choice for delivering lipophilic ingredients. Bigels contain both aqueous and oil phases, whose gelation makes their structure more stable, demonstrating the advantages of the above two types of gels. Besides, the formation and properties of the gel system are confirmed using different characterization methods. Furthermore, the changing behavior (e.g., swelling, disintegration, collapse, erosion) of the gel structure in the gastrointestinal is also analyzed, providing an opportunity to formulate soft substances that offer better protection or controlled release of bioactive components. This can further improve the transmissibility and utilization of bioactive substances, which is of great significance.

The oxidative quality of bi-, oleo- and emulgels and their bioactives molecules delivery.

During recent years, the applicability of bi-, oleo- and emulgels has been widely studied, proving several advantages as compared to conventional fats, such as increasing the unsaturated fat content of products and being more sustainable for temperate regions as compared to tropical fats. Moreover, these alternative fat systems improve the nutritional profile, increase the bioavailability of bioactive compounds, and can be used as preservation films and markers for the inactivation of pathogens, while in 3D printing facilitate the obtaining of superior food products. Furthermore, bi-, oleo- and emulgels offer food industries efficient, innovative, and sustainable alternatives to animal fats, shortenings, margarine, palm and coconut oil due to the nutritional improvements. According to recent studies, gels can be used as ingredients for the total or partial replacement of saturated and trans fats in the meat, bakery and pastry industry. The evaluation of the oxidative quality of this gelled systems is significant because the production process involves the use of heat treatments and continuous stirring where large amounts of air can be incorporated. The aim of this literature review is to provide a synthesis of studies to better understand the interaction of components and to identify future improvements that can be applied in oil gelling technology. Generally, higher temperatures used in obtaining polymeric gels, lead to more oxidation compounds, while a higher concentration of structuring agents leads to a better protection against oxidation. Due to the gel network ability to function as a barrier against oxidation factors, gelled matrices are able to provide superior protection for the bioactive compounds. The release percentage of bioactive molecules can be regulated by formulating the gel matrix (type and concentration of structuring agents and type of oil). In terms of food products, future research may include the use of antioxidants to improve the oxidative stability of the reformulated products.

[Oleogels as prospective nutritional ingredients of lipid nature].

The composition of the lipid component of consumed foods affects the consumers' health. Fats are not only a source of essential fatty acids, but also participate in the formation of the organoleptic and rheological properties of foodstuffs. At the same time, fats are sources of saturated and trans-isomeric fatty acids, which excessive consumption is associated with the risk of cardiovascular diseases, and therefore, it is relevant to search for promising ways to replace such fats. The aim of this review is to summarize data from studies of oleogels as an alternative to such fats. Results. It has been shown that the prevalence of obesity in many countries, including Russia, remains an acute problem. At the same time, as a rule, in persons with obesity and cardiovascular diseases, the consumption of fat including saturated and trans-isomeric fatty acids is excessive. To reduce the content of saturated and trans-isomeric fatty acids in foodstuffs, such systems as oleogels have recently been considered. The interest in these systems is related to the fact that they can act not only as substitutes for solid fats - sources of trans- and saturated fats but also as carriers of biologically active substances. Conclusion. The results of the analytical study indicate that active research is currently underway concerning the properties of oleogels, their use in foodstuffs, and modeling the effect of consumption of oleogels and containing them foodstuffs on the general metabolic health of humans. These studies are currently in their initial stages, but their results already indicate the great potential of oleogels as a food ingredient.

Diclofenac diethylamine nanosystems-loaded bigels for topical delivery: development, rheological characterization, and release studies.

