Design and evaluation of mucoadhesive vaginal tablets of tenofovir disoproxil fumarate for pre-exposure prophylaxis of HIV

Objective: To design and evaluate novel, feasible, safe, mucoadhesive intravaginal tablets of tenofovir disoproxil fumarate (TDF).

Significance: It may provide pre-exposure prophylaxis for women against HIV.

Methods: TDF intravaginal tablets were formulated employing poylvinylpyrrolidone (PVP) as the matrix forming polymer and various mucoadhesive polymers such as carbopol 934, 940, chitosan, and sodium carboxymethylcellulose (SCMC). Wet granulation was used. The evaluation involved testing drug-excipient compatibility, precompression parameters such as percentage yield, bulk density and tapped density of the granules, Carr’s index, Hausner ratio, angle of repose, post compression parameters such as color, shape, physical dimensions, weight variation, hardness, friability, swelling index, assay, in vitro dissolution study and ex vivo mucoadhesion studies.

Results: Based on in vitro evaluation, C1 was selected as the best formulation and evaluated further for release kinetics, curve fitting analysis, absorption studies using liquid chromatography-mass spectrometry (LC-MS) technique and histopathological assessment in female Sprague–Dawley rats. C1 followed Higuchi model kinetics. Accelerated stability study was as per ICH guidelines by keeping C1 at 40?±?2?°C and 75?±?5% RH for six months.

Conclusions: C1 was selected as the best formulation due to better swelling index (65.93% at 24?h), prolonged release of 100.62% cumulative drug release (CDR) at 24?h, superior mucoadhesion force (35.93?×?10² dynes/cm²) and retention time (16?h). The study revealed that C1 remained stable for six months. C1 showed nil systemic absorption which is desirable and according to histopathological study, C1, exhibited minimal damage on the rat vaginal epithelium indicating safety.     

Development,optimization, and characterization of a novel tea tree oil nanogel using response surface methodology

Purpose: To develop and optimize nanoemulsion (NE)-based emulgel (EG) formulation as a potential vehicle for topical delivery of tea tree oil (TTO).

Methodology: Central composite design was adopted for optimizing the processing conditions for NE preparation by high energy emulsification method viz. surfactant concentration, co-surfactant concentration, and stirring speed. The optimized NE was developed into emulgel (EG) using pH sensitive polymer Carbopol 940 and triethanolamine as alkalizer. The prepared EG was evaluated for its pH, viscosity, and texture parameters, ex vivo permeation at 37?°C and stability. Antimicrobial evaluation of EG in comparison to conventional gel and pure TTO was also carried out against selected microbial strains.

Results and discussion: Optimized NE had particle size and zeta potential of 16.23?±?0.411?nm and 36.11?±?1.234?mV, respectively. TEM analysis revealed the spherical shape of droplets. The pH of EG (5.57?±?0.05?) was found to be in accordance with the range of human skin pH. EG also illustrated efficient permeation (79.58?μL/cm²) and flux value (J_SS) of 7.96?μL cm²/h through skin in 10?h. Viscosity and texture parameters, firmness (9.3?±?0.08?g), spreadability (2.26?±?0.06?mJ), extrudability (61.6?±?0.05?mJ), and adhesiveness (8.66?±?0.08?g) depict its suitability for topical application. Antimicrobial evaluation of EG with same amount of TTO as conventional gel revealed broader zones of growth inhibitions against all the selected microbial strains. Moreover, EG was also found to be nonirritant (PII 0.0833). These parameters were consistent over 90 d.

Conclusion: TTO EG turned out to be a promising vehicle for the topical delivery of TTO with enhanced therapeutic efficacy.     

Nanocrystal-based drug delivery system of risperidone: lyophilization and characterization

Objective: In the present work nanocrystal-based formulation of risperidone (RIS) was proposed to overcome solubility issue of RIS, while lyophilization technique was used effectively, for conversion of RIS nanosuspension to solid state.

Significance: RIS nanosuspension was developed and stabilized with a combination of polycaprolactone and Pluronic^® F-68 as stabilizers. With focus on critical parameters like nature of cryoprotectants and effect of eutectic temperature on properties of nanosuspension, the suitability of lyophilization technique in improving the physical stability of prepared nanosuspension was also evaluated. Additionally, the developed nanocrystals were also assessed for their solid states properties.

