Semi-solid Gel Research Articles

Ketoconazole-conjugated ZnO nanoparticles based semi-solid formulation and study their impacts on skin disease.

In this study, the ketoconazole-conjugated zinc oxide (ZnO) nanoparticles were prepared in a single-step approach using dextrose as an intermediate compound. The physical parameters confirmed the drug conjugation with ZnO and their size was around 70-75 nm. The drug loading and in vivo drug release studies indicated that the -CHO group from the dextrose increase the drug loading up to 65% and their release kinetics were also studied. The anti-fungal studies indicated that the prepared nanoparticles exhibit strong anti-fungal activity and the minimum concentration needed is 10 mg/ml. The nanoparticles loaded semi-solid gel was prepared using carbopol, methylparaben, propyl paraben and propylene glycol. The in vitro penetration of the ketoconazole-conjugated nanoparticles was studied using the skin. The results indicated that the semi-solid gel preparations influenced the penetration and also favoured the accumulation into the skin membrane. The veterinary clinical studies indicated that the prepared gel is highly suitable for treatment of Malassezia.

Application of thermoreversible hydrogel (poloxamer 407) to protect the corneal endothelium during phacoemulsification in porcine and rabbit eyes

To evaluate the effectiveness of thermoreversible (poloxamer) hydrogels as a substitute for ophthalmic viscosurgical devices (OVDs) during phacoemulsification in porcine and rabbit eyes and compare their endothelial protective effect with that of hyaluronic acid-based OVDs. Department of Ophthalmology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, South Korea. Experimental study. Fluorescein-stained poloxamer hydrogels (20%, 22%, 24%, and 26% [weight/weight%]) and cohesive (sodium hyaluronate 1.0% [Provisc]) and dispersive (sodium hyaluronate 3.0%-chondroitin sulfate 4.0% [Viscoat]) OVDs were injected into the anterior chamber of porcine eyes incubated at 32°C. In the invitro study, the retention time was measured in 3 groups of 45 porcine eyes during continuous phacoemulsification. In the invivo study, the endothelial cell count (ECC) was measured before and 3days after intermittent phacoemulsification in 12 rabbit eyes randomized to a poloxamer hydrogel or a dispersive OVD group. The optimum concentration of thermosensitive hydrogel was 26%, at which no gel-to-sol phase transition occurred in the anterior chamber, with a 21°C irrigation solution. In the invitro study, the mean retention times were 5.53seconds±1.77 (SD), 125.00±29.34seconds, and 221.53±42.48seconds in the cohesive OVD, dispersive OVD, and 26% poloxamer hydrogel groups, respectively (P<.001). Throughout the 5-minute intermittent phacoemulsification, the 26% poloxamer hydrogel remained in the anterior chamber as a semisolid gel. In the invivo study, the mean decrease in ECC was significantly lower in the 26% poloxamer hydrogel group than in the dispersive OVD group (P=.029). Thermoreversible hydrogels might be suitable substitutes for hyaluronic acid-based OVDs for corneal endothelial protection during phacoemulsification.

Thiol-maleimide poly(ethylene glycol) crosslinking of L-asparaginase subunits at recombinant cysteine residues introduced by mutagenesis

L-Asparaginase is an enzyme successfully being used in the treatment of acute lymphoblastic leukemia, acute myeloid leukemia, and non-Hodgkin’s lymphoma. However, some disadvantages still limit its full application potential, e.g., allergic reactions, pancreatitis, and blood clotting impairment. Therefore, much effort has been directed at improving its performance. A popular strategy is to randomly conjugate L-asparaginase with mono-methoxy polyethylene glycol, which became a commercial FDA approved formulation widely used in recent years. To improve this formulation by PEGylation, herein we performed cysteine-directed conjugation of the L-asparaginase subunits to prevent dissociation-induced loss of activity. The recombinant cysteine conjugation sites were introduced by mutagenesis at surface-exposed positions on the protein to avoid affecting the catalytic activity. Three conjugates were obtained using different linear PEGs of 1000, 2000, and 5000 g/mol, with physical properties ranging from a semi-solid gel to a fully soluble state. The soluble-conjugate exhibited higher catalytic activity than the non-conjugated mutant, and the same activity than the native enzyme. The cysteine-directed crosslinking of the L-asparaginase subunits produced a higher molecular weight conjugate compared to the native tetrameric enzyme. This strategy might improve L-asparaginase efficiency for leukemia treatment by reducing glomerular filtration due to the increase in hydrodynamic size thus extending half-live, while at the same time retaining full catalytic activity.

