Application of biosurfactants in enhanced oil recovery ex-situ: a review.

With a growing focus on environmentally friendly solutions, biosurfactants derived from plants or microorganisms have gained attention for Enhanced Oil Recovery (EOR) applications. Biosurfactants offer several advantages over existing options, including biodegradability, low toxicity, availability of raw materials, resistance to harsh reservoir conditions, and improved water/oil interfacial tension reduction. Different organisms, such as bacteria, fungi, and plants, can produce these natural surfactants.

Lipid nanoparticles containing coenzyme Q10 for topical applications: An overview of their characterization.

The coenzyme Q10 is a compound widely used in pharmaceutical and cosmetic formulations because it is a potent eliminator of free radicals, giving it antioxidant and anti-aging properties. It is naturally synthesized by the human body, but its production wanes with age, leading to the formation of wrinkles. The efficacy of topical application of the coenzyme to counteract this process is subject to several difficulties, due to its instability in the presence of light, low solubility in water and high lipophilicity.

Development of purified cashew gum mucoadhesive buccal tablets containing nystatin for treatment of oral candidiasis.

Objective: The objective of this work was to prepare mucoadhesive buccal tablets containing nystatin and purified cashew gum for the treatment of oral candidiasis.

Significance: Mucoadhesive buccal tablets containing the drug nystatin are an alternative to oral suspensions, which cause low therapeutic adherence to the treatment of oral candidiasis. Purified cashew gum has been studied as a diluent and mucoadhesive agent in tablets.

Hybrid Vesicular Nanosystems Based on Lipids and Polymers Applied in Therapy, Theranostics, and Cosmetics.

Nanotechnology has made great contributions in the development of materials with potential application in different areas, especially in the pharmaceutical sector, where nano-systems are being intensely studied for controlled drug release. These innovative systems are composed of structures such as nanoparticles, nanoemulsions, and cyclodextrins, with the aim of promoting enhanced bioavailability of bioactive molecules. Among these nanocarriers, vesicles such as liposomes and polymersomes are considered to be promising alternatives in delivering hydrophilic and lipophilic drugs.

Synthesis of Hydrogel Nanocomposites Based on Partially Hydrolyzed Polyacrylamide, Polyethyleneimine, and Modified Clay.

Polymeric gels have been an important category for material scientists due its versatile structural features. Hence, hydrogels are being used to reduce excess production water in oil reservoirs. In this work, cross-linked partially hydrolyzed polyacrylamide (HPAM) composite hydrogels impregnated with bentonite clay (Bent) and bentonite clay modified (Orgbentent) with the surfactant hexadecyltrimethylammonium bromide were synthesized and characterized as a sealing agent in high water producing permeable zones in the petroleum industry.

Multiple Response Optimization of Beeswax-Based Nanostructured Lipid Carriers for the Controlled Release of Vitamin E.

Consumer demand for cosmetics is growing, causing a need to develop new systems to release active ingredients. Among these, nanostructured lipid carriers (NLCs) have certain advantages regarding penetration of active compounds in the skin. The study reported here aimed to develop an NLC system for controlled release of vitamin E, a substance that has antioxidant and photoprotective properties.

Development of Oil-in-Water Microemulsions and Evaluation of Its Presence in the Treatment of Produced Water.

Enhanced oil recovery (EOR) by chemical methods, such as injection of surfactants and polymers, increases the efficiency of extracting petroleum. However, after permeating the reservoir, these products remain in the produced water and hamper its treatment, including the efficiency reduction of the flocculants normally used for this purpose. In this work, oil-in-water (O/W) microemulsions were prepared according to ternary phase diagrams, with two oil phases, solbrax and kerosene, extracted from oil fractions, and two ethoxylated nonylphenol surfactants with 8 and 9.

Nanovesicle-based formulations for photoprotection: a safety and efficacy approach.

Vesicular nanosystems are versatile and they are able to encapsulate actives with different solubilities, such as lipophilic and hydrophilic compounds. The most well-known vesicular nanosystems are liposomes and niosomes, the last one is formed by non-ionic surfactants. In the present work, we developed photoprotective niosomes containing sunscreens (octyl methoxycinnamate, diethylamino hydroxybenzoyl hexyl benzoate and phenylbenzimidazole sulfonic acid), non-ionic surfactants, cholesterol and stearylamine (positive-charged lipid).