Methods: Various process parameters affecting average particle size and polydispersity index (PDI), viz. drug to surfactant ratio, solvent to anti-solvent ratio, stirring speed, type of stabilizer were optimized. Assessment of lyophilization as a suitable solidification technique (for conversion to powder form) was done with selective cryoprotectants (trehalose dihydrate and sorbitol).

Results: The formulation was found to be stable at 4?°C for 3 months with size, PDI and zeta potential of 214?±?3.4?nm, 0.120, and –10.2?±?0.90?mV, respectively. Release profile of developed nanosuspension showed cumulative % release of ～90% in initial 10?h whereas the value for the unprocessed drug was ～11% in same time frame.

Conclusions: These findings suggest that developed formulation was able to enhance water solubility of the drug effectively and can be potentially used in the management of psychotic disorders.     

Pharmaceutical development of an amorphous solid dispersion formulation of elacridar hydrochloride for proof-of-concept clinical studies

Objective: A novel tablet formulation containing an amorphous solid dispersion (ASD) of elacridar hydrochloride was developed with the purpose to resolve the drug’s low solubility in water and to conduct proof-of-concept clinical studies.

Significance: Elacridar is highly demanded for proof-of-concept clinical trials that study the drug’s suitability to boost brain penetration and bioavailability of numerous anticancer agents. Previously, clinical trials with elacridar were performed with a tablet containing elacridar hydrochloride. However, this tablet formulation resulted in poor and unpredictable absorption which was caused by the low aqueous solubility of elacridar hydrochloride.

Methods: Twenty four different ASDs were produced and dissolution was compared to crystalline elacridar hydrochloride and a crystalline physical mixture. The formulation with highest dissolution was characterized for amorphicity. Subsequently, a tablet was developed and monitored for chemical/physical stability for 12 months at +15–25?°C, +2–8?°C and ?20?°C.

Results: The ASD powder was composed of freeze dried elacridar hydrochloride–povidone K30–sodium dodecyl sulfate (1:6:1, w/w/w), appeared fully amorphous and resulted in complete dissolution whereas crystalline elacridar hydrochloride resulted in only 1% dissolution. The ASD tablets contained 25?mg elacridar hydrochloride and were stable for at least 12 months at –20?°C.

Conclusions: The ASD tablet was considered feasible for proof-of-concept clinical studies and is now used as such.     

Nanoethosomal formulation of gammaoryzanol for skin-aging protection and wrinkle improvement: a histopathological study

Background: Free radical scavengers and antioxidants, with the main focus on enhanced targeting to the skin layers, can provide protection against skin ageing.

Objective: The aim of the present study was to prepare nanoethosomal formulation of gammaoryzanol (GO), a water insoluble antioxidant, for its dermal delivery to prevent skin aging.

Methods: Nanoethosomal formulation was prepared by a modified ethanol injection method and characterized by using laser light scattering, scanning electronic microscope (SEM) and X-ray diffraction (XRD) techniques. The effects of formulation parameters on nanoparticle size, encapsulation efficiency percent (EE%) and loading capacity percent (LC%) were investigated. Antioxidant activity of GO-loaded formulation was investigated in vitro using normal African green monkey kidney fibroblast cells (Vero). The effect of control and GO-loaded nanoethosomal formulation on superoxide dismutase (SOD) and malondialdehyde (MDA) content of rat skin was also probed. Furthermore, the effect of GO-loaded nanoethosomes on skin wrinkle improvement was studied by dermoscopic and histological examination on healthy humans and UV-irradiated rats, respectively.

Results: The optimized nanoethosomal formulation showed promising characteristics including narrow size distribution 0.17?±?0.02, mean diameter of 98.9?±?0.05?nm, EE% of 97.12?±?3.62%, LC% of 13.87?±?1.36% and zeta potential value of –15.1?±?0.9?mV. The XRD results confirmed uniform drug dispersion in the nanoethosomes structure. In vitro and in vivo antioxidant studies confirmed the superior antioxidant effect of GO-loaded nanoethosomal formulation compared with control groups (blank nanoethosomes and GO suspension).

