Preliminary Stability Studies Research Articles

(SiFA)SeFe: A Hydrophilic Silicon-Based Fluoride Acceptor Enabling Versatile Peptidic Radiohybrid Tracers.

The radiohybrid (rh) concept to design targeted (and chemically identical) radiotracers for imaging or radionuclide therapy of tumors has gained momentum. For this strategy, a new bifunctional Silicon-based Fluoride Acceptor (SiFA) moiety (SiFA)SeFe was synthesized, endowed with improved hydrophilicity and high versatility of integration into rh-compounds. Preliminary radiolabeling and stability studies under different conditions were conducted using model bioconjugate peptides. Further, three somatostatin receptor 2 (sstR2)-targeted rh-compounds ((SiFA)SeFe-rhTATE1-3, TATE = (Tyr3)-octreotate) were developed. Compound (SiFA)SeFe-rhTATE3, enables labeling with 18F for PET imaging or chelation of 177Lu for therapy. The rh-compounds possess comparable receptor binding affinity and in vitro performance as good as the clinically proven gold standards. SstR2-specificity was further shown for (SiFA)SeFe-rhTATE2 using the chicken chorioallantoic membrane (CAM) model. The biodistribution of two compounds in mice showed high accumulation in tumors and excretion via the kidneys, demonstrating the clinical applicability of the (SiFA)SeFe moiety.

Development of Losartan Orally Disintegrating Tablets by Direct Compression: a Cost-Effective Approach to Improve Paediatric Patient's Compliance.

The development of suitable dosage forms is essential for an effective pharmacological treatment in children. Orally disintegrating tablets (ODTs) are attractive dosage forms that avoid swallowing problems, ensure dosage accuracy and are easy to administer as they disintegrate in the oral cavity. This study aimed to develop ODTs containing losartan potassium (LP) for the treatment of arterial hypertension in children. The ODTs, produced by the cost-effective manufacturing process of direct compression, consisted of a mixture of diluent, superdisintegrant, glidant and lubricant. Five superdisintegrants (croscarmellose sodium, two grades of crospovidone, sodium starch glycolate and pregelatinized starch) were tested (at two concentrations), and combined with three diluents (mannitol, lactose and sorbitol). Thus, thirty formulations were evaluated based on disintegration time, hardness and friability. Two formulations, exhibiting the best results concerning disintegration time (< 30s), hardness and friability (≤ 1.0%), were selected as the most promising ones for further evaluation. These ODTs presented favourable drug-excipient compatibility, tabletability and flow properties. The in vitro dissolution studies demonstrated 'very rapid' drug release. Preliminary stability studies highlighted the requirement of a protective packaging. All quality properties retained appropriate results after 12months of storage in airtight containers. In conclusion, the ODTs were successfully developed and characterised, suggesting a potential means to accomplish a final prototype that enables an improvement in childhood arterial hypertension treatment.

Extraction Optimization and Qualitative/Quantitative Determination of Bioactive Abietane-Type Diterpenes from Three Salvia Species (Common Sage, Greek Sage and Rosemary) by 1H-qNMR.

The objective of this study was the optimization of the extraction process and the qualitative and quantitative determination of the bioactive metabolites: 12-O-methylcarnosic acid (12MCA), carnosic acid (CA), carnosol (CS), 7-O-methyl-epi-rosmanol (7MER) and rosmanol (RO) in infusions, decoctions, turbulent flow extracts, tinctures and oleolites from three Salvia species: Salvia officinalis L. (common sage, SO), Salvia fruticosa Mill. (Greek sage, SF) and Salvia rosmarinus Spenn (syn Rosmarinus officinalis L.) (rosemary, SR), using Quantitative Proton Nuclear Magnetic Resonance Spectroscopy (1H-qNMR). Regarding the aqueous extracts, decoctions appeared to be richer sources of the studied metabolites than infusions among the three plants. For SR, the turbulent flow extraction under heating was the most efficient one. The optimum time for the preparation of decoctions was found to be 5 min for SF and SO and 15 min for SR. It is noteworthy that SR tinctures were not stable in time due to decomposition of the abietane-type diterpenes CA and CS because of the polar solvent used for their preparation. Contrary to this finding, the oleolites of SR appeared to be very stable. Olive oil as a solvent for extraction was very protective for the contained abietane-type diterpenes. A preliminary stability study on the effect of the storage time of the SF on the abietane-type diterpenes content showed that the total quantity of abietanes decreased by 16.51% and 40.79% after 12 and 36 months, respectively. The results of this investigation also demonstrated that 1H-qNMR is very useful for the analysis of sensitive metabolites, like abietane-type diterpenes, that can be influenced by solvents used in chromatographic analysis.