The objective of this study was to develop novel topical drug delivery systems of the nonsteroidal anti-inflammatory drug diclofenac diethylamine (DDEA). Toward this objective, DDEA was loaded into two nanosystems, the oil in water (O/W) nanoemulsion (DDEA-NE) and the gold nanorods (GNR) that were conjugated to DDEA, forming DDEA-GNR. The DDEA-NE and DDEA-GNR were characterized in terms of particle size, zeta potential, morphology, thermodynamic stability, DDEA loading efficiency, and UV-Vis spectroscopy. These nanosystems were then incorporated into the biphasic gel-based formulations (bigels) for topical delivery. The rheological characterization and release studies of the DDEA NE- and DDEA GNR-incorporated bigels were performed and compared to those of DDEA traditional bigel. DDEA-NE exhibited a droplet size 15.2 ± 1.5 nm and zeta potential -0.37 ± 0.06 mV. The particle size of GNR was approximately 66 nm × 17 nm with an aspect ratio of approximately 3.8. The bigels showed composition-dependent viscoelastic properties, which in turn play a vital role in determining the rate and mechanism of DDEA release from the bigels. Bigels showed a controlled-release pattern where 61.6, 91.7, and 50.0% of the drug was released from DDEA traditional bigel, DDEA NE-incorporated bigel, and DDEA GNR-incorporated bigel, respectively, after 24 h. The ex vivo permeation studies showed that the amount of DDEA permeated through excised skin was relatively low, between 2.7% and 18.2%. The results suggested that the incorporation of the nanosystems NE and GNR into bigels can potentially improve the topical delivery of DDEA.

Novel Fish Oil-based Bigel System for Controlled Drug Delivery and its Influence on Immunomodulatory Activity of Imiquimod Against Skin Cancer.

PURPOSE: To characterize bigel system as a topical drug delivery vehicle and to establish the immunomodulatory role of imiquimod-fish oil combination against skin cancer and inflammation resulting from chemical carcinogenesis. METHODS: Imiquimod-loaded fish oil bigel colloidal system was prepared using a blend of carbopol hydrogel and fish oil oleogel. Bigels were first characterized for their mechanical properties and compared to conventional gel systems. Ex vivo permeation studies were performed on murine skin to analyze the ability of the bigels to transport drug across skin and to predict the release mechanism via mathematical modelling. Furthermore, to analyze pharmacological effectiveness in skin cancer and controlling imiquimod-induced inflammatory side effects, imiquimod-fish oil combination was tested in vitro on epidermoid carcinoma cells and in vivo in Swiss albino mice cancer model. RESULTS: Imiquimod-loaded fish oil bigels exhibited higher drug availability inside the skin as compared to individual imiquimod hydrogel and oleogel controls through quasi-Fickian diffusion mechanism. Imiquimod-fish oil combination in bigel enhanced the antitumor effects and significantly reduced serum pro-inflammatory cytokine levels such as tumor necrosis factor-alpha and interleukin-6, and reducing tumor progression via inhibition of vascular endothelial growth factor. Imiquimod-fish oil combination also resulted in increased expression of interleukin-10, an anti-inflammatory cytokine, which could also aid anti-tumor activity against skin cancer. CONCLUSION: Imiquimod administration through a bigel vehicle along with fish oil could be beneficial for controlling imiquimod-induced inflammatory side effects and in the treatment of skin cancer.

On the structural and mechanical properties of mixed coconut and olive oil oleogels and bigels.

The interaction of monoglycerides and phytosterols in olive- and coconut oil on the structuring of oleogels was analyzed. Specifically, bigels with gelatin hydrogel in different ratios (40:60 and 60:40 w/w) were formed. The physicochemical and microstructural attributes of these systems were assessed. The olive oil to coconut oil ratio (0-100 w/w) and the added oleogelators affected the crystal structure and the mechanical properties of the oleogels. Polarized light microscopy revealed that the addition of coconut oil created a denser triglycerides crystal network and the presence of phytosterols created more needle-like crystals, enhancing the textural properties of the oleogels and of the resulting bigels. The hardness of the oleogels ranged from 0.50 N to 1.24 N and for bigels was 5.96-36.75 N. Bigels hardness decreased as the oleogel ratio in the bigel increased. Microscopy and FTIR revealed that the addition of coconut oil in oleogels hampered the formation of a distinct crystalline monoglycerides network. Also, the absence of new peaks in the bigels indicated that the two structured phases interact with each other mostly physically, without the formation of new chemical bonds. Consequently, the oleogels and bigels developed, comprise a promising hard fat substitute with improved nutritional profile.

Chocolates, compounds and spreads: A review on the use of oleogels, hydrogels and hybrid gels to reduce saturated fat content.