Conclusions: Nanoethosomes was a promising carrier for dermal delivery of GO and consequently had superior anti-aging effect.     

Intradermal and follicular delivery of adapalene liposomes

Abstract

Background: Adapalene is a widely used topical anti-acne drug; however, it has many side effects. Liposomal drug delivery can play a major role by targeting delivery to pilosebaceous units, reducing side effects and offering better patient compliance.

Objective: To prepare and evaluate adapalene-encapsulated liposomes for their physiochemical and skin permeation properties.

Methods: A liposomal formulation of adapalene was prepared by the film hydration method and characterized for shape, size, polydispersity index (PDI), encapsulation efficiency and thermal behavior by techniques such as Zetasizer®, differential scanning calorimetry and transmission electron microscopy. Stability of the liposomes was evaluated for three months at different storage conditions. In vitro skin permeation studies and confocal laser microscopy were performed to evaluate adapalene permeation in pig ear skin and hair follicles.

Results: The optimized process and formulation parameters resulted in homogeneous population of liposomes with a diameter of 86.66?±?3.5?nm in diameter and encapsulation efficiency of 97.01?±?1.84% w/w. In vitro permeation studies indicated liposomal formulation delivered more drug (6.72?±?0.83?μg/cm²) in hair follicles than gel (3.33?±?0.26?μg/cm²) and drug solution (1.62?±?0.054?μg/cm²). Drug concentration delivered to the skin layers was also enhanced compared to other two formulations. Confocal microscopy images confirmed drug penetration in the hair follicles when delivered using the liposomal formulation.

Conclusion: Adapalene was efficiently encapsulated in liposomes and led to enhanced delivery in hair follicles, the desired target site for acne.     

Nanostructured lipid carriers engineered for intranasal delivery of teriflunomide in multiple sclerosis: optimization and in vivo studies

Background: Multiple sclerosis (MS) is one of the most severe autoimmune disorder of the central nervous system (CNS).

Objective: The present research work was aimed to formulate and investigate teriflunomide (TFM)-loaded intranasal (i.n.) nanostructured lipid carriers (NLC) for the treatment of multiple sclerosis (MS).

Methods: The TFM-loaded NLC (TFM-NLC) nanoparticles were prepared by melt emulsification ultrasonication method using biodegradable and biocompatible polymers. The Box–Behnken statistical design was applied to optimize the formulation. The optimized NLC formulation was subjected to evaluate for particle size, entrapment efficiency (%), in vitro and ex vivo permeation. The safety and efficacy of optimized formulations were demonstrated using pharmacodynamic, subacute toxicity and hepatotoxicity data.

Results: Experimental data demonstrated that optimized NLC formulation (F17) showed significant size (99.82?±?1.36?nm), zeta potential (?22.29?±?1.8?mV) and % entrapment efficiency (83.39?±?1.24%). Alternatively, ex vivo permeation of TFM mucoadhesive NLC (TFM-MNLC) and TFM-NLC was observed 830?±?7.6 and 651?±?9.8?µg/cm², respectively. Whereas, TFM-MNLC shows around 2.0-folds more J_ss than the TFM-NLC. Finally, TFM-MNLC (i.n.) formulation produced the rapid remyelination in cuprizone-treated animals and decreases the number of entries in open compartment of EPM when compared with negative control and TFM-NLC (oral) animals. Simultaneously, the nanoformulation did not reflect any gross changes in hepatic biomarkers and subacute toxicity when compared with control.

Conclusions: Hence it can be inferred that the nose-to-brain delivery of TFM-MNLC can be considered as effective and safe delivery for brain disorders.     

Dual cross-linked chitosan microspheres formulated with spray-drying technique for the sustained release of levofloxacin

Objective: This study was aimed to develop sustained drug release from levofloxacin (LF)-loaded chitosan (CS) microspheres for treating ophthalmic infections.

Significance: Dual cross-linked CS microspheres developed by the spray-drying technique displays significantly higher level of sustained drug release compared with non-cross-linked CS microspheres.

