Dual function surfactants for pharmaceutical formulations: The case of surface active and antibacterial 1-tolyl alkyl biguanide derivatives.

One interesting field of research in the view of developing novel surfactants for pharmaceutical and cosmetic applications is the design of amphiphiles showing further bioactive properties in addition to those commonly displayed by surface-active compounds. We propose here the chemical synthesis, and characterization of 1-o-tolyl alkyl biguanide derivatives, having different lengths of the hydrocarbon chain (C3, C6, and C10), and showing surface active and antibacterial/disinfectant activities toward both Gram-positive and Gram-negative bacteria. Both surface active properties in terms of critical micelle concentration (CMC) and surface tension at CMC (γCMC), as well as the antimicrobial activity in terms of minimum inhibitory concentrations (MICs), were strongly dependent on the length of the hydrocarbon chain. Particularly, the C6 and C10 derivatives have a good ability to decrease surface tension (γCMC <40 mN/m) at low concentrations (CMC < 12 mM) and a satisfactory antibacterial effect (MIC values between 0.230 and 0.012 mM against S. aureus strains and between 0.910 and 0.190 against P.aeruginosa strains). Interestingly, these compounds showed a disinfectant activity at the tested concentrations that was comparable to that of the reference compound chlorhexidine digluconate. All these results support the possible use of these amphiphilic compounds as antibacterial agents and disinfectants in pharmaceutical or cosmetic formulations.

Deciphering the Lipid-Random Copolymer Interactions and Encoding Their Properties to Design a Hybrid System.

Lipid/copolymer colloidal systems are deemed hybrid materials with unique properties and functionalities. Their hybrid nature leads to complex interfacial phenomena, which have not been fully encoded yet, navigating their properties. Moving toward in-depth knowledge of such systems, a comprehensive investigation of them is imperative. In the present study, hybrid lipid/copolymer structures were fabricated and examined by a gamut of techniques, including dynamic light scattering, fluorescence spectroscopy, cryogenic transmission electron microscopy, microcalorimetry, and high-resolution ultrasound spectroscopy. The biomaterials that were mixed for this purpose at different ratios were 1,2-dioctadecanoyl-sn-glycero-3-phosphocholine and four different linear, statistical (random) amphiphilic copolymers, consisting of oligo(ethylene glycol) methyl ether methacrylate as the hydrophilic comonomer and lauryl methacrylate as the hydrophobic one. The colloidal dispersions were studied for lipid/copolymer interactions regarding their physicochemical, morphological, and biophysical behavior. Their membrane properties and interactions with serum proteins were also studied. The aforementioned techniques confirmed the hybrid nature of the systems and the location of the copolymer in the structure. More importantly, the random architecture of the copolymers, the hydrophobic-to-hydrophilic balance of the nanoplatforms, and the lipid-to-polymer ratio are highlighted as the main design-influencing factors. Elucidating the lipid/copolymer interactions would contribute to the translation of hybrid nanoparticle performance and, thus, their rational design for multiple applications, including drug delivery.

PEO-b-PCL/Tween 80/cyclodextrin systems: from bioinspired fabrication to possible nasal administration of ropinirole hydrochloride.

In this study, we designed and developed systems composed of poly(ethylene-oxide)-b-poly(ε-caprolactone) block copolymers of different molecular weights and compositions, non-ionic surfactant, and cyclodextrins. The innovation of this study lies in the combination of these diverse biomaterials to create biomimetic and bioinspired drug delivery supramolecular structures. The systems were formed by the thin-film hydration method. Extensive physicochemical and morphological characterization was conducted using differential scanning calorimetry, light scattering techniques, microcalorimetry analysis, high-resolution ultrasound spectroscopy, surface tension measurements, fluorescence spectroscopy, cryogenic transmission electron microscopy images, and in vitro cytotoxicity evaluation. These innovative hybrid nanoparticles were found to be attractive candidates as drug delivery systems with unique properties by encompassing the physicochemical and thermotropic properties of both classes of materials. Subsequently, Ropinirole hydrochloride was used as a model drug for the purpose of this study. These systems showed a high RH content (%), and in vitro diffusion experiments revealed that more than 90% of the loading dose was released under pH and temperature conditions that simulate the conditions of the nasal cavity. Promising drug release performance was observed with all tested formulations, worth further investigation to explore both ex vivo permeation through the nasal mucosa and in vivo performance in an experimental animal model.

