Peptide-Hitchhiking for the Development of Nanosystems in Glioblastoma.

Glioblastoma (GBM) remains the epitome of aggressiveness and lethality in the spectrum of brain tumors, primarily due to the blood-brain barrier (BBB) that hinders effective treatment delivery, tumor heterogeneity, and the presence of treatment-resistant stem cells that contribute to tumor recurrence. Nanoparticles (NPs) have been used to overcome these obstacles by attaching targeting ligands to enhance therapeutic efficacy. Among these ligands, peptides stand out due to their ease of synthesis and high selectivity. This article aims to review single and multiligand strategies critically. In addition, it highlights other strategies that integrate the effects of external stimuli, biomimetic approaches, and chemical approaches as nanocatalytic medicine, revealing their significant potential in treating GBM with peptide-functionalized NPs. Alternative routes of parenteral administration, specifically nose-to-brain delivery and local treatment within the resected tumor cavity, are also discussed. Finally, an overview of the significant obstacles and potential strategies to overcome them are discussed to provide a perspective on this promising field of GBM therapy.

Organ-on-a-Chip: Ubi sumus? Fundamentals and Design Aspects.

This review outlines the evolutionary journey from traditional two-dimensional (2D) cell culture to the revolutionary field of organ-on-a-chip technology. Organ-on-a-chip technology integrates microfluidic systems to mimic the complex physiological environments of human organs, surpassing the limitations of conventional 2D cultures. This evolution has opened new possibilities for understanding cell-cell interactions, cellular responses, drug screening, and disease modeling. However, the design and manufacture of microchips significantly influence their functionality, reliability, and applicability to different biomedical applications. Therefore, it is important to carefully consider design parameters, including the number of channels (single, double, or multi-channels), the channel shape, and the biological context. Simultaneously, the selection of appropriate materials compatible with the cells and fabrication methods optimize the chips' capabilities for specific applications, mitigating some disadvantages associated with these systems. Furthermore, the success of organ-on-a-chip platforms greatly depends on the careful selection and utilization of cell resources. Advances in stem cell technology and tissue engineering have contributed to the availability of diverse cell sources, facilitating the development of more accurate and reliable organ-on-a-chip models. In conclusion, a holistic perspective of in vitro cellular modeling is provided, highlighting the integration of microfluidic technology and meticulous chip design, which play a pivotal role in replicating organ-specific microenvironments. At the same time, the sensible use of cell resources ensures the fidelity and applicability of these innovative platforms in several biomedical applications.

A Regulatory Perspective on Biosimilar Medicines.

By definition, biosimilar medicinal products are biological medicinal products that are similar to other biological medicinal products that are already on the market-the reference medicinal products. Access to biosimilar medicines is a current reality. However, to achieve this goal, it is extremely important to consistently and scientifically substantiate the regulatory requirements necessary for biosimilar medicines when accessing the market. Based on an analysis of the raw materials and the type of methods used in the manufacturing processes of biological medicines, it is known that this tends to be more complex for the quality of the finished product than the manufacture of molecules obtained through a chemical process. It is then relevant to highlight the main differences between both products: biological medicines manufactured using biotechnology and the current generics containing active pharmaceutical ingredients (APIs) obtained from synthetic processes. Once arriving at the approval process of these medicinal products, it is imperative to analyse the guidance documents and the regulatory framework that create the rules that allow these biosimilar medicinal products to come to the market. The present review aimed at documenting comparatively the specific provisions of European legislation, through the European Medicines Agency (EMA), as well as the legislation of the United States of America, through the Food and Drug Administration (FDA). This was then translated into a critical appraisal of what concerns the specific criteria that determine the favourable evaluation of a biosimilar when an application for marketing authorisation is submitted to different regulatory agencies. The gathered evidence suggests that the key to the success of biosimilar medicines lies in a more rigorous and universal regulation as well as a greater knowledge, acceptance, and awareness of health professionals to enable more patients to be treated with biological strategies at an earlier stage of the disease and with more affordable medicines, ensuring always the safety and efficacy of those medicines.