Methods: LF-loaded CS microspheres were prepared using the spray-drying technique, and then solidified with tripolyphosphate and glutaraldehyde as dual cross-linking agents. The microspheres were characterized by surface morphology, size distribution, zeta potential, encapsulation efficiency, and drug release profiles in vitro. The drug quantification was verified and analyzed by high-performance liquid chromatography (HPLC). The structural interactions of the CS with LF were studied with Fourier transform infrared spectroscopy. The effect of various influencing excipients in the formulation of the dual cross-linked CS microspheres on drug encapsulation efficiency and the drug release profiles were extensively investigated.

Result: The microspheres demonstrated high encapsulation efficiency (72.4?～?98.55%) and were uniformly spherical with wrinkled surface. The mean particle size was between 1020.7?±?101.9 and 2381.2?±?101.6?nm. All microspheres were positively charged (zeta potential ranged from 31.1?±?1.32 to 42.81?±?1.55?mV). The in vitro release profiles showed a sustained release of the drug and it was remarkably influenced by the cross-linking process.

Conclusion: This novel spray-drying technique we have developed is suitable for manufacturing LF-loaded CS microspheres, and thus could serve as a potential platform for sustained drug release for effective therapeutic application in ocular infections.     

Formulation design and optimization of novel soft glycerosomes for enhanced topical delivery of celecoxib and cupferron by Box–Behnken statistical design

Background: The present study describes glycerosomes (vesicles composed of phospholipids, glycerol and water) as a novel drug delivery system for topical application of celecoxib (CLX) and cupferron (CUP) compound.

Aim: The goal of this research was to design topical soft innovative vesicles loaded with CLX or CUP for enhancing the efficacy and avoiding systemic toxicity of CLX and CUP.

Methods: CLX and CUP loaded glycerosomes were prepared by hydrating phospholipid-cholesterol films with glycerol aqueous solutions (20–40%, v/v). Box–Behnken design, using Design-Expert® software, was the optimum choice to statistically optimize formulation variables. Three independent variables were evaluated: phospholipid concentration (X₁), glycerol percent (X₂) and tween 80 concentration (X₃). The glycerosomes particle size (Y₁), encapsulation efficiency percent (Y₂: EE %) and drug release (Y₃) were selected as dependent variables. The anti-inflammatory effect of CLX and CUP glycerosomal gel was evaluated by carrageenan-induced rat paw edema method followed by histopathological studies.

Results: The optimized formulations (CLX2* and CUP1*) showed spherical morphology under transmission electron microscopy, optimum particle size of 195.4?±?3.67?nm, 301.2?±?1.75?nm, high EE of 89.66?±?1.73%, 93.56?±?2.87%, high drug release of 47.08?±?3.37%, 37.60?±?1.89% and high cumulative amount of drug permeated in 8?h of 900.18?±?50.24, 527.99?±?34.90?µg.cm^?2 through hairless rat skin, respectively. They also achieved significant remarkable paw edema inhibition in comparison with the control group (p? Conclusion: Finally, the administration of CLX2* and CUP1* loaded glycerosomal gel onto the skin resulted in marked reduction of edema, congestive capillary and inflammatory cells and this approach may be of value in the treatment of different inflammatory disorders.     

Epinephrine doses delivered from auto-injectors stored at excessively high temperatures

Context: Prompt injection of epinephrine (adrenaline) from epinephrine auto-injectors (EAIs) is the primary treatment for anaphylaxis in out-of-hospital settings. Storage of EAIs at room temperature (25?°C) is advised; however, storage at excessively high temperatures sometimes occurs. To our knowledge, there are no previous publications on the doses of epinephrine ejected from EAIs after storage at such temperatures.

Objective: We examined the epinephrine doses delivered from activated EAIs stored constantly or cyclically at 70?°C.

Methods: Twenty-five in-date EAIs were stored constantly or cyclically at 70?°C (excessive heat) or 25?°C (controls) for 5?d or 10?d. EAIs were activated and the epinephrine doses in the ejected solutions were measured using HPLC-UV. The enantiomeric purity of epinephrine was also measured by HPLC-UV.