A dispersion analysis of uniformly high order, interior and boundaries, mimetic finite difference solutions of wave propagation problems

A preliminary stability and dispersion study for wave propagation problems is developed for mimetic finite difference discretizations. The discretization framework corresponds to the fourth-order staggered-grid Castillo-Grone operators that offer a sextuple of free parameters. The parameter-dependent mimetic stencils allow problem discretization at domain boundaries and at the neighbor grid cells. For arbitrary parameter sets, these boundary and near-boundary mimetic stencils are lateral, and we here draw first steps on the parametric dependency of the stability and dispersion properties of such discretizations. As a reference, our analyses also present results based on Castillo-Grone parameters leading to mimetic operators of minimum bandwidth that have been previously applied in similar physical problems. The most interior parameter-dependent mimetic stencils exhibit a specific Toeplitz-like structure, which reduces to the standard central finite difference formula for staggered differentiation at grid interior. Thus, our results apply to the whole discretization grid. The study done for the 1-D problem could be applied to the discretization of a free surface boundary condition along an orthogonal gridline to this boundary.

Development and evaluation of the in vitro schistosomicidal activity of solid dispersions based on 2-(-5-bromo-1-H-indole-3-yl-methylene)-N-(naphthalene-1-ylhydrazine-carbothiamide

Among all the neglected diseases, schistosomiasis is considered the second most important parasitic infection after malaria. Praziquantel is the most widely used drug for this disease, but its exclusive use may result in the development of drug-resistant schistosomiasis. To increase the control of the disease, new drugs have been developed as alternative treatments, among them 2-(-5-bromo-1-h-indole-3-yl-methylene)-N-(naphthalene-1-ylhydrazine-carbothiamide (LQIT/LT-50), which showed promising schistosomicidal activity in nonclinical studies. However, LQIT/LT-50 presents low solubility in water, resulting in reduced bioavailability. To overcome this solubility problem, the present study aimed to develop LQIT/LT-50 solid dispersions for the treatment of schistosomiasis. Solid dispersions were prepared through the solvent method using Soluplus©, polyethylene glycol (PEG) or polyvinylpyrrolidone (PVP K-30) as hydrophilic carriers. The formulations with the best results in the compatibility tests, aqueous solubility and preliminary stability studies have undergone solubility tests and physicochemical characterizations by Fourier-transform infrared spectroscopy (FTIR), x-ray diffractometry (XRD), exploratory differential calorimetry (DSC), thermogravimetry (TG) and Raman spectroscopy. Finally, the schistosomicidal activity was evaluated in vitro. The phycochemical analyzes showed that when using PVP K-30, there was an interaction between the PVP K-30 and LQIT/LT-50, proving the successful development of the solid dispersion. Furthermore, an increase in the solubility of the new system was observed (LQIT/LT-50:PVP K-30) in addition to the improvement in the in vitro shistosomidal activity at 1:4 (w/w) molar ratio (i.e., 20% drug loading) when compared to LQIT/LT-50 alone. The development of the LQIT/LT-50:PVP K-30 1:4 solid dispersion is encouraging for the future development of new pharmaceutical solid formulations, aiming the schistosomicidal treatment.