Risk of asphyxiation from Vernagel ingestion.

Vernagel (sodium polyacrylate) is a powder commonly used in hospitals worldwide for the management and disposal of body fluids. It reacts with fluids to form a semisolid gel. Its main use is to reduce spillages. If ingested, this substance presents significant risk of asphyxiation. There have been 15 reported cases of Vernagel ingestion in 6 years and 1 death from asphyxiation. We present the case of an elderly patient who was admitted following a fall. He accidentally ingested a sachet of Vernagel during the early hours of the morning. An urgent rigid panendoscopy was performed and the material was evacuated using suction aspiration. Patients should be supervised when using Vernagel on the ward, to avoid ingestion. Ear, nose and throat doctors should be aware of Vernagel and its properties. Owing to the risk of airway obstruction, excellent coordination between the anaesthetist and surgeon is crucial, and prompt management is required.

Development of a Vaginal Fast-Dissolving Insert Combining Griffithsin and Carrageenan for Potential Use Against Sexually Transmitted Infections

Precoital, on-demand topical microbicides to reduce a woman's risk of sexually transmitted infections have been in development for nearly 3 decades, but no product has been approved due to acceptability issues and poor adherence in clinical trials. We set out to develop a self-administered vaginal fast-dissolving insert (FDI) produced by freeze-drying that would deliver safe and effective amounts of the antiviral agents griffithsin (GRFT) and carrageenan (CG) and would have properties women and their partners find acceptable. We evaluated FDI physical criteria, attributes of the gel produced upon dissolving, and GRFT stability. The lead formulation, FDI-024, was selected from 13 candidates and contains 4 mg of GRFT, 15 mg of CG, and excipients (the cryoprotectant sucrose and bulking agents dextran 40 and mannitol). The FDI exhibits good friability and hardness and is stable for at least 6 months at up to 40°C/75% relative humidity. It disintegrates in less than 60 s in a physiologically relevant volume (∼1 mL) of simulated vaginal fluid, forming a viscous semi-solid gel with favorable mucoadhesive and spreading properties. The formulation retains the antiviral activity of GRFT and CG against HIV type 1 and human papillomavirus, respectively, in cell-based assays.

Effect of mechanical contrast on sensory perception of heterogeneous liquid and semi-solid foods

This study investigated the influence of size and fracture stress (σF) of dispersed particles embedded in liquid and semi-solid model food matrices on sensory perception and hedonic response. К-carrageenan particles varying in size (0.8, 2.4, 4.2 mm) and fracture stress (σF: 25, 100, 250 kPa) were added (15% w/w) to liquid starch-based model soups and semi-solid protein-based model gels. Sensory profiles were quantified by untrained panellists (n = 54) using the Rate-All-That-Apply (RATA) method. Particle size mainly affected the type of sensory descriptors selected by the subjects, whereas fracture stress of particles determined mainly the perceived intensity of selected descriptors. Soups and gels with small particles (0.8 mm) were mainly perceived as gritty, whereas soups and gels with medium-sized particles (2.4 mm) were mainly perceived as beady. Increasing particle size to 4.2 mm caused lumpy and heterogeneous sensations in soups and gels. With variations of particle fracture stress, the perceived intensity of the selected attributes increased or decreased significantly for all particle sizes. Mouthfeel heterogeneity and chewiness increased significantly when increasing the fracture stress from 20 to 100 or 250 kPa. Mechanical contrast did not enhance liking of model soups and gels probably because к-carrageenan particles were perceived as artificial and provided texture contrast without flavour contrast. We conclude that size and fracture stress of dispersed particles embedded in liquid and semi-solid model food matrices affect differently sensory perception with particle size determining type of sensory descriptors selected and particle fracture stress determining intensity of selected sensory attributes.