Results: Control EAIs ejected a volume of 0.300?±?0.006?mL containing 103.7?±?3.3% of labeled dose (LD). After 5?d or 10?d of constant storage at 70?°C and activation at 70?°C, EAIs ejected a volume of 0.367?±?0.008?mL containing 96.8?±?3.8% LD and 0.373?±?0.007?mL containing 77.7?±?3.3% LD, respectively. After 5?d of cyclic storage at 70?°C and cooling to 25?°C before activation, EAIs ejected a volume of 0.311?±?0.008?mL containing 87.2?±?1.9% LD. Under the experimental conditions of this study, the resultant chromatographic peaks of epinephrine solutions from all EAIs represented only the pure l-enantiomer of epinephrine.

Conclusion: EAIs should be stored under recommended conditions of the manufacturer. EAIs stored at excessively high temperatures cannot be used to treat humans while still hot, and when cooled, cannot be relied on to deliver the labeled epinephrine dose in anaphylaxis.     

Enhanced stability and permeation potential of nanoemulsion containing sefsol-218 oil for topical delivery of amphotericin B

Aim: To characterize the enhanced stability and permeation potential of amphotericin B nanoemulsion comprising sefsol-218 oil at varying pH and temperature of aqueous continuous phase.

Methodology: Several batches of amphotericin B loaded nanoemulsion were prepared and evaluated for their physical and chemical stability at different pH and temperature. Also, a comparative study of ex vivo drug permeation across the albino rat skin was investigated with commercial Fungisome® and drug solution at 37?°C for 24?h. The extent of drug penetrated through the rat skin was thereby evaluated using the confocal laser scanning microscopy (CLSM).

Results and conclusions: The optimized nanoemulsion demonstrated the highest flux rate 17.85?±?0.5?µg/cm²/h than drug solution (5.37?±?0.01?µg/cm²/h) and Fungisome® (7.97?±?0.01?µg/cm²/h). Ex vivo drug penetration mechanism from the developed formulations at pH 6.8 and pH 7.4 of aqueous phase pH using the CLSM revealed enhanced penetration. Ex vivo drug penetration studies of developed formulation comprising of CLSM revealed enhanced penetration in aqueous phase at pH 6.8 and 7.4. The aggregation behavior of nanoemulsion at both the pH was found to be minimum and non-nephrotoxic. The stability of amphotericin B was obtained in terms of pH, optical density, globular size, polydispersity index and zeta potential value at different temperature for 90 days. The slowest drug degradation was observed in aqueous phase at pH 7.4 with shelf life 20.03-folds higher when stored at 4?°C (3.8 years) and 5-fold higher at 25?°C (0.951 years) than at 40?°C. The combined results suggested that nanoemulsion may hold an alternative for enhanced and sustained topical delivery system for amphotericin B.     

Dissolution and precipitation behavior of ternary solid dispersions of ezetimibe in biorelevant media

Abstract

The effects of different formulations and processes on inducing and maintaining the supersaturation of ternary solid dispersions of ezetimibe (EZ) in two biorelevant media fasted-state simulated intestinal fluid (FaSSIF) and fasted-state simulated gastric fluid (FaSSGF) at different temperatures (25?°C and 37?°C) were investigated in this work.

Ternary solid dispersions of EZ were prepared by adding polymer PVP-K30 and surfactant poloxamer 188 using melt-quenching and spray-drying methods. The resulting solid dispersions were characterized using scanning electron microscopy, differential scanning calorimetry (DSC), modulated DSC, powder X-ray diffraction and Fourier transformation infrared spectroscopy. The dissolution of all the ternary solid dispersions was tested in vitro under non-sink conditions.

All the prepared solid dispersions were amorphous in nature. In FaSSIF at 25?°C, the melt-quenched (MQ) solid dispersions of EZ were more soluble than the spray-dried (SD) solid dispersions and supersaturation was maintained. However, at 37?°C, rapid and variable precipitation behavior was observed for all the MQ and SD formulations. In FaSSGF, the melting method resulted in better solubility than the spray-drying method at both temperatures.