The Potential of Mangifera indica L. Peel Extract to Be Revalued in Cosmetic Applications.

The constant growth of the cosmetic industry, together with the scientific evidence of the beneficial properties of phytochemicals, has generated great interest in the incorporation of bioactive extracts in cosmetic formulations. This study aims to evaluate the bioactive potential of a mango peel extract for its incorporation into cosmetic formulations. For this purpose, several assays were conducted: phytochemical characterization; total phenolic content (TPC) and antioxidant potential; free-radical scavenging capacity; and skin aging-related enzyme inhibition. In addition, the extract was incorporated into a gel formulation, and a preliminary stability study was conducted where the accelerated (temperature ramp, centrifugation, and heating/cooling cycles) and long-term (storage in light and dark for three months) stability of the mango peel formulations were evaluated. The characterization results showed the annotation of 71 compounds, gallotannins being the most representative group. In addition, the mango peel extract was shown to be effective against the •NO radical with an IC50 of 7.5 mg/L and against the hyaluronidase and xanthine oxidase enzymes with IC50 of 27 mg/L and 2 mg/L, respectively. The formulations incorporating the extract were stable during the stability study. The results demonstrate that mango peel extract can be a by-product to be revalorized as a promising cosmetic ingredient.

Effect of Incorporating a Biowax Derived from Hydroprocessing of Crude Palm Oil in a Facial Cream and a Blemish Balm Cream

Most waxes used as cosmetic ingredients are derived from the petrochemical industry. A modern alternative to this complex synthesis approach is the hydrotreatment of palm oil; thus, the aim of this study is to evaluate the effect of incorporating a biowax derived from hydroprocessing of crude palm oil as a new natural cosmetic ingredient in facial cream and BB cream. Therefore, two water in oil (W/O) emulsions, one including pigments, with five different weight percentages were developed and subjected to further sensory evaluation by a trained panel to estimate the level of acceptance. Moreover, resistance to centrifugation, pH, spreadability, phase separation, viscosity and storage modulus were the parameters evaluated in a preliminary stability study using thermal stress. Sensory analysis showed that the highest level of acceptance was obtained between 3% and 9 wt% biowax. For both prototypes, increasing biowax percentage led to a greater effect on stickiness, the viscosity increased, and extensibility decreased. The formulations were able to maintain their pH. The best stability for BB cream was observed at 9%, since the changes in the properties were slight. For facial cream, the emulsion was more stable at intermediate biowax content. It was observed that biowax exhibits favorable characteristics as an emollient or thickening agent. Finally, the formulations with the best stability and sensory characteristics were obtained at 9 wt% biowax.

Formulation and evaluation of retinyl palmitate and vitamin E nanoemulsion for skin care

Background: Improving and maintaining the skin integrity and health are the most essential targets in long-term care. The aim of this study is to formulate a serum of retinyl palmitate (RP) and vitamin E (VE) as nanoemulsion (NE) for achieving healthy skin. Methods: The solubility of RP and VE was studied in different oils. The NEs were prepared using oil, water, and different surfactant-co-surfactant mixtures, and then the medicated nanoemulsion was prepared by addition of 0.5% RP and VE to the oil phase, and vitamin C as an antioxidant to the aqueous phase with different preservatives. The prepared NE was characterized in terms of particle size, charge, rheology, diffusion, and irritation to the skin. Results and conclusion: The data showed that the highest solubility of both RP and VE was in safflower oil. Tween 20, Ceteareth 20 with ethanol, PEG 200, and cremophor RH40. This combination was able to produce NE with good integrity and acceptable particle size. The prepared formulations gave particle size of 60–70 nm and showed Newtonian flow. Irritation tests on rats showed that the formula was safe to be applied on the skin with no signs of irritation up to 72 hours. A preliminary stability study at room temperature showed good stability up to 6 weeks. In conclusion, RP and VE could be formulated successfully as NE with good stability and physical characteristics.