Exploring Immersion Coating as a Cost-Effective Method for Small-Scale Production of Enteric-Coated Gelatin Capsules.

The coating process for solid dosage forms is widely used in the pharmaceutical industry but presents challenges for small-scale production, needed in personalized medicine and clinical or galenic settings. This study aimed to evaluate immersion coating, a cost-effective small-scale method, for enteric-coated gelatin capsules using standard equipment. Two enteric coating polymers and different polymer concentrations were tested, along with API solubility. Results were compared with commercially available enteric capsule shells. Successful preparation of enteric coating capsules via immersion necessitates a comprehensive grasp of API and enteric polymer behavior. However, utilizing commercially available enteric capsule shells does not guarantee ease or robustness, as their efficacy hinges on the attributes of the active ingredient and excipients. Notably, coating with Eudragit S100 stands out for its superior process robustness, requiring minimal or no development time, thus representing the best option for small-scale enteric capsule production.

Enteral Delivery of Pravastatin Sodium Tablets: Effect of Compounding into a Liquid Form and Co-Administration of Enteral Nutrition.

BACKGROUND: Compounding solid oral dosage forms into liquid preparations is a common practice for administering drug therapy to patients with swallowing difficulties. This is particularly relevant for those on enteral nutrition, where factors such as the administration procedure and co-administration of enteral nutrition play crucial roles in effective drug delivery. Due to the limited studies focused on this practice, the impact of co-administered nutrition remains unclear. METHODS: Pravastatin tablets were compounded into two liquid formulations and administered through three independent tubes for ten cycles. The drug amount was quantified upstream and downstream of the tubes both with and without different (fiber content) nutritional boluses. RESULTS: The compounding procedure did not lower the drug amount with respect to the original tablets. However, when the liquid formulation was pumped through the tubes, a statistically significant reduction in the pravastatin administered (between 4.6% and 11.3%) was observed. The co-administration of different nutritional boluses or the compounding procedure did not affect the general results. CONCLUSIONS: Pravastatin loss appears unavoidable when administered via the enteral tube. Although, in this case, the loss was of limited clinical relevance, it is important not to underestimate this phenomenon, especially with drugs having a narrow therapeutic index.

Fabricating Polymer/Surfactant/Cyclodextrin Hybrid Particles for Possible Nose-to-Brain Delivery of Ropinirole Hydrochloride: In Vitro and Ex Vivo Evaluation.

Ropinirole is a non-ergolinic dopamine agonist used to manage Parkinson's disease and it is characterized by poor oral bioavailability. This study aimed to design and develop advanced drug delivery systems composed of poloxamer 407, a non-ionic surfactant (Tween 80), and cyclodextrins (methyl-ß-CD or hydroxy-propyl-ß-CD) for possible brain targeting of ropinirole after nasal administration for the treatment of Parkinson's disease. The hybrid systems were formed by the thin-film hydration method, followed by an extensive physicochemical and morphological characterization. The in vitro cytotoxicity of the systems on HEK293 cell lines was also tested. In vitro release and ex vivo mucosal permeation of ropinirole were assessed using Franz cells at 34 °C and with phosphate buffer solution at pH 5.6 in the donor compartment, simulating the conditions of the nasal cavity. The results indicated that the diffusion-controlled drug release exhibited a progressive increase throughout the experiment, while a proof-of-concept experiment on ex vivo permeation through rabbit nasal mucosa revealed a better performance of the prepared hybrid systems in comparison to ropinirole solution. The encouraging results in drug release and mucosal permeation indicate that these hybrid systems can serve as attractive platforms for effective and targeted nose-to-brain delivery of ropinirole with a possible application in Parkinson's disease. Further ex vivo and in vivo studies to support the results of the present work are ongoing.