This study is a bibliometric analysis and literature review on the use of oleogels (OGs), hydrogels (HGs) and hybrid gels (HYGs) in chocolate, compounds and spreads with the aim of reducing the saturated fat in these products. The articles were selected by analyzing titles, keywords and abstracts in the Web of Science (WoS), Scopus and Google Scholar databases. Supplementary documents were obtained from government sources, including patent registrations. The theoretical and practical aspects were critically analyzed, highlighting the main points of agreement and disagreement between the authors. The results revealed a lack of regulations and official guidelines that widely allow the use of OGs, HGs and HYGs in chocolate confectionery products. The type and characteristics of raw materials affect the properties of products. Replacing cocoa butter (CB) with OGs, HGs or HYGs also affects texture, melting point and behavior, and nutritional aspects. These substitutions can result in products with better sensory acceptance and health benefits, such as reducing saturated fat and promoting cardiovascular health. However, it is important to find the ideal combination and proportions of components to obtain the desired properties in the final products.

Evaluation of bigel systems as potential substitutes to partially replace pork backfat in semi-dry sausages.

Bigels prepared with olive oil oleogels admixed with κ-carrageenan or κ-carrageenan and gelatin hydrogels (BG1 and BG2, respectively) were characterized with respect to microstructure and textural properties and were used as pork backfat alternatives in semi-dry sausages. Stable oleogel-in-hydrogel type bigels were formed, with BG2 having higher hardness values. Control sausages (CF) were formulated with 20% pork backfat and sausage treatments B1F and B2F had 50% of the pork backfat substituted by BG1 and BG2 bigels, respectively. Moisture, water activity, texture, microbial counts, sensorial and nutritional attributes of the resulting sausages were assessed during fermentation and after pasteurization and storage. Substituted sausages had increased weight loss, moisture, and water activity. Color evaluation revealed that the treatments with bigels exhibited the same trend in color formation and no differences were recorded in L* and a* values of the sausages. Total viable counts and lactic acid bacteria populations were not affected by the addition of bigel systems. Regarding the texture parameters, B2F semi-dry sausages exhibited similar values of hardness and cohesiveness to CF. Sausages formulated with bigels exhibited a reduction in energy (20%), fat (27%), saturated fatty acids (30%) and cholesterol (∼6%) content. B2F sausages had similar liking scores with CF, and they did not show any undesirable sensory attributes. The results demonstrate that bigels are a promising fat alternative to manufacture semi-dry meat products with lower fat content and a better nutritional profile.

Production of Novel Bigels from Cold Pressed Chia Seed Oil By-Product: Application in Low-Fat Mayonnaise.

The objective of this study was to produce an innovative bigel formulation by combining glycerol monostearate (GMS) oleogel with hydrogels stabilized by various agents, including cold pressed chia seed oil by-product gum (CSG), gelatin (G), and whey protein concentrate (WPC). The findings indicated that the choice of hydrogel influenced the rheological, textural, and microstructural properties of the bigels. The G' value of the bigel samples was higher than G″, indicating that all the bigels exhibited solid-like characteristics. In order to numerically compare the dynamic rheological properties of the samples, K' and K″ values were calculated using the power law model. K' values of the samples were found to be higher than K″ values. The K' value of bigel samples was significantly affected by the hydrogel (HG)/oleogel ratio (OG) and the type of stabilizing agent used in the hydrogel formulation. As the OG ratio of bigel samples increased, the K' value increased significantly (p < 0.05). The texture values of the samples were significantly affected by the HG/OG ratio (p < 0.05). The study's findings demonstrated that utilizing CSG, G, and WPC at an OG ratio more than 50% can result in bigels with the appropriate hardness and solid character. The low-fat mayonnaise was produced by using these bigels. The low-fat mayonnaise showed shear-thinning and solid-like behavior with G' values greater than the G″ values. Low-fat mayonnaise produced with CSG bigels (CSGBs) showed similar rheological properties to the full-fat mayonnaise. The results showed that CSG could be used in a bigel formulation as a plant-based gum and CSGB could be used as a fat replacer in low-fat mayonnaise formulation.

Balancing competing objectives in bigel formulations using many-objective optimization algorithms and different decision-making methods.