A preliminary study of chemical property and thermal stability of potassium chloride encapsulated in starch-alginate matrix

A potassium controlled-release fertilizer was fabricated in a starch-alginate matrix by using calcium chloride as a cross-linker. 16 formulas were designed with varying amounts of alginate and potassium chloride with the same amount of starch and calcium chloride, and most of the formulas can form beads successfully. High sodium alginate and low potassium chloride assembled better shape and higher encapsulation efficiency. The highest encapsulation efficiency ratio of starch, sodium alginate, and potassium chloride was 5:1:10 in the 16 formulas. The bonding of alginate and starch, and calcium chloride were evidenced by FTIR, and the study of TGA revealed good thermal stability and compatibility between the polymers and potassium chloride.

Cichoric acid aerosol for inhalation therapy in respiratory syncytial virus

Cichoric acid (CA) is a caffeic acid derivative, which has significant anti respiratory syncytial virus (RSV) effect and low toxicity. However, due to the low oral bioavailability and poor intestinal absorption of CA, it is not suitable to be made into oral preparations. In this study, CA was made into metered dose inhaler (MDI), allowing the drug to target the site of action, thus achieving more effective treatment. Through preliminary experiments, the drug content and prescription composition of the preparation were determined. Clarity and stability of solution were used as indexes to screen the composition of latent solvent. Single factor and orthogonal test were used to optimize the amount of latent solvent in CA-MDI, and the optimal prescription was verified. The aerosol prepared according to the optimal formula was characterized and preliminary stability was studied. The final formula of CA-MDI was: CA 15 mg, absolute ethanol 1 g, propylene glycol 0.4 g and 1,1,1,2-tetrafluoroethane 10 g. CA-MDI was prepared with the best prescription, with the specification of 150 actuation per bottle and 75 μg per actuation. After quality inspection, three batches of inhaled aerosols showed that the main drug content per bottle was 77.91 ± 1.63 μg (n = 3), and the total number of bottles was 185 ± 3 (n = 3), all of which met the standards of China Pharmacopoeia and the proposed specifications. The preliminary stability study showed that the quality of inhaled aerosols in CA was stable and reliable.

Rapidly accelerated development of neutralizing COVID-19 antibodies by reducing cell line and CMC development timelines.

Since the Coronavirus Disease 2019(COVID-19) outbreak, unconventional cell line development (CLD) strategies have been taken to enable development of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)-neutralizing antibodies at expedited speed. We previously reported a novel chemistry, manufacturing, and control (CMC) workflow and demonstrated a much-shortened timeline of 3-6 months from DNA to investigational new drug (IND) application. Hereafter, we have incorporated this CMC strategy for many SARS-CoV-2-neutralizing antibody programs at WuXi Biologics. In this paper, we summarize the accelerated development of a total of seven antibody programs, some of which have received emergency use authorization approval in less than 2 years. Stable pools generated under good manufacturing practice (GMP) conditions consistently exhibited similar productivity and product quality at different scales and batches, enabling rapid initiation of phase I clinical trials. Clones with comparable product quality as parental pools were subsequently screened and selected for late-stage development and manufacturing. Moreover, a preliminary stability study plan was devised to greatly reduce the time required for final clone determination and next-generation sequencing-based viral testing was implemented to support rapid conditional release of the master cell bankfor GMP production. The successful execution of these COVID-19 programs relies on our robust, fit for purpose, and continuously improving CLD platform. The speed achieved for pandemic-related biologics development may innovate typical biologics development timelines and become a new standard in the industry.

Development, Quality by Design-Based Optimization, and Stability Assessment of Oral Liquid Formulations Containing Baclofen for Hospital Use.