Hydrogel containing mPEG-PLGA nanoparticles for the vaginal delivery of saquinavir mesylate against HIV infection.

Saquinavir mesylate (SQV) is a protease inhibitor commonly employed for the treatment of human immunodeficiency virus-1 infection. It is generally administered orally as tablets in combination with other antiviral drugs. Another promising route of administration can be represented by the vaginal one through topically applied formulations. This delivery can reduce the first-pass effect in the case of systemic drug adsorption or prevent HIV infection. We propose the formulation of a Carbopol® 974 (C974) hydrogel containing biodegradable mPEG-PL(L)GA nanoparticles (NPs) for the vaginal delivery of SQV, intended both as a prevention and a therapeutic strategy. mPEG-PL(L)GA NPs were incorporated into the C974 polymeric matrix, leading to a reduction of the hydrogel consistency dependent on NPs and C974 concentrations. Despite the moderate drug loading into NPs, the presence of the NPs had an impact on the in vitro release of the drug from the hydrogel at pH 5.5 using immersion cells. A higher amount of the drug was released, probably due to the effect of NPs in promoting the incorporation of the drug into the hydrogel at a high SQV dose. These findings can be useful for the development of topically applied hydrogels for SQV delivery, possibly having improved in vivo therapeutic outcomes.

Encapsulation of Hemp (Cannabis sativa L.) Essential Oils into Nanoemulsions for Potential Therapeutic Applications: Assessment of Cytotoxicological Profiles.

Industrial hemp (Cannabis sativa L.), due to its bioactive compounds (terpenes and cannabinoids), has gained increasing interest in different fields, including for medical purposes. The evaluation of the safety profile of hemp essential oil (EO) and its encapsulated form (nanoemulsion, NE) is a relevant aspect for potential therapeutic applications. This study aimed to evaluate the toxicological effect of hemp EOs and NEs from cultivars Carmagnola CS and Uso 31 on three cell lines selected as models for topical and inhalant administration, by evaluating the cytotoxicity and the cytokine expression profiles. Results show that EOs and their NEs have comparable cytotoxicity, if considering the quantity of EO present in the NE. Moreover, cells treated with EOs and NEs showed, in most of the cases, lower levels of proinflammatory cytokines compared to Etoposide used as a positive control, and the basal level of inflammatory cytokines was not altered, suggesting a safety profile of hemp EOs and their NEs to support their use for medical applications.

Quantification of Squalene and Lactic Acid in Hair Bulbs with Damaged Sheaths: Are They Metabolic Wastes in Alopecia?

Alopecia is a pathological and multifactorial condition characterised by an altered hair growth cycle and ascribed to different pathogenic causes. Cell energetic imbalances in hair follicles occurring in this disorder could lead to the production of some "metabolic wastes", including squalene and lactic acid, which could be involved in the clinically observed sheath damage. The aim of this work was the extraction and analytical quantification of squalene and lactic acid from hair bulbs of subjects with clinical alopecia in comparison with controls, using HPLC-DAD and HPLC-MS techniques. The analytical quantification was performed after a preliminary observation through a polarised optical microscope to assess sheath damage and morphological alterations in the cases group. A significantly larger amount of squalene was quantified only in subjects affected by alopecia (n = 31) and with evident damage to hair sheaths. For lactic acid, no statistically significant differences were found between cases (n = 21) and controls (n = 21) under the experimental conditions used. Therefore, the obtained results suggest that squalene can represent a metabolic and a pathogenic marker for some alopecia conditions.

Inulin Functionalized "Giuncata" Cheese as a Source of Prebiotic Fibers.