Gelation Kinetics of Hydrogels Based on Acrylamide⁻AMPS⁻NVP Terpolymer, Bentonite, and Polyethylenimine for Conformance Control of Oil Reservoirs.

Relatively smaller volumes of gelling systems had been used to address conformance problems located near the wellbore in oil reservoirs with harsh temperature and salinity conditions. These gelling systems were formulated with high concentrations of low-molecular-weight acrylamide-based polymers crosslinked with polyethylenimine (PEI). However, for in-depth conformance control, in which large gelant volumes and long gelation times were required, lower-base polymer loadings were necessary to ensure the economic feasibility of the treatment.

Dual alginate-lipid nanocarriers as oral delivery systems for amphotericin B.

Amphotericin B (AmB) is the first-choice drug to treat several fungal infections. However, due to its low solubility it can only be administrated intravenously. Nanostructured lipid carriers (NLC) have the ability to encapsulate hydrophobic drugs in an aqueous matrix, making them interesting for use in alternative drug delivery systems for AmB.

Hydrogel-thickened nanoemulsions based on essential oils for topical delivery of psoralen: Permeation and stability studies.

Nanoemulsions (NE) have attracted much attention due to their as dermal delivery systems for lipophilic drugs such as psoralens. However, NE feature low viscosity which might be unsuitable for topical application. In this work, we produced hydrogel-thickened nanoemulsions (HTN) using chitosan as thickening polymer to overcome the low viscosity attributed to NE.

Niosomes as Nano-Delivery Systems in the Pharmaceutical Field.

Nanosystems used in the pharmaceutical field aim to guarantee a controlled release and efficacy boost with dose reduction of the drug. The same active ingredient could be vehiculated in different concentrations in distinct nanosystems. Among these nanostructures, the vesicular ones present a versatile delivery system that could be applied to encapsulate lipophilic, amphiphilic, and hydrophilic compounds.

Nanosystems in Photoprotection.

The ultraviolet (UV) radiation is responsible for stimulating acute responses in the human skin, those including positive responses like vitamin D synthesis along with negative ones such as erythema. The chronic effects of UV radiation include photoaging and cancer. Sunscreens are classified as organic and inorganic and the safety of the products containing them is related to the evaluation of the effects of these actives on the skin (irritation and sensitization) and also the possibility of cutaneous permeation that may cause the product to permeate into the bloodstream, possibly generating systemic toxicity.

Polymer-based Drug Delivery Systems Applied to Insects Repellents Devices: A Review.

Insects-borne diseases constitute a public health concern. Since there is no vaccine or curative treatment for many of these diseases, individual protection is the main approach to prevent them. Nowadays, the search for replacing synthetic molecules for insect repellents from natural sources, such as essential oils, is increasing.

Development and Evaluation of Nanoemulsions Containing Phthalocyanines for Use in Photodynamic Cancer Therapy.

This work reports the development of oil in water (o/w) nanoemulsions containing poly(ethylene oxide)-poly(propylene oxide) block copolymer surfactant for the formulation of a delivery system for endovenous zinc and chloroaluminum phthalocyanines. A solubility study suggested clove oil and its combination with ethanol as the best candidates for the oil phase composition. The nanoemulsions were obtained using a high-pressure homogenizer and analyzed for droplet size to determine their short- and long-term stability.

Polymeric Nanostructured Systems for Liquid Formulation of Praziquan-tel: Development and in vitro Assessment.

Praziquantel (PZQ) is widely used in the treatment of several parasitic infections in both humans and animals, and is the first choice in the treatment of Schistosomiasis in humans. However, PZQ is a hydrophobic drug, and its low aqueous solubility has been a significant barrier to the development of oral liquid formulations that may provide improved bioavailability, pharmacokinetic profile, and compliance. The aim of this study was thus (i) to develop an oil-in-water (O/W) nanoemulsion(NE)-based platform for the delivery of PZQ in liquid form; (ii) to study the transport of PZQ formulated in NEs across an in vitro model of the intestinal epithelium; and (iii) to determine the toxicity profile of the NEs and their individual components on the model epithelium.

Development and characterization of micellar systems for application as insect repellents.