The influence of sodium and sulfate ions on total solidification and encapsulation potential of iron-rich acid mine drainage in silica gel

Upon neutralization by acid mine drainage (AMD) a semi-solid silica gel forms from sodium silicate. During the solidification of silica gel, the surrounding positively charged toxic heavy metals can also be adjoined to the negatively charged silica network in a similar manner by forming a newly metal–silica bond. Simultaneously, sodium silicate addition increases the pH value of the AMD and restricts the solubility and leachability of the most metal ions. Thus, this experimental study investigated the adjoining potential of the metal ions (particularly iron) into the silica gel at different acidic-alkaline conditions (pH: 5.5, 7, and 9) in the presence of excessive Na+ and SO4−2 ions originated from sodium silicate solution and AMD respectively. As described via infrared spectroscopy (FTIR), X-ray diffractometry (XRD), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), and thermogravimetric (TGA) analyses, the extended gelation time at pH 5.5 and 9 resulted in a higher precipitation of secondary minerals such as sodium and iron sulfates while the only formed encapsulant mineral, sodium iron silicon oxide was constantly formed at any pH value. The acid leaching of solid AMD specimens up to 96 hours resulted in 7 to16% iron ions release that can be attributed to the dissolution of secondary formed iron-based minerals.

Effect of the Dispersion States of Azone in Hydroalcoholic Gels on Its Transdermal Permeation Enhancement Efficacy

The objective of this study was to investigate the effect of dispersion states of azone in gels on the transdermal permeation of levamisole hydrochloride (LH). LH hydroalcoholic gels containing azone of different dispersion states were prepared by varying the contents of azone and Tween 80, and the in vitro transdermal permeation of LH across excised rat skin was evaluated. Depending on the content of azone, mixed solvents, and solubilizer used, azone presented as dissolved molecules, solubilized in micelles, and fine or coarse emulsion droplets in gels. Dramatically increased transdermal permeation of LH within the azone contents between 0.25% and 0.75% indicated high transdermal enhancement efficiency of the molecular or micellar azone, and extra azone that existed as oil droplets did not fully exert transdermal penetration enhancement of LH. Although solubilizer (Tween 80) can greatly increase the solubility of azone, only small amount of Tween 80 (0.5%) in the gel significantly increased the steady-state flux of LH. Addition of extra amount of Tween 80 (>0.5%) reduced the amount of azone distributed in the skin, and thus decreased the transdermal drug permeation. The results partly elucidated the versatile effects of the dispersion states of azone on the transdermal permeation of hydrophilic drug from semisolid gels.

Enhancement of Dissolution and Skin Permeability of Pentazocine by Proniosomes and Niosomal Gel.

Proniosomes (PN) are the dry water-soluble carrier systems that may enhance the oral bioavailability, stability, and topical permeability of therapeutic agents. The low solubility and low oral bioavailability due to extensive first pass metabolism make Pentazocine as an ideal candidate for oral and topical sustained release delivery. The present study was aimed to formulate the PNs by quick slurry method that are converted to niosomes (liquid dispersion) by hydration, and subsequently formulated to semisolid niosomal gel. The PNs were found in spherical shape in the SEM and stable in the physicochemical and thermal analysis (FTIR, TGA, and XRD). The quick slurry method produced high recovery (> 80% yield) and better flow properties (θ = 28.1-37.4°). After hydration, the niosomes exhibited desirable entrapment efficiency (44.45-76.23%), size (4.98-21.3μm), and zeta potential (- 9.81 to - 21.53mV). The in vitro drug release (T100%) was extended to more than three half-lives (2-4h) and showed good fit to Fickian diffusion indicated by Korsmeyer-Peppas model (n = 0.136-0.365 and R2 = 0.9747-0.9954). The permeation of niosomal gel was significantly enhanced across rabbit skin compared to the pure drug-derived gel. Therefore, the PNs are found promising candidates for oral as dissolution enhancement and sustained release for oral and topical delivery of pentazocine for the management of cancer pain.