Many-objective optimization, which deals with balancing multiple competing objectives to find compromised solutions, is essential for solving complex problems. This study explores evolutionary algorithms for optimizing the microstructural, rheological, stability, and drug release properties of bigel systems formulated using structured almond oil, mixed organogelators, and carbopol. The oleogel was identified as the dispersed phase, with droplet sizes ranging from 1.43 µm to 7.37 µm, indicating improved characteristics compared to other bigels. Each formulation exhibited non-Newtonian shear-thinning and thixotropic behaviors, which were positively influenced by the proportions of the excipients. After undergoing multiple stress cycles, highly concentrated bigels exhibited phase separation. Unexpectedly, bigels with lower viscosity exhibited reduced rates of drug release. FT-IR and HPLC analyses confirmed the compatibility and stability of drug-excipient interactions, with impurities remaining below 4%. This study emphasizes the complex interactions within mixed lipid-based bigels, requiring many-objective optimization techniques to address conflicting objectives. The objectives of optimization involve simultaneously minimizing microstructural properties while maximizing structural recovery and drug release properties. This led to conflicting objectives, where achieving higher structural recovery did not align with the desired drug release rate. Additionally, more stable formulations did not meet the optimal microstructural objectives. To resolve these conflicts, an RSM-MaOEAs approach was applied, employing various decision-making methods. Among EAs, RSM-RVEA notably achieved exceptional convergence. Furthermore, three MaOEAs-integrated decision-making methods-WSM, WPM, NED-and the RSM-desirability, offered potential solutions. Overall, this research proposes a robust framework for compromising the bigels' performance and stability, with broader applications in drug delivery and related fields.

Flexible control of bigel microstructure for enhanced stability and flavor release during oral consumption.

Edible delivery systems such as emulsions and gels that possess flexible oral flavor sensation and comprehensive stability under freeze-thaw processing are highly demanded in the frozen food industry. Bigels were fabricated via emulsification of stearic acid based oleogel with konjac glucomannan (KGM)-gelatin (G) based binary hydrogel. By varing the KGM/G mass ratio (γ) and oleogel/hydrogel volume ratio (φ) of bigels, modulation over the micromorphology, tribology, flavor sensation and cheese stick imitating capacity were achieved. Notably, as φ increased from O4:W6 to O5:W5, the microstructural transformation from oleogel-in-hydrogel to bicontinuous morphology emerged as a remarkable feature. The influence of γ was evident in bicontinuous bigels, significantly enhancing water holding capacity (WHC) by 3.38-fold as γ transitioned from 1KGM:5G to 6KGM:5G during freeze-thaw cycles. φ and γ both played pivotal roles in altering the microstructure and rheological properties of the bigels, enabling customizable release of bioactive components and flavor perception. Oleogel-in-hydrogel bigels effectively prevented bioactive compound leakage during freeze-thaw conditions, while bicontinuous bigels demonstrated sustained flavor release during oral mastication. Release behaviors were dual-controlled by φ and γ, reducing oil-soluble flavor release with increased φ and lowering hydrophilic volatile release with elevated γ. Moreover, bigel-based cheese sticks showcased lower viscosity, higher creep recovery rates, and enhanced mouthfeel during minimal oral chewing, suggesting their potential in mimicking the properties of commercial counterparts. These findings extend insights into bigel design for tailored flavor release and bioactive preservation in food products.

Bigels as Delivery Systems: Potential Uses and Applicability in Food.

Bigels have been mainly applied in the pharmaceutical sector for the controlled release of drugs or therapeutics. However, these systems, with their intricate structures, hold great promise for wider application in food products. Besides their classical role as carrier and target delivery vehicles for molecules of interest, bigels may also be valuable tools for building complex food structures. In the context of reducing or even eliminating undesirable (but often highly functional) food components, current strategies often critically affect food structure and palatability. The production of solid fat systems that are trans-fat-free and have high levels of unsaturated fatty acids is one of the challenges the food industry currently faces. According to recent studies, bigels can be successfully used as ingredients for total or partial solid fat replacement in complex food matrices. This review aims to critically assess current research on bigels in food and pharmaceutical applications, discuss the role of bigel composition and production parameters on the characteristics of bigels and further expand the use of bigels as solid fat replacers and functional food ingredients. The hydrogel:oleogel ratio, selected gelators, inclusion of surfactants and encapsulation of molecules of interest, and process parameters (e.g., temperature, shear rate) during bigel production play a crucial role in the bigel's rheological and textural properties, microstructure, release characteristics, biocompatibility, and stability. Besides exploring the role of these parameters in bigel production, future research directions for bigels in a food context are explored.

Elevating meat products: Unleashing novel gel techniques for enhancing lipid profiles.

