Olive oil based novel thermo-reversible emulsion hydrogels for controlled delivery applications

Formulation and Characterization of Emulgel-Based Jelly Candy: A Preliminary Study on Nutraceutical Delivery

The development of consumer-friendly nutraceutical dosage forms is highly important for greater acceptance. In this work, such dosage forms were prepared based on structured emulsions (emulgels), where the olive oil phase was filled within the pectin-based jelly candy. The emulgel-based candies were designed as bi-modal carriers, where oil-soluble curcumin and water-soluble riboflavin were incorporated as the model nutraceuticals. Initially, emulsions were prepared by homogenizing varied concentrations (10% to 30% (w/w)) of olive oil in a 5% (w/w) pectin solution that contained sucrose and citric acid. Herein, pectin acted as a structuring agent-cum-stabilizer. Physico-chemical properties of the developed formulations were thoroughly analyzed. These studies revealed that olive oil interferes with the formation of polymer networks of pectin and the crystallization properties of sugar in candies. This was confirmed by performing FTIR spectroscopy and DSC studies. In vitro disintegration studies showed an insignificant difference in the disintegration behavior of candies, although olive oil concentration was varied. Riboflavin and curcumin were then incorporated into the jelly candy formulations to analyze whether the developed formulations could deliver both hydrophilic and hydrophobic nutraceutical agents. We found that the developed jelly candy formulations were capable of delivering both types of nutraceutical agents. The outcome of the present study may open new directions for designing and developing oral nutraceutical dosage forms.

Encapsulation of Zataria multiflora essential oil in polyvinyl alcohol/chitosan/gelatin thermo-responsive hydrogel: Synthesis, physico-chemical properties, and biological investigations

Zataria multiflora essential oil is a natural volatile plant product whose therapeutic applications require a delivery platform. Biomaterial-based hydrogels have been extensively used in biomedical applications, and they are promising platforms to encapsulate essential oils. Among different hydrogels, intelligent hydrogels have recently attracted many interests because of their response to environmental stimuli such as temperature. Herein, Zataria multiflora essential oil is encapsulated in a polyvinyl alcohol/chitosan/gelatin hydrogel as a positive thermo-responsive and antifungal platform. According to the optical microscopic image, the encapsulated spherical essential oil droplets reveal a mean size of 1.10 ± 0.64 μm, which are in consistent with the SEM imaging results. Encapsulation efficacy and loading capacity are 98.66 % and 12.98 %, respectively. These results confirm the successful efficient encapsulation of the Zataria multiflora essential oil within the hydrogel. The chemical compositions of the Zataria multiflora essential oil and the fabricated hydrogel are analyzed by gas chromatography-mass spectroscopy (GC-MS) and Fourier transform infrared (FTIR) techniques. It is found that thymol (44.30 %) and γ-terpinene (22.62 %) are the main constituents of the Zataria multiflora essential oil. The produced hydrogel inhibits the metabolic activity of Candida albicans biofilms (~60-80 %), which can be related to the antifungal activity of the essential oil constituents and chitosan. Based on the rheological results, the produced thermo-responsive hydrogel shows a gel-sol viscoelastic transition at a temperature of 24.5 °C. This transition leads to a facile release of the loaded essential oil. The release test depicts that about 30 % of Zataria multiflora essential oil is released during the first 16 min. In addition, 2, 5-diphenyl-2H-tetrazolium bromide (MTT) assay demonstrates that the designed thermo-sensitive formulation is biocompatible with high cell viability (over 96 %). The fabricated hydrogel can be deemed as a potential intelligent drug delivery platform for controlling cutaneous candidiasis due to antifungal effectiveness and less toxicity, which can be a promising alternative to traditional drug delivery systems.

Novel Formulation of Bigel-Based Vegetable Oil Spreads Enriched with Lingonberry Pomace

In this study, bigel-based vegetable oil spreads with lingonberry pomace addition were prepared. The impact of gelatin, agar and collagen was examined as structuring agents as was the effect of lecithin concentration (0.5, 1.0, 1.5%). Prepared systems were evaluated by physical and chemical stability and structural and rheological properties. It was found that all bigel formulations were self-standing with no signs of phase separation at ambient temperature immediately after preparation and after two weeks of storage at 4 °C temperature. The lingonberry pomace addition affected grainy structure formation with homogenous and uniform distribution of fiber particles throughout the bigel matrix and it also altered the colour of the bigels toward a purple-red. Texture, rheological properties and colour of the spread formulations were affected by the type of the structuring agent as well as the lecithin concentration. The presence of the lingonberry pomace enhanced the resistance of the bigel samples to the oxidation process and it was confirmed by the DPPH^• inhibition, peroxide value and oxipress test. Overall, the formulated bigel-based spreads could be beneficial and had a potential application as healthier fat spreads and be a source of dietary fibers (11 g of fibre per 100 g of the spread).