The development of functional foods in the dairy sector represents a flourishing field of technological research. In this study, an Italian fresh cheese as "giuncata" was enriched with inulin, a dietary fiber, with the aim of developing a product with improved nutritional properties in terms of prebiotic action on intestinal microbiota. An inulin concentration of ~4% w/w was determined in the fresh cheese after the fortification process, enabling the claim of being a "source of dietary fiber" (inulin > 3 g/100 g) according to the European regulation. The addition of inulin has no effect on the pH of cheese and does not relevantly influence its color as well as the total fat content (fat reduction ~0.61%) in comparison to the control. Mechanical properties of the cheese were also not markedly affected as evidenced from rheological and tensile testing analyses. Indeed, the incorporation of inulin in "giuncata" only exerts a slight "softening effect" resulting in a slightly lower consistency and mechanical resistance in comparison to the control. Overall, this study demonstrates the feasibility of producing a fiber-enriched dairy functional food from a large consumed fresh and soft cheese as "giuncata".

Sodium lauryl sulfate as lubricant in tablets formulations: Is it worth?

Lubricants are excipients used in tablet formulations to reduce friction and adhesion forces within the die or on the punches surface during the manufacturing process. Despite these excipients are always required for the tablets production, their amount must be carefully evaluated since lubricants can negatively impact on mechanical strength, disintegration and dissolution behavior of solid dosage forms. Alternative compounds have been suggested to overcome the issues of conventional lubricants and sodium lauryl sulfate (SDS) is one of the most promising one. Despite SDS has been object of several investigations, a definitive conclusion on its effectiveness cannot still be drawn. Particularly, its efficacy on tablets disaggregation and API dissolution is still unclear. Here, the effect of SDS on all the relevant features of tablets and tableting process has been evaluated on immediate release hydrophobic tablets formulations in comparison with conventional lubricants. The results of this investigation are quite outspoken: SDS has a low lubricant power while it determines only a limited improvement on tablets hardness. It greatly improves the tablets wettability but only on model formulations, the presence of superdisintegrants resets its effectiveness and any possible effect on tablets disaggregation. None of the tested formulations showed improvement on the API dissolution rate.

The Type of Grain Counts: Effectiveness of Three Essential Oil-Based Nanoemulsions against Sitophilus oryzae.

Essential oil (EO)-based nanoemulsions (NEs) are promising grain protectants in the management of stored-product pests. However, the potential impact of the stored-grain species on the green insecticide effectiveness has been poorly studied. In this study, two concentrations of EO-based NEs from Carlina acaulis L., Mentha longifolia (L.) Huds., and Hazomalania voyronii (Jum.) Capuron were evaluated as insecticides against the major stored-product pest Sitophilus oryzae (L.) on barley, oats, and maize kernels. The C. acaulis EO-based NE applied at 1000 ppm on barley achieved the highest mortality, killing 94.4% of S. oryzae adults after a 7-day exposure, followed by 1000 ppm of H. voyronii EO-based NE (83.3%). The lowest mortality (1.1%) was recorded with 500 ppm of M. longifolia EO-based NE on maize after the same interval. All tested NEs exhibited elevated efficacy when applied on barley, while mortalities were lower on oats and maize. Furthermore, C. acaulis EO-based NE was the most effective when applied on all commodities, followed by H. voyronii and M. longifolia EO-based NEs. Overall, our results highlighted the significant impact of the stored cereal on the insecticidal effectiveness of EO-based NE used for stored-product pest control. Sitophilus oryzae adults on barley can be adequately controlled through the application of C. acaulis and H. voyronii EO-based NEs.

Development of stimuli-responsive lyotropic liquid crystalline nanoparticles targeting lysosomes: Physicochemical, morphological and drug release studies.