Rising health concerns and the diet-health link drive demand for healthier foods, prompting meat manufacturers to reformulate traditional products. These manufacturers have reduced fat content to enhance nutritional quality, which is essential for maintaining desired product features. As a result, numerous strategies have emerged over recent decades to decrease fat and enhance the lipid profiles of meat products. Among these strategies, using hydrocolloids, emulsification, encapsulation, or gelation of oils to produce fat substitutes stands out. Using gels allows fat replacers with characteristics similar to animal fat (similar rheological, physical, or appearance properties) but with a much healthier lipid profile (by incorporating highly unsaturated oils). Therefore, this manuscript aims to comprehensively describe the main fat replacers used to prepare meat products. In addition, an in-depth review of the latest studies (2022-2023) that use novel gels to reform meat products has been made, indicating in each case the implications that the reformulation produces at a physicochemical, nutritional, and sensory level. Given the reported results, it seems clear that the strategy of using bigels or emulgels is very promising and allows obtaining nutritionally highly improved meat products without affecting their sensory or physicochemical properties. However, the best conditions to obtain a novel gel suitable for use as a fat substitute for each meat product still need to be studied and correctly defined. Moreover, these advancements can pave the way for more extensive studies on using novel gel techniques in other food industries, expanding their applicability and leading to healthier consumer options across various food categories.

Bigels as Fat Replacers in Fermented Sausages: Physicochemical, Microbiological, Sensory, and Nutritional Characteristics.

Olive oil bigels structured with monoglycerides, gelatin, and κ-carrageenan were designed for the partial substitution of pork backfat in fermented sausages. Two different bigels were used: bigel B60 consisted of 60% aqueous and 40% lipid phase; and bigel B80 was formulated with 80% aqueous and 20% lipid phase. Three different pork sausage treatments were manufactured: control with 18% pork backfat; treatment SB60 with 9% pork backfat and 9% bigel B60; and treatment SB80 with 9% pork backfat and 9% bigel B80. Microbiological and physicochemical analyses were carried out for all three treatments on 0, 1, 3, 6, and 16 days after sausage preparation. Bigel substitution did not affect water activity or the populations of lactic acid bacteria, total viable counts, Micrococcaceae, and Staphylococcacea during the fermentation and ripening period. Treatments SB60 and SB80 presented higher weight loss during fermentation and higher TBARS values only on day 16 of storage. Consumer sensory evaluation did not identify significant differences among the sausage treatments in color, texture, juiciness, flavor, taste, and overall acceptability. The results show that bigels can be utilized for the formulation of healthier meat products with acceptable microbiological, physicochemical, and organoleptic characteristics.

Ultrasonic Treatment of Food Colloidal Systems Containing Oleogels: A Review.

The use of oleogels as an alternative to solid fats to reduce the content of saturated and trans-isomeric fatty acids is a developing area of research. Studies devoted to the search for methods of obtaining oleogels with given properties are of current interest. Ultrasonic treatment as a method for modifying oleogel properties has been used to solve this problem. The number of publications on the study of the effect of ultrasonic treatment on oleogel properties is increasing. This review aimed to systematize and summarize existing data. It allowed us to identify the incompleteness of this data, assess the effect of ultrasonic treatment on oleogel properties, which depends on various factors, and identify the vector of this direction in the food industry. A more detailed description of the parameters of ultrasonic treatment is needed to compare the results between various publications. Ultrasonic treatment generally leads to a decrease in crystal size and an increase in oil-binding capacity, rheological properties, and hardness. The chemical composition of oleogels and the concentration of gelators, the amplitude and duration of sonication, the cooling rate, and the crystallization process stage at which the treatment occurs are shown to be the factors influencing the efficiency of the ultrasonic treatment.

Bigels as drug delivery systems: From their components to their applications.

Bigels are systems that usually result from mixing a hydrogel and an organogel: the aqueous phase is commonly formed by a hydrophilic biopolymer, whereas the organic phase comprises a gelled vegetable oil because of the presence of an organogelator. The proportion of the corresponding gelling agent in each phase, the organogel/hydrogel ratio, and the mixing temperature and speed all need to be taken into consideration for bigel manufacturing. Bigels, which are particularly useful drug delivery systems, have already been formulated for transdermal, buccal, and vaginal routes. Mechanical assessments and microscopy are the most reported characterization techniques. As we review here, their composition and unique structure confer promising drug delivery attributes, such as mucoadhesion, the ability to control drug release, and the possibility of including both hydrophilic and lipophilic drugs in the same system.