Long-Acting Formulations: A Promising Approach for the Treatment of Chronic Diseases

Medication and patient adherence are the two main aspects of any successful treatment of chronic disease. Even though diseases and its treatment existed for several hundred years, the treatment optimization for a given patient is still a researcher question for scientists. There are differences in treatment duration, prognostic signs and symptoms between patient to patient. Hence, designing ideal formulation to suit individual patient is a challenging task. The conventional formulations like oral solids and liquids gives a partial or incomplete treatment because the patient needs to follow the daily pills for a longer time. In such cases, the long-acting formulations will have better patient compliances as drug will be released for a longer duration. Many such approaches are under the clinical investigation. The favorable pharmacokinetic and pharmacodynamic relationships, will be promising option for the treatment of chronic diseases. In this review, we have highlighted the importance of long-acting formulations in the treatment of chronic diseases and the advent of newer formulation technologies.

Update on the Medical and Surgical Management of Urethral Condyloma

INTRODUCTION

Condyloma acuminata (CA) of the urethra presents a management challenge due to high recurrence rates, difficulty in accessing urethral lesions, risk of stricture formation, and potential for sexual dysfunction. While standard treatment modalities are acceptable for some external genital condyloma, they are not always feasible or appropriate for urethral lesions.

OBJECTIVES

We sought to review the literature on epidemiology, presentation, diagnosis and treatment of urothelial CA with a focus on surgical treatment options.

METHODS

We performed a comprehensive literature search of PubMed to identify all studies pertaining to urethral CA through November 2020.

RESULTS

Urethral CA is a relatively rare, but challenging disease to manage with a considerable amount of treatment side effects and downstream morbidity associated. In our comprehensive review we have found a wide selection of treatment modalities ranging from minimally invasive strategies to surgical reconstructive techniques. Proper follow-up to monitor for disease recurrence at the 3-4 month mark is appropriate and will determine subsequent treatment strategies as needed. Future studies and treatment directions include novel drug delivery models to optimize minimally invasive topical drug efficacy.

CONCLUSION

Treatment of urethral CA should be approached in a step-wise fashion. Medical therapy would be an appropriate option for asymptomatic or minimally symptomatic patients with small lesions who desire to avoid any interventions. If patient is symptomatic, has extensive disease burden or has failed medical therapy intervention should be considered with options including PDT, laser ablation or surgical excision with or without urethral reconstruction. Appropriate selection depends on patient characteristics and preferences along with prior treatment history. Kim CJ, Campbell SP, Allkanjari A, et al. Update on the Medical and Surgical Management of Urethral Condyloma. Sex Med Rev 2021;xxx:xxx-xxx.

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.

Novel oleogel formulation based on amaranth oil: Physicochemical characterization

This study aims to investigate the characteristics of oleogel (OG) produced from amaranth oil at four concentrations of 7%, 9%, 10%, and 12% of the monoglyceride (MG). The physicochemical and structural aspects were performed by using pulsed nuclear magnetic resonance, differential scanning calorimetry, X-ray diffraction, and gas chromatography. The results show that oleogels (OGs) had higher oxidative stability during storage at ambient temperature in comparison with amaranth oil. Moreover, polarized optical microscopy revealed that an increase in percentage of the oleogelator leads to the formation of needle-shaped crystals followed by oil entrapment. Also, MG improves the solid content of amaranth oil from 0.5% to 11% and creates a solid structure in spite of the low solid fat as compared to cocoa butter (CB) (82%), as control sample. Crystals similar to CB were also observed when evaluating the crystalline structure of the OG. The fatty acid ratio and the essential linoleic fatty acid were preserved in the OG by only 2%-6% reduction.

Amphiphilic bromelain-synthesized oligo-phenylalanine grafted with methoxypolyethylene glycol possessing stabilizing thermo-responsive emulsion properties