The abilities of sub-cellular targeting and stimuli-responsiveness are critical challenges in pharmaceutical nanotechnology. In the present study, glyceryl monooleate (GMO)-based non-lamellar lyotropic liquid crystalline nanoparticles were stabilized by the poly(2-(dimethylamino)ethyl methacrylate)-b-poly(lauryl methacrylate) block copolymer carrying tri-phenyl-phosphine cations (TPP-QPDMAEMA-b-PLMA), either used alone or in combination with other polymers as co-stabilizers. The systems were designed to perform simultaneously sub-cellular targeting, stimuli-responsiveness and to exhibit stealthiness. The physicochemical characteristics and fractal dimensions of the resultant nanosystems were obtained from light scattering techniques, while their micropolarity and microfluidity from fluorescence spectroscopy. Their morphology was assessed by cryo-TEM, while their thermal behavior by microcalorimetry and high-resolution ultrasound spectroscopy. The analyzed properties, including the responsiveness to pH and temperature, were found to be dependent on the combination of the polymeric stabilizers. The subcellular localization was monitored by confocal microscopy, revealing targeting to lysosomes. Subsequently, resveratrol was loaded into the nanosystems, the entrapment efficiency was investigated and in vitro release studies were carried out at different conditions, in which a stimuli-triggered drug release profile was achieved. In conclusion, the proposed multi-functional nanosystems can be considered as potentially stealth, stimuli-responsive drug delivery nanocarriers, with targeting ability to lysosomes and presenting a stimuli-triggered drug release profile.

Non-Ionic Surfactant Effects on Innate Pluronic 188 Behavior: Interactions, and Physicochemical and Biocompatibility Studies.

The aim of this research was to prepare novel block copolymer-surfactant hybrid nanosystems using the triblock copolymer Pluronic 188, along with surfactants of different hydrophilic to lipophilic balance (HLB ratio-which indicates the degree to which a surfactant is hydrophilic or hydrophobic) and thermotropic behavior. The surfactants used were of non-ionic nature, of which Tween 80® and Brij 58® were more hydrophilic, while Span 40® and Span 60® were more hydrophobic. Each surfactant has unique innate thermal properties and an affinity towards Pluronic 188. The nanosystems were formulated through mixing the pluronic with the surfactants at three different ratios, namely 90:10, 80:20, and 50:50, using the thin-film hydration technique and keeping the pluronic concentration constant. The physicochemical characteristics of the prepared nanosystems were evaluated using various light scattering techniques, while their thermotropic behavior was characterized via microDSC and high-resolution ultrasound spectroscopy. Microenvironmental parameters were attained through the use of fluorescence spectroscopy, while the cytotoxicity of the nanocarriers was studied in vitro. The results indicate that the combination of Pluronic 188 with the above surfactants was able to produce hybrid homogeneous nanoparticle populations of adequately small diameters. The different surfactants had a clear effect on physicochemical parameters such as the size, hydrodynamic diameter, and polydispersity index of the final formulation. The mixing of surfactants with the pluronic clearly changed its thermotropic behavior and thermal transition temperature (Tm) and highlighted the specific interactions that occurred between the different materials, as well as the effect of increasing the surfactant concentration on inherent polymer characteristics and behavior. The formulated nanosystems were found to be mostly of minimal toxicity. The obtained results demonstrate that the thin-film hydration method can be used for the formulation of pluronic-surfactant hybrid nanoparticles, which in turn exhibit favorable characteristics in terms of their possible use in drug delivery applications. This investigation can be used as a road map for the selection of an appropriate nanosystem as a novel vehicle for drug delivery.

Green extraction of hemp (Cannabis sativa L.) using microwave method for recovery of three valuable fractions (essential oil, phenolic compounds and cannabinoids): a central composite design optimization study.