Ternary solid dispersions show potential for improving solubility and supersaturation. However, powder dissolution experiments of these solid dispersions of EZ at 25?°C may not predict the supersaturation behavior at physiologically relevant temperatures.     

Design and in vitro characterization of buccoadhesive tablets of timolol maleate

Objective: The purpose of this work was to develop and evaluate buccoadhesive tablets of timolol maleate (TM) due to its potential to circumvent the first-pass metabolism and to improve its bioavailability.

Methods: The tablets were prepared by direct compression using two release modifying polymers, Carbopol 974P (Cp-974p) and sodium alginate (SA). A 3² full factorial design was employed to study the effect of independent variables, Cp-974p and SA, in various proportions in percent w/w, which influences the in vitro drug release and bioadhesive strengths. Physicochemical properties of the drug were evaluated by ultraviolet, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and powder X-ray diffraction (P-XRD). Tablets were evaluated for hardness, thickness, weight variation, drug content, surface pH, swelling index, bioadhesive force and in vitro drug release.

Results: The FTIR and DSC studies showed no evidence of interactions between drug, polymers and excipients. The P-XRD study revealed that crystallinity of TM remain unchanged in optimized formulation tablet. Formulation F9 achieves an in vitro drug release of 98.967%?±?0.28 at 8?h and a bioadhesive force of 0.088 N?±?0.01211.

Conclusion: We successfully developed buccal tablet formulations of TM and describe a non-Fickian-type anomalous transport as the release mechanism.     

Development and pharmacokinetic evaluation of alginate-pectin polymeric rafts forming tablets using box behnken design

Abstract

Raft is an emerging drug delivery system, which is suitable for controlled release drug delivery and targeting. The present study aimed to evaluate the physico-chemical properties of raft, in vitro release of pantoprazole sodium sesquihydrate and conduct bioavailability studies. Box behnken design was used with three independent and dependent variables. Independent variables were sodium alginate (X₁), pectin (X₂) and hydroxypropyl methyl cellulose K100M (X₃) while dependent variables were percentage drug release at 2 (Y₂), 4 (Y₄) and 8?h (Y₈). The developed rafts were evaluated by their physical and chemical properties. Fourier transform infrared spectroscopy and differential scanning calorimetry were used to study the chemical interaction and thermal behaviour of drug with polymers. Alginate and pectin contents of R9 formulation were 99.28% and 97.29%, respectively, and acid neutralization capacity was 8.0. R9 formulation showed longer duration of neutralization and nature of raft was absorbent. The raft of R9 formulation showed 98.94% release of PSS at 8?h in simulated gastric fluid. Fourier transform infrared spectroscopy showed no chemical interaction and differential scanning calorimetry indicated endothermic peaks at 250?°C for pantoprazole sodium sesquihydrate. t_max for the test and reference formulations were 8?±?2.345?h and 8?±?2.305?h, respectively. C_max of test and reference formulations were 46.026?±?0.567?µg/mL and 43.026?±?0.567?µg/mL, respectively. AUC_(0-t) of the test and reference formulations were 472.115?±?3.467?µg?×?h/mL and 456.105?±?2.017?µg?×?h/mL, respectively. Raft forming system successfully delivered the drug in controlled manner and improved the bioavailability of drugs.     

Preparation and optimization of doxorubicin-loaded albumin nanoparticles using response surface methodology

Background: The objective of this work was to optimize the preparation of doxorubicin-loaded albumin nanoparticles (Dox-A-Nps) through desolvation procedures using response surface methodology (RSM). A central composite design (CCD) for four factors at five levels was used in this study.

Method: Albumin nanoparticles were prepared through a desolvation method and were optimized in the aid of CCD. Albumin concentration, amount of doxorubicin, pH values, and percentage of glutaraldehyde were selected as independent variables, particle size, zeta potential, drug loading, encapsulation efficiency, and nanoparticles yield were chosen as response variables. RSM and multiple response optimizations utilizing a quadratic polynomial equation were used to obtain an optimal formulation.