A thermo-responsive amphiphile was developed from oligo-phenylalanine [oligo(Phe)]. The hydrophobic moiety of the amphiphile, oligo(Phe) was synthesized via reverse hydrolysis catalyzed by bromelain in dimethyl sulfoxide and dioxane solutions. The production of oligo(Phe) increased by 80.7% by screening suitable reaction conditions. The average degree of polymerization of oligo(Phe) was determined to be four by ¹H NMR. By grafting with aldehyde-ended methoxypolyethylene glycol (mPEG), oligo(Phe) was converted to amphiphilic oligo(Phe)-mPEG. The surface tension of oligo(Phe)-mPEG solution increased with decreasing chain length of the mPEG moiety. Cytotoxicity studies showed oligo(Phe)-mPEGs are biocompatible. On varying temperature, a reversible phase transition of oligo(Phe)-mPEG solutions could be observed. N-octane-in-water emulsions and 0.5% beta-carotene containing squalene-in-water emulsions stabilized by oligo(Phe)-mPEGs occurred at 25 °C but de-emulsification took place at >40 °C. Emulsification could be restored once the separated mixture cooled and re-homogenized. The emulsification/de-emulsification cycling could be repeated many times. The time required for de-emulsification decreased with elevated temperature but increased with a reduced concentration of oligo(Phe)-mPEGs and a reduction in the chain length of the mPEG moiety.

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.

Methyl Methacrylate HIPE Solely Stabilized by Fluorinated Di-block Copolymer for Fabrication of Highly Porous and Interconnected Polymer Monoliths

Preparation of stable water-in-oil (W/O) high internal phase emulsion (HIPE) containing methyl methacrylate (MMA) monomer as oil phase is a difficult task due to the significant solubility of MMA in water. Here, for the first time a fluorinated di-block copolymer (FDBC) poly (2-dimethylamino)ethylmethacrylate-b-poly (trifluoroethyl methacrylate) (PDMAEMA-b-PTFEMA) is proposed to stabilize HIPEs of MMA without the use of any co-stabilizer or thickening agent. Fluorinated segments in FDBC anchored well at oil/water interface of HIPE, offering high hydrophobicity to the partially hydrophilic MMA monomer and in turn stabilization to MMA-HIPE. By using fluorinated di-block copolymer as stabilizer, highly stable HIPEs can be obtained. In addition, highly interconnected porous monoliths were obtained after free radical polymerization, which are highly desirable materials in various practical applications including tissue engineering scaffolds, separation science, bio-engineering and so on. The as-prepared MMA-HIPEs possess high thermal stability without phase separation. The textural characteristics of as-prepared composites, such as pore size and distribution, can be easily controlled by simply varying the amount of FDBC and/or dispersed phase fraction. Moreover, the influence of di-block concentration on water uptake (WU) capability of the prepared porous monoliths is explored.

Genipin-Crosslinked Gelatin-Based Emulgels: an Insight into the Thermal, Mechanical, and Electrical Studies

The present study discusses about the preparation and characterization (thermal, mechanical, and electrical) of the genipin-crosslinked gelatin emulgels. Emulgels have gained importance in recent years due to their improved stability than emulsions and ability to control the drug release. Mustard oil was used as the representative oil. A decrease in the enthalpy and entropy of the formulations was observed with the increase in the oil fraction. The mechanical studies suggested formation of softer emulgels as the oil fraction was increased. As the proportion of the oil fraction was increased in the emulgels, there was a corresponding increase in the impedance. The drug release properties from the emulgels were also studied. Ciprofloxacin was used as the model antimicrobial drug. The drug release was higher from the emulgels whose electrical conductivity was higher.

Olive oil and hyperthermal water bigels for cosmetic uses

Bigels are biphasic systems produced with an organogel (or oleogel) and a hydrogel mixed together at high shear rates. These systems are promising for different uses, among them the formulation of new cosmetic matrices for cosmetic agents delivery is under investigation. In the present paper, a common cosmetic formulation for skin care was enriched with increasing fractions of monoglycerides of fatty acids/olive oil organogels, in order to understand the rheology and the microstructure of these systems. Small amplitude oscillation tests, NMR-self diffusion analysis, contrast phase microscopy and electric conductivity confirmed that the addition of the organogel caused a microstructural change of the starting material, which turned from O/W to a more complex system where, probably, a matrix-in-matrix structure is present at the highest fractions of added organogel.

Development and characterization of sorbitan monostearate and sesame oil-based organogels for topical delivery of antimicrobials

The current study explains the development of sorbitan monostearate and sesame oil-based organogels for topical drug delivery. The organogels were prepared by dissolving sorbitan monostearate in sesame oil (70°C). Metronidazole was used as a model antimicrobial. The formulations were characterized using phase contrast microscopy, infrared spectroscopy, viscosity, mechanical test, and differential scanning calorimetry. Phase contrast microscopy showed the presence of needle-shaped crystals in the organogel matrix. The length of the crystals increased with the increase in the sorbitan monostearate concentration. XRD studies confirmed the amorphous nature of the organogels. Viscosity study demonstrated shear thinning behavior of the organogels. The viscosity and the mechanical properties of the organogels increased linearly with the increase in the sorbitan monostearate concentration. Stress relaxation study confirmed the viscoelastic nature of the organogels. The organogels were biocompatible. Metronidazole-loaded organogels were examined for their controlled release applications. The release of the drug followed zero-order release kinetics. The drug-loaded organogels showed almost similar antimicrobial activity against Escherichia coli when compared to the commercially available Metrogyl® gel. In gist, it can be proposed that the developed organogels had sufficient properties to be used for controlled delivery of drugs.