BACKGROUND: Solvent-free microwave-assisted extraction (MAE) is a green extraction method capable of boosting the yield and quality profile of hemp essential oil when compared with other conventional extraction techniques. During this process, two by-products are produced, namely the aqueous residue containing bioactive phenolics and the residual deterpenated biomass, which can be used for further extraction and purification of phytocannabinoids. To date, the hemp industry has not utilized these products, although they can be valuable for the food, cosmetic, nutraceutical and pharmaceutical market. RESULTS: This study assessed and optimized the variables affecting MAE efficiency, namely microwave irradiation power, extraction time and added water, which were studied using a central composite design approach, and results were used to optimize the extraction process for recovering three valuable fractions: essential oil, polyphenols and phytocannabinoids. The products obtained using the optimized conditions were characterized in terms of yield, chemical profile and antioxidant potential. Moreover, the by-products obtained during the optimized run were further analyzed in terms of their biological activity using both enzymatic and non-enzymatic assays. The aqueous residue demonstrated a powerful α-glucosidase inhibition, a good activity in terms of superoxide radical scavenging activity, a modest efficacy in terms of inhibition of advanced glycation end products formation and no activity in terms of lipase inhibition. The residual deterpenated biomass did not possess significant biological activity. CONCLUSION: This work demonstrated valorization of industrial hemp essential oil and its by-products, obtained by a sustainable and eco-friendly extraction method, through an almost waste-free approach. Cannabinoids as well as other valuable bioactive compounds such as glycosidic flavones may be recovered from the residues of the essential oil extraction, representing interesting substances in the pharmaceutical, cosmetic and nutraceutical fields. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

High-Resolution Ultrasound Spectroscopy for the Determination of Phospholipid Transitions in Liposomal Dispersions.

High-resolution ultrasound spectroscopy (HR-US) is a spectroscopic technique using ultrasound waves at high frequencies to investigate the structural properties of dispersed materials. This technique is able to monitor the variation of ultrasound parameters (sound speed and attenuation) due to the interaction of ultrasound waves with samples as a function of temperature and concentration. Despite being employed for the characterization of several colloidal systems, there is a lack in the literature regarding the comparison between the potential of HR-US for the determination of phospholipid thermal transitions and that of other common techniques both for loaded or unloaded liposomes. Thermal transitions of liposomes composed of pure phospholipids (dimyristoylphosphatidylcholine, DMPC; dipalmitoylphosphatidylcholine, DPPC and distearoylphosphatidylcholine, DSPC), cholesterol and their mixtures were investigated by HR-US in comparison to the most commonly employed microcalorimetry (mDSC) and dynamic light scattering (DLS). Moreover, tramadol hydrochloride, caffeine or miconazole nitrate as model drugs were loaded in DPPC liposomes to study the effect of their incorporation on thermal properties of a phospholipid bilayer. HR-US provided the determination of phospholipid sol-gel transition temperatures from both attenuation and sound speed that are comparable to those calculated by mDSC and DLS techniques for all analysed liposomal dispersions, both loaded and unloaded. Therefore, HR-US is proposed here as an alternative technique to determine the transition temperature of phospholipid membrane in liposomes.

Carlina acaulis essential oil nanoemulsion as a new grain protectant against different developmental stages of three stored-product beetles.

BACKGROUND: Plant essential oils (EOs) represent eco-friendly alternatives to conventional insecticides for managing pest populations. Carlina acaulis root EO showed a wide insecticidal spectrum, being highly effective against insect pests and vectors, coupled with low mammal toxicity. To boost the chemico-physical properties of this EO and its main active ingredient, carlina oxide, C. acaulis EO was encapsulated in a nanoemulsion [NE, 6% EO (w/w)], and its insecticidal properties evaluated against larvae and adults of Tribolium castaneum, Tribolium confusum and Tenebrio molitor. Two NE concentrations (500 and 1000 ppm) were applied on stored wheat. Mortality was determined after 4, 8 and 16 h and 1, 2, 3, 4, 5, 6 and 7 days. RESULTS: The NE was toxic to larvae of T. castaneum and T. confusum, killing 93.9% and 98.9% at 1000 ppm after 7 days of exposure, respectively. Tenebrio molitor larvae were tolerant: only 18.9% were dead after 7 days of exposure on stored wheat treated with 1000 ppm NE. However, the NE exhibited high adulticidal activity leading to 85.2% mortality at 1000 ppm, 7 days post-exposure. The mortalities of T. confusum and T. castaneum adults were low (21.4% and 23.3% respectively) at 1000 ppm, 7 days post-exposure. CONCLUSIONS: A NE based on C. acaulis EO could be regarded as an efficacious green adulticide or larvicide, depending on the target insect species and its life stage, advancing and specifying the pest management strategies of the tested species in an eco-friendly way. © 2022 Society of Chemical Industry.