The absence of oral liquid pharmaceutical forms appropriate for use in pediatric and adult patients with difficulty swallowing is a public health problem, especially in the hospital context. Baclofen is a muscle relaxant of choice for treating spasticity, generally marketed only in tablet form, highlighting the need for liquid formulations to facilitate dose adjustment, administration, and swallowing. The present study aimed to develop oral liquid formulations containing baclofen, optimize them through the quality by design approach, and evaluate their physicochemical and microbiological stability. Preformulation and preliminary stability studies were carried out for the development of formulations. Experimental screening and optimization designs resulted in eleven experiments for each step that were evaluated for 28days. A stability-indicating method by high-performance liquid chromatography presented linearity, low limits of detection and quantification, precision, accuracy, and robustness. The experimental design led to two optimized formulations containing baclofen, glycerin, potassium sorbate, citric acid, ultrapure water, flavor, and sucrose syrup or sodium carboxymethylcellulose solution as a vehicle, the last one with sucralose as a sweetener. The formulations were placed in amber glass flasks and subjected to a physicochemical and microbiological stability study. Both formulations showed physicochemical and microbiological stability when stored at room temperature and refrigerated for 84days. The results of this study may serve as a reference in the preparation of liquid oral formulations containing baclofen in the hospital routine and collaborate with the safety and adherence to the treatment of adult and pediatric patients.

Deformable Nanovesicle-Loaded Gel for Buccal Insulin Delivery.

Deformable nanovesicles (DNVs) have been widely used in oral mucosal delivery studies of biomolecular drugs. However, their development for oral mucosal preparations has been limited by their physical and chemical instability, the need for small oral volumes, and the complexity of the oral microenvironment. This study aimed to develop a more suitable buccal delivery system for DNVs with improved storage stability. Preliminary stability studies investigated different gel types, the effects of different hydrophilic gel matrices, and matrix temperature sensitivity using DNVs loaded with insulin-phospholipid complex (IPC-DNVs). A temperature-sensitive gel encapsulating IPC-DNVs (IPC-DNV-TSG) prepared with 2% w/v gelatin was stable at 4 °C for three months and maintained an excellent hypoglycemic effect. The delivery efficiency of IPC-DNVs and IPC-DNV-TSG was compared using a TR146 cell model, revealing that cell viability remained high. Cellular uptake was slightly lower for IPC-DNV-TSG than for IPC-DNVs, but total transport did not differ significantly between the two groups, which may have been related to the viscosity of IPC-DNV-TSG and the hydrophilicity, cell adhesion properties, and biocompatibility of gelatin. Moreover, neither IPC-DNVs nor IPC-DNV-TSG induced significant mucosal irritation in rabbit tongue tissue sections. The study findings demonstrate a promising method for possible use as oral mucosal delivery of peptide drugs.

Optimization of preparation technology for Acanthopanax senticosus total saponins microemulsion by D-optimal mixture design and intestinal absorption characteristics

Following the preparation of Acanthopanax senticosus total saponins microemulsion, the formulation and preparation technology were optimized and the quality was evaluated. The absorption characteristics of A. senticosus total saponins microemulsion by the self-microemulsifying drug delivery system(SMEDDS) were investigated in the unidirectional intestinal perfusion model in vivo. The oil phase, mass ratio(K_m), number of revolutions, and drug concentration were subjected to single-factor investigation with the area of pseudo-ternary phase diagram as the index. The process was optimized by D-optimal mixture design with the particle size as the index, and then the appearance, morphology, and particle size were investigated. The mass concentrations of eleutherosides B and E in the microemulsion were determined. The results showed that the optimum formulation of A. senticosus total saponins microemulsion was determined as follows: 20.8% of water phase, 31.2% of isopropyl palmitate, and 48.0% of soybean phospholipid and absolute ethanol(K_m=1∶1). As revealed by the observation under a transmission electron microscope, the microemulsion exhibited homogeneous dispersion and was a spherical emulsion droplet in the water-in-oil type. At room temperature, the pH value was 5.19, the refractive index 1.416 5, the average particle size(26.47±0.04)nm, and the polydispersity index(PDI) 0.118±0.03. The content of the eleutherosides B and E was 0.038 9 and 0.166 4 mg·mL~(-1), respectively. The preliminary stability study showed that the solution was clear and transparent within 30 d, without stratification or content change, indicating good stability. The absorption of microemulsion in each intestinal segment was significantly improved as compared with that of the A. senticosus total saponins, with the best absorption effect detected in the ileum, which has laid a foundation for further development and utilization of A. senticosus.