In-line UV spectroscopy for the quantification of low-dose active ingredients during the manufacturing of pharmaceutical semi-solid and liquid formulations

UltraViolet (UV) spectroscopy was evaluated as an innovative Process Analytical Technology (PAT) - tool for the in-line and real-time quantitative determination of low-dosed active pharmaceutical ingredients (APIs) in a semi-solid (gel) and a liquid (suspension) pharmaceutical formulation during their batch production process. The performance of this new PAT-tool (i.e., UV spectroscopy) was compared with an already more established PAT-method based on Raman spectroscopy. In-line UV measurements were carried out with an immersion probe while for the Raman measurements a non-contact PhAT probe was used. For both studied formulations, an in-line API quantification model was developed and validated per spectroscopic technique. The known API concentrations (Y) were correlated with the corresponding in-line collected preprocessed spectra (X) through a Partial Least Squares (PLS) regression. Each developed quantification method was validated by calculating the accuracy profile on the basis of the validation experiments. Furthermore, the measurement uncertainty was determined based on the data generated for the determination of the accuracy profiles. From the accuracy profile of the UV- and Raman-based quantification method for the gel, it was concluded that at the target API concentration of 2% (w/w), 95 out of 100 future routine measurements given by the Raman method will not deviate more than 10% (relative error) from the true API concentration, whereas for the UV method the acceptance limits of 10% were exceeded. For the liquid formulation, the Raman method was not able to quantify the API in the low-dosed suspension (0.09% (w/w) API). In contrast, the in-line UV method was able to adequately quantify the API in the suspension. This study demonstrated that UV spectroscopy can be adopted as a novel in-line PAT-technique for low-dose quantification purposes in pharmaceutical processes. Important is that none of the two spectroscopic techniques was superior to the other for both formulations: the Raman method was more accurate in quantifying the API in the gel (2% (w/w) API), while the UV method performed better for API quantification in the suspension (0.09% (w/w) API).

ANTI-ACNE GEL OF ISOTRETINOIN: FORMULATION AND EVALUATION

Objective: Isotretinoin is a very effective drug in the treatment of acne vulgaris by topically. The objective of present study was formulation development of anti-acne gel using Isotretinoine and span 80 for topical delivery to cure nodulosystic acne vulgaris. Furthermore, the comparative study of all the evaluation parameters done with marketed formulation of same drug.Methods: Formulation of anti-acne gel of isotretinoin using Carbopol 940 as a polymer and incorporating isotretinoin in form of topical semi-solid gel using magnetic stirrer, Cremophor RH 40, and butylated hydroxytoluene. Drug was uniformly dispersed in Cremophor RH 40 and the respected solvents. Ethanol, isopropyl alcohol, and glycerin were used as solvents in 15% quantity. Further, the formulation was evaluated for physicochemical evaluation of gel formulations. The prepared gel were optimized statistically and characterized for pH, spredability, drug content, viscosity, in vitro diffusion study, acute skin irritation test, and antimicrobial activity. Evaluation test was also compared with marketed formulation of isotretinoin, that is, Sortet gel. The antibacterial and anti-acne activity of different formulations was determined by modified agar well diffusion method on the culture of Propionibacterium acne also compared with marketed formulation.Results: The optimized batch (B10) showed highest spreadability (32.422 g/cm3) in all formulations and also have high percentage of drug contents (95.60%). The spreadability value was 17.998 g/cm3 showing good spreadability. The viscosity of optimized batch was observed less as compared to other formulations, ultimately showed releases also more. In the in vitro diffusion study, B10 batch release 85.69% of the drug as compared to Sotret gel. The antibacterial activity was studied on anaerobic microorganism P. acne, compared with marketed Sortet gel. Optimized batch showed maximum zone of inhibition to P. acne below marketed formulations and standard benzyl peroxide gel.Conclusion: The topical anti-acne gel of isotertinoin was successfully formulated and evaluated for different parameters. The results indicate that the active component, that is, isotertinoin is more effective when subjected in gel formulations and produces effective anti-acne activity in the management of nodulosystic acne vulgaris.