Antioxidant Properties of Ester Derivatives of Cinnamic and Hydroxycinnamic Acids in Nigella sativa and Extra-Virgin Olive Oils-Based Emulsions.

New hydrophobic derivatives of cinnamic and hydroxycinnamic (ferulic and cumaric) acids obtained by chemical esterification of the carboxylic group with C10 linear alcohol were studied to evaluate their antioxidant capacity toward the superoxide anion and hydrogen peroxide in physiological buffer and in extra-virgin olive oil (EVO) or Nigella sativa oils. Results showed that cumaric and ferulic acids have higher antioxidants activity against superoxide anion and hydrogen peroxide than the other compounds. Cumaric acid and its C10-ester derivative were selected to be incorporated into EVO or Nigella sativa oil-based emulsions. The prepared emulsions had a comparable particle size distribution (in the range of 3-4 µm) and physical stability at least up to three months. Nigella sativa oil-based emulsions loaded with cumaric acid or its C10-ester showed a higher capacity to scavenger superoxide anion and hydrogen peroxide than EVO oil-based emulsions. In conclusion, cumaric acid or its C10-ester could promote the antioxidant properties of Nigella sativa oil when formulated as emulsions.

Factors affecting the rheological behaviour of carbomer dispersions in hydroalcoholic medium: Towards the optimization of hand sanitiser gel formulations.

Hand sanitizers represent a primary measure for the prevention of transmissible infections, whose use has been greatly increased during CoViD-19 pandemic. Most of the commercially available products are hydrogels, employing carbomers as thickening agents. However, few information is still available regarding performances of carbomers in hydroalcoholic media containing a percentage of alcohols ≥ 60% v/v as recommended for disinfection. The aim of this study was to investigate the colloidal behaviour of carbomer 974 and carbomer 980 in hydroalcoholic media containing from 50 to 80% w/w of alcohol (ethanol or isopropanol) and neutralised with triethanolamine or aminomethyl propanol. Both carbomers provide transparent hydrogels in water, but carbomer 980 should be preferred for the formulation of hydrogel with a percentage of alcohol ≥ 50% w/w for its better solvation. The critical alcohol concentration (CAlC), above which polymer precipitation occurs, depends on the type of alcohol and base used. Carbomer dispersions with a higher content of alcohol can be prepared using aminomethyl propanol rather than triethanolamine. The choice of the more suitable components is fundamental for the isopropanol-based dispersions since the CAlC is closer to the recommended concentrations for disinfection. Overall, these results provide helpful insights for the correct preparation of alcohol-based hand sanitizers using carbomers.

Development and characterization of monoterpene loaded microemulsions as novel scolicidal agents.

Cystic echinococcosis (CE) is one of the most important zoonotic diseases. The primary treatment is surgery and chemical sterilization of the parasitic layers by injection of a scolicidal agent. Available scolicidals possess side effects, and may cause postoperative complications. Several studies reported the scolicidal properties of monoterpene phenols and alcohols such as carvacrol, thymol, and geraniol. The present study aimed to develop, characterize, and assess monoterpene loaded microemulsions as novel green scolicidals products. For this purpose, microemulsions composing 0.37%, 0.75%, and 1.5% of monoterpenoid(s), thymol, carvacrol, and geraniol, alone or in binary or ternary mixtures were formulated. Samples were analyzed by visual inspection, polarizing optical microscope, and dynamic light scattering (DLS). The stability of the samples was evaluated up to a 3-month storage. For the scolicidal bioassay, samples at different concentrations of 200, 100, 50, 25, and 10 µg/ml were added to wells containing 104 viable protoscoleces and mortality rates were recorded at 2, 5, 10, and 20 min after exposure. Results of the present study showed that microemulsions formulated with 0.75% of pure carvacrol or the binary mixture of thymol and carvacrol at 0.375% are promising scolicidal agents.