N,N-diethyl-meta-toluamide (DEET) is a widely used insect repellent due to its high efficacy. In this work, micellar systems based on poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer were developed and studied for the purpose of controlling the release and cutaneous permeation of DEET, using concentrated solutions of the copolymer Pluronic F127 to form thermoreversible gels. The formulations presented thermoreversible gelation above 5°C and altered rheological behavior at 15 and 25°C.

Determination of oil-in-water using nanoemulsions as solvents and UV visible and total organic carbon detection methods.

The aim of this study was to investigate the application of oil in water (O/W) nanoemulsion as solvent in the extraction step for determination of oil content in oily water, measured using a UV visible spectrophotometer (UV-vis) and a total organic carbon (TOC) analyzer. The optical micrographs and distribution size curves showed that the use of a small amount of nanoemulsion was capable of transforming the oily water in a colloidal dispersion that can be read in the UV-vis and TOC-VCHS devices. The oil content results obtained showed great accuracy between the measurements, with very low average standard deviation (∼5%) for both UV-vis and TOC-VCHS.

Characterization and evaluation of poly(epsilon-caprolactone) nanoparticles containing 2-ethylhexyl-p-methoxycinnamate, octocrylene, and benzophenone-3 in anti-solar preparations.

Ultraviolet radiation can bring both harm and benefits to human health. Among those harms are erythemas, photosensitivity, photoaging, and the most worrying, skin cancer. Nanoencapsulation of sunscreen agents (SA) by using a biocompatible and biodegradable polymer such as poly(epsilon-caprolactone) (PCL) is advantageous as it increases the retention of UV absorbers in the skin, avoids systemic absorption, and consequently, improves water resistance and stability of the preparation.

Nanoemulsions containing octyl methoxycinnamate and solid particles of TiO₂: preparation, characterization and in vitro evaluation of the solar protection factor.

The objective of this work was to develop and evaluate the physical-chemical properties of oil-in-water nanoemulsions for application as nanocosmetics for sun protection. Oil-in-water dispersions were processed by ultrasound (US) to obtain small emulsion droplets. These emulsions were obtained in the presence of commercial nonionic surfactants based on polyoxides and avocado oil as the oil phase.

The application of nanoemulsions with different orange oil concentrations to remediate crude oil-contaminated soil.

The petroleum industry stands out for causing significant environmental risks from contamination of the air, water and soil. The removal of organic pollutants from the environment poses a great technological challenge, making it increasingly necessary to develop efficient clean-up technologies. Surfactant solutions have been used to remediate soils and aquifers contaminated by hydrocarbons or crude oil derivatives.

Nanoemulsions as delivery systems for lipophilic drugs.

Nanoemulsions have received a growing attention as colloidal drug carriers for pharmaceutical applications. Their advantages over conventional formulations include drug enhanced solubility and bioavailability, protection from toxicity, improved pharmacological activity and stability, more sustained delivery and protection from physical and chemical degradation. Nanoemulsions can be prepared by two major techniques, high-energy and low-energy emulsification.

Stability of orange oil/water nanoemulsions prepared by the PIT method.

This article reports the preparation and characterization of orange oil/water nanoemulsions stabilized by commercial nonionic surfactants based on ethoxylated lauryl ether (Ultrol line), by the phase inversion temperature (PIT) method. The orange oil/surfactant/water dispersions were prepared at different HLB values, by varying the concentrations of the surfactants as well as the concentration of the oil phase. The stability of the o/w nanoemulsions and the size distribution of the dispersed particles in these systems in general depended on the concentration of the oil phase used: the emulsions prepared with an oil phase of 14 wt% had smaller droplet size in the dispersed phase than the emulsions prepared in the presence of oil phases of 20 and 30 wt%.

Influence of the hydrotrope structure on the physical chemical properties of polyoxide aqueous solutions.

The physical chemical properties of block substituted poly(ethylene oxide-propylene oxide) (PEO-PPO) block copolymer aqueous solutions were evaluated in the presence of two hydrotropes of different structures: sodium p-toluene sulfonate (NaPTS) and butyl monoglycol sodium sulfonate (NaBMGS). The critical micelle concentration and the cloud point of the copolymer solutions were displaced to higher concentration values, indicating that the solubility of the copolymer was increased in the presence of the hydrotropes. Temperature increased the micelle hydrodynamic radius, but concentration had a limited effect.