A novel vehicle for local protein delivery to the inner ear: injectable and biodegradable thermosensitive hydrogel loaded with PLGA nanoparticles

Delivery of biomacromolecular drugs into the inner ear is challenging, mainly because of their inherent instability as well as physiological and anatomical barriers. Therefore, protein-friendly, hydrogel-based delivery systems following local administration are being developed for inner ear therapy. Herein, biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) containing interferon α-2 b (IFN α-2 b) were loaded in chitosan/glycerophosphate (CS/GP)-based thermosensitive hydrogel for IFN delivery by intratympanic injection. The injectable hydrogel possessed a physiological pH and formed semi-solid gel at 37 °C, with good swelling and deswelling properties. The CS/GP hydrogel could slowly degrade as visualized by scanning electron microscopy (SEM). The presence of NPs in CS/GP gel largely influenced in vitro drug release. In the guinea pig cochlea, a 1.5- to 3-fold increase in the drug exposure time of NPs-CS/GP was found than those of the solution, NPs and IFN-loaded hydrogel. Most importantly, a prolonged residence time was attained without obvious histological changes in the inner ear. This biodegradable, injectable, and thermosensitive NPs-CS/GP system may allow longer delivery of protein drugs to the inner ear, thus may be a potential novel vehicle for inner ear therapy.

Investigating the Water Sealing Capability of Polymer Concrete

The concrete water sealing capability improved substantially by using superabsorbent polymer as admixture in the concrete mix design. Researchers tried almost every conceivable material to be mixed in concrete to alter some of its properties. In this research, superabsorbent polymer is used as an admixture to improve its water tightness properties especially in concrete tanks, aeration basins and retaining structures. The concrete tries to seal the leak by blocking the water path by semi-solid gels. This gel is the product of the interaction of the superabsorbent polymer with water. This self-sealing property of concrete can also be used in any tank or container that holds and retains any kind of liquid. The super absorbent polymer absorbs water at a rate of 300 to 500 times its own weight, in a process transforming the polymer dry powered into gel. Mixing super absorbent polymer with concrete not only improves its water tightness capability, but also provides the concrete with internal curing moisture it needs to improve its strength. This property is very useful in cases where curing of concrete is difficult. The fresh concrete plasticity and consistency change as well. This property is yet to be further explored. Several samples have been prepared to study the effect of the superabsorbent polymer on the concrete strength and on the concrete capability to block the water flow. Concrete cubes, concrete beams and concrete tension samples were prepared to study the concrete strength of concrete mixed with superabsorbent polymer. Also concrete short cylindrical samples were prepared to study the concrete ability to block the water flow. These cylindrical samples were intentionally broken into two approximately equal pieces to create an induced crack. The artificially cracked samples are then subjected to water pressure to study the concrete ability to stop the water flow though the induced concrete crack. Two kinds of water pressure are used in this research; the constant head and the falling head. Samples of different amount of superabsorbent polymer were prepared to study the effect of the increase of the superabsorbent polymer on the concrete strength and on the concrete water tightness capability.