Eye Cosmeceutical Formulations with Roasted Coffee Oil in Free and Microencapsulated Forms: Development and Preliminary Stability Study

AbstractThis research aims to develop eye cosmeceutical formulations with roasted coffee oil. Oil is used in form and microencapsulated forms. A preliminary stability study is performed, and base formulation (BF) is used for comparison. All formulations are stable and firm. Formulations with oil in free (OF) or microencapsulated (MOF) form show color and aroma of coffee. Initially, MOF is the most acid, and BF shows the highest peroxide value (PV) and the lowest sun protection factor (SPF) values and no antioxidant activity (AA). OF and MOF show AA and high SPF ; these parameters are little affected by storage, and an increase in PV is observed only for BF. Cosmeceutical formulations with roasted coffee oil present stability and good potential for dermocosmetic products.Practical Applications: Coffee oil is known for its AA and protection against sunlight UV radiation, so it fits the interest of cosmetics and personal care producers for bioactive ingredients from natural sources. The cosmetics industry uses green coffee oil; however, roasted coffee oil is of more interest since it is a coproduct of the soluble coffee industry. The authors are unaware of studies proposing the use of microcapsules (produced by complex coacervation) of roasted coffee oil in cosmeceutical formulations.

Ceftaroline fosamil: development a rapid HPLC method indicating stability and bioassay for determination in pharmaceutical formulation, stability and cytotoxicity studies

The present study reports the development and validation of a microbiological assay. To assess this methodology, the method was developed and validated for the quantification of CEF by high performance liquid chromatography (HPLC). The validation of the microbial assay by diffusion method in 3x3 cylinder agar presented showed satisfactory results as to specificity, linearity in the range of 2.0 - 8.0 μg.mL-1, precision (109.42 %), accuracy (102.3 %), and robustness. The development and validation of the method by HPLC were evaluated according to specificity, linearity, precision, accuracy and robustness. A high performance liquid chromatography from Shimadzu with Agilent® C18 column, mobile phase (water with triethylamine 1.0 % pH 5.0: acetonitrile 87:13 v/v was used in the chromatographic method. The validated microbiological and chromatographic methods were compared statistically and there was no significant difference between them when compared by Student's t-test. In the preliminary stability study, it was found stable in acid hydrolysis (0.1M) and UVA light in the period evaluated, and unstable against thermal degradation (40 and 60 °C), oxidative with hydrogen peroxide, basic in NaOH (0.1 M and 0.01M) and UVC light. Samples exposed to UVC light and thermal degradation at 60°C showed degradation kinetics following zero order and second order, respectively. The cytotoxicity assay showed no difference between the normal condition and the sample submitted to forced degradation, suggesting that the possible degradation products formed did not change the result. The methods developed did not present a significant difference, therefore, they are interchangeable, and so can be used for routine quality control analysis.

Stability-Indicating Analytical Approach for Stability Evaluation of Lactoferrin.