Results: The optimal formulation for Dox-A-Nps was composed of albumin concentration of 17?mg/ml, amount of doxorubicin of 2?mg/ml, pH value is 9 and percentage of glutaraldehyde of 125% of the theoretic amount, under which the optimized conditions gave rise to the actual average value of mean particle size (151?±?0.43?nm), zeta potential (?18.8?±?0.21 mV), drug loading efficiency (21.4?±?0.70%), drug entrapment efficiency (76.9?±?0.21%) and nanoparticles yield (82.0?±?0.34%). The storage stability experiments proved that Dox-A-Nps stable in 4°C over the period of 4 months. The in vitro experiments showed a burst release at the initial stage and followed by a prolonged release of Dox from albumin nanoparticles up to 60?h.

Conclusions: This study showed that the RSM-CCD method could efficiently be applied for the modeling of nanoparticles, which laid the foundation of the further research of immuno nanoparticles.     

Effect of Zr on microstructure and mechanical properties of the Al–Cu–Er alloy

ABSTRACT

The microstructure and mechanical properties of the Al–4Cu–2.7Er–0.3Zr alloy were investigated. The precipitates of the L1₂ structured phase with sizes 37?±?12?nm were formed in lines and homogenously distributed inside the aluminium matrix after annealing at 605°C for 1?h. The as-rolled Al–4Cu–2.7Er–0.3Zr alloy developed an increased hardness after 1?h annealing at 100–550°C and 0.5–6?h annealing at 150–250°C due to precipitation of the Al₃(Er,Zr) phase. Addition of Zirconium improved the tensile properties relative to those of the Zr-free alloy by approximately 20?MPa: yield strength?=?273–296?MPa and ultimate tensile strength?=?296–328?MPa in the alloys annealed at 100–150°C.     

Characterization of an antioxidant surfactant-free topical formulation containing Castanea sativa leaf extract

Context: Inclusion of antioxidants in topical formulations can contribute to minimize oxidative stress in the skin, which has been associated with photoaging, several dermatosis and cancer.

Objective: A Castanea sativa leaf extract with established antioxidant activity was incorporated into a semisolid surfactant-free formulation. The objective of this study was to perform a comprehensive characterization of this formulation.

Materials and methods: Physical, microbiological and functional stability were evaluated during 6?months storage at 20?°C and 40?°C. Microstructure elucidation (cryo-SEM), in vitro release and in vivo moisturizing effect (Corneometer® CM 825) were also assessed.

Results and discussion: Minor changes were observed in the textural and rheological properties of the formulation when stored at 20?°C for 6?months and the antioxidant activity of the plant extract remained constant throughout the storage period. Microbiological quality was confirmed at the end of the study. Under accelerated conditions, higher modifications of the evaluated parameters were observed. Cryo-SEM analysis revealed the presence of oil droplets dispersed into a gelified external phase. The release rate of the antioxidant compounds (610?±?70?µgh^?0.5) followed Higuchi model. A significant in vivo moisturizing effect was demonstrated, that lasted at least 4?h after product’s application.

Conclusion: The physical, functional and microbiological stability of the antioxidant formulation was established. Specific storage conditions should be recommended considering the influence of temperature on the stability. A skin hydration effect and good skin tolerance were also found which suggests that this preparation can be useful in the prevention or treatment of oxidative stress-mediated dysfunctions.     

Lysozyme-loaded lipid-polymer hybrid nanoparticles: preparation,characterization and colloidal stability evaluation

Context: Lipid-polymer hybrid nanoparticles (LPNPs) are polymeric nanoparticles enveloped by lipid layers, which have emerged as a potent therapeutic nanocarrier alternative to liposomes and polymeric nanoparticles.

Objective: The aim of this work was to develop, characterize and evaluate LPNPs to deliver a model protein, lysozyme.

Materials and methods: Lysozyme-loaded LPNPs were prepared by using the modified w/o/w double-emulsion-solvent-evaporation method. Poly-?-caprolactone (PCL) was used as polymeric core material and tripalmitin:lechitin mixture was used to form a lipid shell around the LPNPs. LPNPs were evaluated for particle size distribution, zeta potential, morphology, encapsulation efficiency, in vitro drug release, stability and cytotoxicity.