Self-sealing concrete mortar, concrete mortar mixed with super absorbent polymer

Researchers tried almost every conceivable material to be mixed in concrete to alter some of its properties. In this research superabsorbent polymer is used as an admixture to improve its water tightness properties especially in concrete tanks, aeration basins, and retaining structures. The concrete tries to seal the leak by blocking the water path by semi-solid gels. This gel is the product of the interaction of the superabsorbent polymer with water. Several samples have been prepared to study the effect of the superabsorbent polymer on the concrete strength, and on the concrete capability to block the water flow. Concrete cubes, concrete beams, and concrete tension samples were prepared to study the concrete strength of concrete mixed with superabsorbent polymer. Also concrete short cylindrical samples were prepared to study the concrete ability to block the water flow. These cylindrical samples were intentionally broken into two approximately equal pieces to create an induced crack. The artificially cracked samples are then subjected to water pressure to study the concrete ability to stop the water flow though the induced concrete crack. Two kinds of water pressure are used in this research; the constant head, and the falling head.

Effect of Rheology and Poloxamers Properties on Release of Drugs from Silicon Dioxide Gel-Filled Hard Gelatin Capsules-A Further Enhancement of Viability of Liquid Semisolid Matrix Technology.

The liquid and semisolid matrix technology, filling liquids, semi-solids and gels in hard gelatin capsule are promising, thus, there is a need of enhanced research interest in the technology. Therefore, the present study was aimed to investigate isoniazid (freely soluble) and metronidazole (slightly soluble) gels filled in hard gelatin capsules for the effect of poloxamers of different viscosities on release of the drugs. Gel of each drug (10% w/w, particle size 180-250μm), prepared by mixing poloxamer and 8% w/w hydrophilic silicon dioxide (Aerosil® A200), was assessed for rheology, dispersion stability and release profile. Both the drugs remained dispersed in majority of gels for more than 30days, and dispersions were depended on gels' viscosity, which was further depended on viscosity of poloxamers. A small change in viscosity was noted in gels on storage. FTIR spectra indicated no interactions between components of the gels. The gels exhibited thixotropic and shear-thinning behaviour, which were suitable for filling in hard gelatin capsules without any leakage from the capsules. The release of both drugs from the phase-stable gels for 30days followed first-order kinetics and was found to be correlated to drugs' solubility, poloxamers' viscosity, polyoxyethylene contents and proportion of block copolymer (poloxamers) in the gels. The findings of the present study indicated that release of drugs of different solubilities (isoniazid and metronidazole) might be modified from gels using different poloxamers and Aerosil® A200.

Comparison of Dapivirine Vaginal Gel and Film Formulation Pharmacokinetics and Pharmacodynamics (FAME 02B).

While preexposure prophylaxis with oral tenofovir/emtricitabine reduces HIV acquisition rates, poor adherence to and acceptability of vaginal gels and the potential for evolving drug resistance have led to development of vaginal film formulations and other antiretroviral drugs, respectively, including the non-nucleoside reverse transcriptase inhibitor dapivirine. In this two-arm crossover study of a novel fast-dissolving dapivirine film and a previously studied semisolid dapivirine gel, 10 healthy women received a single 1.25 mg vaginal dose of each study product; one withdrew after the first dose. Clinical, pharmacokinetic, and antiviral pharmacodynamic assessments (ex vivo HIV-BaL challenge of tissue explants) were performed over 168 h postdose. Six of ten participants experienced mild to moderate adverse effects, similar between products, with no severe adverse events or adverse events attributed to study products. There were no statistically significant differences in plasma, cervicovaginal fluid (CVF), or cervical tissue dapivirine concentrations between the gel and film (all p > .05). CVF dapivirine concentrations were 1.5 and 6 log10 greater than tissue and plasma concentrations, respectively (p < .001). Both film and gel demonstrated reduced cervical tissue infectivity after ex vivo HIV challenge 5 h postdose, compared to baseline and 72-h postdose biopsies (p < .05 for gel, p = .06 for film). There was no difference in ex vivo explant HIV challenge between gel and film. The dapivirine film and gel performed similarly in terms of tolerability, pharmacokinetics, and antiviral effect. Dapivirine film may provide an alternative to pharmacokinetically comparable dapivirine gel formulations. Effectiveness remains to be tested.