Lactoferrin is a multifunctional iron-binding glycoprotein in milk. Due to its potential for the treatment of various diseases, interest in products containing lactoferrin is increasing. However, as a protein, it is prone to degradation, which critically affects the quality of products. Therefore, the main purpose of our work was to develop a stability-indicating analytical approach for stability evaluation of lactoferrin. We were focused on two complementary methods: reversed-phase and size-exclusion chromatography. The stability-indicating nature of the selected methods was confirmed. They were successfully validated by following the ICH guidelines and applied to preliminary lactoferrin stability studies. Up to three degradation products, as well as aggregates and fragments of lactoferrin, were detected in various samples using complementary reversed-phase and size-exclusion chromatographic methods. The analytical approach was additionally extended with three spectroscopic techniques (absorbance, intrinsic fluorescence, and bicinchoninic acid method), which may provide valuable complementary information in some cases. The presented analytical approach allows the stability evaluation of lactoferrin in various samples, including the ability to detect differences in its degradation mechanisms. Furthermore, it has the potential to be used for the quality control of products containing lactoferrin.

Li4(OH)3Br-Based Shape Stabilized Composites for High-Temperature TES Applications: Selection of the Most Convenient Supporting Material.

Peritectic compound Li4(OH)3Br has been recently proposed as phase change material (PCM) for thermal energy storage (TES) applications at approx. 300 °C Compared to competitor PCM materials (e.g., sodium nitrate), the main assets of this compound are high volumetric latent heat storage capacity (>140 kWh/m3) and very low volume changes (<3%) during peritectic reaction and melting. The objective of the present work was to find proper supporting materials able to shape stabilize Li4(OH)3Br during the formation of the melt and after its complete melting, avoiding any leakage and thus obtaining a composite apparently always in the solid state during the charge and discharge of the TES material. Micro-nanoparticles of MgO, Fe2O3, CuO, SiO2 and Al2O3 have been considered as candidate supporting materials combined with the cold-compression route for shape-stabilized composites preparation. The work carried out allowed for the identification of the most promising composite based on MgO nanoparticles through a deep experimental analysis and characterization, including chemical compatibility tests, anti-leakage performance evaluation, structural and thermodynamic properties analysis and preliminary cycling stability study.

Alternative Silica Sources in the Synthesis of Ordered Mesoporous Silica.

In this work, the influence of the use of alternative inexpensive silica sources on the structural, morphological and textural properties of MCM-41 like mesoporous materials to be used for biomedical applications has been investigated. The Liquid Crystal Template Method has been used to prepare the ordered mesoporous structured materials according to a novel composition starting from fumed silica or granular silica gel as alternative silica sources. The obtained materials have been characterized by X-ray Powder Diffraction, Transmission and Scanning Electron Microscopy, and nitrogen sorption, which showed for both samples the formation of the ordered hexagonal pore arrangement typical of a MCM-41 material. However, when using fumed silica, higher long-range hexagonal pore ordering as well as higher surface area have been obtained (1030 vs. 763 m²/g). For comparison, the features of a commercial silica mesostructured MCM-41 type have been investigated as well. Again, the silica fumed based sample has showed higher long-range hexagonal pore ordering, higher surface area and wall thickness. Preliminary stability studies on the fumed silica based material showed a decrease in the pore ordering at the end of the third year after the synthesis.

Investigation of the physicochemical stability of emulgels composed of poloxamer 407 and different oil phases using the Quality by Design approach

Emulgels can be prepared easily and provide the efficient drug release of hydrophilic and hydrophobic drugs. In this work, emulgel systems containing poloxamer 407, Carbopol 974P® or polycarbophil, sesame oil or isopropyl myristate were prepared using Quality by Design and the physicochemical damages were investigated regarding the preliminary stability studies. The physicochemical stability was assessed according to six freeze-thaw cycles, where the appearance, phase separation (fracture), droplet size and instability index were determined. The stable formulations were further characterized by sol-gel transition temperature. The freeze-thaw cycles and analytical centrifuging showed consistent and complementary results evidencing that lower concentration of bioadhesive polymers fostered the phase separation. Formulations showed to be polydisperse systems with droplet size dependent of the freeze-thaw cycles. The stable systems were selected by Quality by Design approach, and they showed suitable gelation temperature for future pharmaceutical and biomedical applications.