Development and characterization of novel bigels based on monoglyceride-beeswax oleogel and high acyl gellan gum hydrogel for lycopene delivery.

The aim of present study was to develop novel bigels as a semi-solid vehicle for lycopene delivery. Bigels were prepared by using the mixture of glycerol monostearate (GMS)-beeswax based oleogel and high acyl gellan gum hydrogel in different proportions. The confocal microscopic observations showed that the obtained bigels were oleogel-in-hydrogel, and droplets became larger with increased contents of oleogel. Higher fractions of oleogel increased the mechanical strength (storage modulus, firmness) of bigels. According to the rheological results, all bigels exhibited solid-like characteristics since the storage modulus were larger than loss modulus. DSC results showed that the melting temperature of bigel was higher than that of oleogel. During in vitro simulated gastrointestinal digestion, the total release percentages varied from 60% to 80%, and a higher content of oleogel within bigels could slower down the release of lycopene, suggesting that a higher proportion of oleogel was beneficial for delivery of fat-soluble nutraceuticals.

Interfacial and Bulk Stabilization of Oil/Water System: A Novel Synergistic Approach.

Oil/water emulsions are usually stabilized either by interfacial modification using nanoparticles and surfactants (stated as pickering emulsion or bijels) or by bulk stabilization with the help of low-molecular-weight or polymeric gelators (known as bigels) in response to some external stimuli (e.g., pH, temperature). Both these approaches result in different systems that are quite useful for different applications, including catalysis, pharmaceutical and agrochemicals. However, these systems also possess some inherent drawbacks that need to be addressed, like difficulty in fabrication and ensuring the permanent binding of nanoparticles at the oil/water interface, in case of nanoparticles stabilized emulsions (i.e., interfacial stabilization). Similarly, the long-term stability of the oil/water systems produced by using (hydro/organo) gelators (i.e., bulk stabilization) is a major concern. Here, we show that the oil/water system with improved mechanical and structural properties can be prepared with the synergistic effect of interfacial and bulk stabilization. We achieve this by using nanoparticles to stabilize the oil/water interface and polymeric gelators to stabilize the bulk phases (oil and water). Furthermore, the proposed strategy is extremely adaptable, as the properties of the resultant system can be finely tuned by manipulating different parameters such as nanoparticles content and their surface functionalization, solvent type and its volume fraction, and type and amount of polymeric gelators.

Key characteristics and modelling of bigels systems: A review.

Bigels are interesting semisolid formulations with better properties for different applications such as cosmetics and pharmaceutical systems. Due to the mixing of two phases of different nature (polar and apolar), bigels possess some interesting features like ability to deliver hydrophilic and hydrophobic drugs, better spreadability and water washability, improved permeability of drugs, enhanced hydration of stratum corneum and ability to manipulate the drug release rate. The main objective of this review article is to provide a thorough insight into the important characteristics of bigels together with the discussion on modelling of bigel systems to relate their properties with individual constituents and different parameters. Moreover, some important applications of bigels are also discussed by considering some examples from the literature.

Smart Freeze-Dried Bigels for the Prevention of the Sexual Transmission of HIV by Accelerating the Vaginal Release of Tenofovir during Intercourse.

Sub-Saharan African women are still at risk from the human immunodeficiency virus (HIV), and sex with men is the main route of transmission. Vaginal formulations containing antiretroviral drugs are promising tools to give women the power to protect themselves. The aim of this work was to obtain freeze-dried bigels containing pectin, chitosan, or hypromellose for the vaginal controlled release of Tenofovir, which is accelerated in the presence of semen. Nine batches of bigels were formulated using different proportions of these polymers in the hydrogel (1, 2, and 3% w/w). The bigels obtained were freeze-dried and then underwent hardness and deformability, mucoadhesion, swelling, and drug release tests, the last two in simulated vaginal fluid (SVF) and SVF/simulated seminal fluid (SSF) mixture. The formulation containing 3% pectin (fd3P) has the highest values for hardness, resistance to deformation, and good mucoadhesivity. Its swelling is conditioned by the pH of the medium, which is responsive to the controlled release of Tenofovir in SVF, with the fastest release in the SVF/SSF mixture. fd3P would be an interesting smart microbicidal system to allow faster release of Tenofovir in the presence of semen, and thus increase women's ability to protect themselves from the sexual transmission of HIV.