Development of gellan gum containing formulations for transdermal drug delivery: Component evaluation and controlled drug release using temperature responsive nanogels

Enhancing skin permeation is important for development of new transdermal drug delivery formulations. This is particularly relevant for non-steroidal anti-inflammatory drugs (NSAIDs). To address this, semisolid gel and solid hydrogel film formulations containing gellan gum as a gelling agent were developed and the effects of penetration enhancers (dimethyl sulfoxide, isopropyl alcohol and propylene glycol) on transport of the NSAID diclofenac sodium was quantified. A transwell diffusion system was used to accelerate formulation development. After 4h, diclofenac flux from a superior formulation of the semisolid gel or the solid hydrogel film was 130±11μg/cm2h and 108±7μg/cm2h, respectively, and significantly greater than that measured for a currently available diclofenac sodium topical gel (30±4μg/cm2h, p<0.05) or solution formulation (44±6μg/cm2h, p<0.05) under identical conditions. Over 24h diclofenac transport from the solid hydrogel film was greater than that measured for any new or commercial diclofenac formulation. Entrapment of temperature-responsive nanogels within the solid hydrogel film provides temperature-activated prolonged release of diclofenac. Diclofenac transport was minimal at 22°C, when diclofenac is entrapped within temperature-responsive nanogels incorporated into the solid hydrogel film, but increased 6-fold when the temperature was increased to skin surface temperature of 32°C. These results demonstrate the feasibility of the semisolid gel and solid hydrogel film formulations that can include thermo-responsive nanogels for development of transdermal drug formulations with adjustable drug transport kinetics.

Enhancement of transdermal penetration and bioavailability of poorly soluble acyclovir using solid lipid nanoparticles incorporated in gel cream.

The objective of this work was to increase the amount of acyclovir in the basal epidermis, site of herpes virus simplex infection, using the solid lipid nanoparticles loaded gel cream as carriers. Solid lipid nanoparticles were prepared by high pressure homogenisation method and incorporated in a semisolid submicron gel cream. Acyclovir distribution into rat skin after topical application of solid lipid nanoparticles loaded gel cream was determined by fabricated Franz diffusion cell. The results showed that, the quantity of the acyclovir in the basal epidermis with the solid lipid nanoparticles loaded submicron gel cream was two folds times more than marketed acyclovir gel cream. This type of carrier can improve acyclovir loaded therapy since it increases drug retention in the basal epidermis.

Effect of extraction pH on heat-induced aggregation, gelation and microstructure of protein isolate from quinoa (Chenopodium quinoa Willd)

The aim of this study was to determine the influence of extraction pH on heat-induced aggregation, gelation and microstructure of suspensions of protein isolates extracted from quinoa (Chenopodium quinoa Willd). Quinoa seed protein was extracted by alkaline treatment at various pH values (pH 8 (E8), 9 (E9), 10 (E10) and 11 (E11)), followed by acid precipitation. The obtained protein isolates were freeze dried. The protein isolates E8 and E9 resulted in a lower protein yield as well as less protein denaturation. These isolates also had a higher protein purity, more protein bands at higher molecular weights, and a higher protein solubility in the pH range of 3–4.5, compared to the isolates E10 and E11. Heating the 10%w/w protein isolate suspensions E8 and E9 led to increased aggregation, and semi-solid gels with a dense microstructure were formed. The isolate suspensions E10 and E11, on the other hand, aggregated less, did not form self-supporting gels and had loose particle arrangements. We conclude that extraction pH plays an important role in determining the functionality of quinoa protein isolates.

Metastable hydrogels from aromatic dipeptides.

We demonstrate that the well-known self-assembling dipeptide diphenylalanine (FF) and its amidated derivative (FF-NH2) can form metastable hydrogels upon sonication of the dipeptide solutions. The hydrogels show instantaneous syneresis upon mechanical contact resulting in rapid expulsion of water and collapse into a semi-solid gel.