Results: The DLS measurement results showed that the particle size of LPNPs ranged from 58.04?±?1.95?nm to 2009.00?±?0.52?nm. The AFM and TEM images of LPNPs demonstrate that LPNPs are spherical in shape. The protein-loading capacity of LPNPs ranged from 5.81% to 60.32%, depending on the formulation parameters. LPNPs displayed a biphasic drug release pattern with a burst release within 1?h, followed by sustained release afterward. Colloidal stability results of LPNPs in different media showed that particle size and zeta potential values of particles did not change significantly in all media except of FBS 100% for 120?h. Finally, the results of a cellular uptake study showed that LPNPs were significantly taken up by 83.3% in L929 cells.

Conclusion: We concluded that the LPNPs prepared with PCL as polymeric core material and tripalmitin:lechitin mixture as lipid shell should be a promising choice for protein delivery.     

Effect of primary drying temperature on process efficiency and product performance of lyophilized Ertapenam sodium

Abstract

The present work aimed to investigate the impact of primary drying temperature on lyophilization process efficiency and product performance of lyophilized Ertapenam sodium (EPM). Phase behavior of EPM formulation (200?mg/mL) using differential scanning calorimetry (DSC) and freeze drying microscopy (FDM) showed Tg′ at ?28.3?°C (onset) and Tc at ?25.0?°C (onset), respectively. The formulation was freeze dried at different product temperature (Tp) during primary drying, using (a) conservative cycle (CC) where the maximum Tp (?31.9?°C) <Tg′, (b) aggressive cycle 01 (AC01) where the maximum Tp (?24.8?°C) >Tg′, and (c) AC02 where the maximum Tp (?21.0?°C) >Tc. The drying kinetics revealed that the sublimation rate was increased from 0.128?g/h/vial in CC to 0.159 and 0.182?g/h/vial in AC01 and AC02, respectively. This ultimately reduced the primary drying time of 208?min in CC to 145?min in AC01 and to 103?minutes in AC02. Morphological evaluation of cake using scanning electron microscopy (SEM) and texture analysis revealed that AC01 lead to induction of microcollapse, whereas AC02 resulted in collapsed cake. Furthermore, the microcollapsed formulations showed similar physicochemical stability to CC formulation, whereas collapsed cake showed significant degradation of EPM and increased degradation on stress stability. The study highlights that primary drying with microcollapse can be utilized to improve the process efficiency without compromising product quality of amorphous EPM.     

Development and in vitro evaluation of a nanoemulsion for transcutaneous delivery

Objective: The purpose of this study is to develop a nanoemulsion formulation for its use as a transcutaneous vaccine delivery system.

Materials and methods: With bovine albumin-fluorescein isothiocyanate conjugate (FITC-BSA) as a vaccine model, formulations were selected with the construction of pseudo-ternary phase diagrams and a short-term stability study. The size of the emulsion droplets was furthered optimized with high-pressure homogenization. The optimized formulation was evaluated for its skin permeation efficiency. In vitro skin permeation studies were conducted with shaved BALB/c mice skin samples with a Franz diffusion cell system. Different drug concentrations were compared, and the effect of the nanoemulsion excipients on the permeation of the FITC-BSA was also studied.

Results: The optimum homogenization regime was determined to be five passes at 20?000?psi, with no evidence of protein degradation during processing. With these conditions, the particle diameter was 85.2?nm?±?15.5?nm with a polydispersity index of 0.186?±?0.026 and viscosity of 14.6 cP?±?1.2 cP. The optimized formulation proved stable for 1 year at 4?°C. In vitro skin diffusion studies show that the optimized formulation improves the permeation of FITC-BSA through skin with an enhancement ratio of 4.2 compared to a neat control solution. Finally, a comparison of the skin permeation of the nanoemulsion versus only the surfactant excipients resulted in a steady state flux of 23.44?μg/cm²/h for the nanoemulsion as opposed to 6.10?μg/cm²/h for the emulsifiers.

Conclusion: A novel nanoemulsion with optimized physical characteristics and superior skin permeation compared to control solution was manufactured. The formulation proposed in this study has the flexibility for the incorporation of a variety of active ingredients and warrants further development as a transcutaneous vaccine delivery vehicle.