Development of soy lecithin based novel self-assembled emulsion hydrogels

The current study reports the development and characterization of soy lecithin based novel self-assembled emulsion hydrogels. Sesame oil was used as the representative oil phase. Emulsion gels were formed when the concentration of soy lecithin was >40% w/w. Metronidazole was used as the model drug for the drug release and the antimicrobial tests. Microscopic study showed the apolar dispersed phase in an aqueous continuum phase, suggesting the formation of emulsion hydrogels. FTIR study indicated the formation of intermolecular hydrogen bonding, whereas, the XRD study indicated predominantly amorphous nature of the emulsion gels. Composition dependent mechanical and drug release properties of the emulsion gels were observed. In-depth analyses of the mechanical studies were done using Ostwald-de Waele power-law, Kohlrausch and Weichert models, whereas, the drug release profiles were modeled using Korsmeyer-Peppas and Peppas-Sahlin models. The mechanical analyses indicated viscoelastic nature of the emulsion gels. The release of the drug from the emulsion gels was diffusion mediated. The drug loaded emulsion gels showed good antimicrobial activity. The biocompatibility test using HaCaT cells (human keratinocytes) suggested biocompatibility of the emulsion gels.

Characterization of gelatin-agar based phase separated hydrogel, emulgel and bigel: a comparative study

The current study describes the in-depth characterization of agar-gelatin based co-hydrogels, emulgels and bigels to have an insight about the differences in the properties of the formulations. Hydrogels have been extensively studied as vehicle for controlled drug release, whereas, the concept of emulgels and bigels is relatively new. The formulations were characterized by scanning electron microscopy, FTIR spectroscopy, XRD and mechanical properties. The biocompatibility and the ability of the formulations to be used as drug delivery vehicle were also studied. The scanning electron micrographs suggested the presence of internal phases within the agar-gelatin composite matrices of co-hydrogel, emulgel and bigel. FTIR and XRD studies suggested higher crystallinity of emulgels and bigels. Electrical impedance and mechanical stability of the emulgel and the bigel was higher than the hydrogel. The prepared formulations were found to be biocompatible and suitable for drug delivery applications.

Guar gum and sesame oil based novel bigels for controlled drug delivery

Bigels are novel semi-solid formulations which have been drawing attention of many research scientists due to their numerous advantages over the conventional gels. The objective of this study was to develop and characterize novel bigels by mixing guar gum hydrogel and sorbitan monostearate-sesame oil based organogel for controlled drug delivery applications. The confocal microscopy suggested the existence of both aqueous and oil phases together as bigel. Micro-scale deformation (viscometric) analysis in conjugation with macro-scale deformation studies suggested shear-thinning and viscoelastic nature of the bigels. Thermal study suggested an increase in thermal stability with the increase in organogel proportion in the bigels. The developed bigels were biocompatible in nature. The in vitro drug release study showed that the release of ciprofloxacin (lipophilic drug) increased with a decrease in the organogel content. Further analysis showed that the drug release from all the bigels followed zero order diffusion kinetics which is desirable for a controlled release system. The drug loaded gels showed good antimicrobial efficiency against Bacillus subtilis. In conclusion, the developed bigels may be tried as matrices for topical drug delivery.

Preparation and characterization of novel carbopol based bigels for topical delivery of metronidazole for the treatment of bacterial vaginosis

The current study reports the development of bigels using sorbitan monostearate-sesame oil organogel and carbopol 934 hydrogel. The microstructures and physicochemical properties were investigated by microscopy, viscosity measurement, mechanical analysis and differential scanning calorimetry analysis. Fluorescence microscopy confirmed the formation of oil-in-water type of emulsion gel. There was an increase in the strength of the bigels as the proportion of the organogel was increased in the bigels. The developed bigels showed shear-thinning flow behavior. The stress relaxation study suggested viscoelastic nature of the bigels. The developed bigels were biocompatible. Metronidazole, drug of choice for the treatment of bacterial vaginosis, loaded bigels showed diffusion-mediated drug release. The drug loaded gels showed good antimicrobial efficiency against Escherichia coli. In gist, the developed bigels may be used as delivery vehicles for the vaginal delivery of the drugs.