Fortified chocolate mousse with powder and extract from Moringa oleifera leaves for nutritional value improvement.

This study focuses on the characterisation and incorporation of Moringa oleifera leaf powder (MOP) from Luanda (Angola) and its extract (MOE) in fortified chocolate mousse. Dark green (DG) leaves presented superior nutritional values compared to other leaves. DG contained a higher concentration of mineral salts (10 ± 1 mg/100 g of dry leaves), phenolic compounds (267 ± 4 mg GAE/g), vitamins (1.9 ± 0.2 mg/g of dry extract) and strong antioxidant capacity (IC50, 115 ± 8 µg/mL). Therefore, DG leaves were used to fortify the chocolate mousse. The leaves were prepared in three samples: control, 2 % MOP (w/w) and 2 % MOE (v/v). Textural and rheological analysis of chocolate mousse samples revealed a pseudoplastic profile for all samples, with decreased texture attributes and viscosity due to the incorporation. The sensory evaluation demonstrated that MOP and MOE samples presented 93 % and 88 % resemblance to the original product regarding general acceptance, respectively.

Safe-by-design development of a topical patch for drug delivery

Few topical products have been developed specifically to treat acute and chronic arthritis and inflammation, using non-steroidal anti-inflammatory drugs (NSAIDs). The lack of dosing accuracy commonly found in locally applied semisolid products for cutaneous use is a critical issue that leads to treatment failure. The aim of the present work is to develop a differentiated and innovative topical patch based on a monolithic hydrogel for ibuprofen skin delivery, in order to provide a safer and accurate way of drug administration along with improved treatment compliance. Topical patches based on hydroxypropylmethylcellulose (HPMC) were optimized in composition, in terms of enhancer and adhesive, supported on a systematic assessment of in vitro release and permeation behavior and adhesion properties. Several mathematical models were used to scrutinize the release mechanisms from the patches. In vitro release kinetics was shown to be mainly driven by diffusion. However, other mechanisms seemed to be also present, supporting the feasibility of using patches for sustained drug delivery. PEG 200 provided the best permeation rate, with a permeation enhancement ratio of ca. 3 times higher, than the commercial reference. The addition of Eudragit L30D 55 to the formulation led to the best adhesion profile, thus achieving a successful development based on a safe-by-design concept.

Development of levofloxacin-loaded PLGA microspheres of suitable properties for sustained pulmonary release.

Aerosol antibiotics are an interesting alternative to oral or intravenous therapy in Cystic Fibrosis lung infections. Levofloxacin (LVX) inhaled solution is already an effective option. In this study, the aim was the development of LVX-loaded PLGA microspheres (MS) for pulmonary administration as a dry powder. MS were prepared, for the first time, by a modified double emulsion solvent evaporation method with premix membrane homogenization. Aqueous phases were saturated with LVX and a fatty acid (lauric acid) was added to avoid the drug escaping from the organic phase. MS were characterized in terms of size, drug content, morphology and in vitro release properties. X-ray diffraction, Fourier-transform infrared spectroscopy, differential and gravimetric thermal analysis, and cytotoxicity analyses were performed. Results showed this new method increased the drug loading while maintaining an adequate (∼5 µm) particle size and controlled release. Compared to a solution for inhalation, these properties combined with the dry-powder nature of these MS will improve patient compliance. The incorporation of lauric acid was not advantageous because the particle size was higher and no improvements concerning the sustained release occurred. LVX was molecularly dispersed in the matrix, or it was in amorphous state, as confirmed by the physico-chemical analyses. Calu-3 cell viability assays demonstrated no cytotoxicity for these MS, making them a promising system for LVX pulmonary delivery.

Modeling of ultra-small lipid nanoparticle surface charge for targeting glioblastoma.

Surface modification of ultra-small nanostructured lipid carriers (usNLC) via introduction of a positive charge is hypothesized to prompt site-specific drug delivery for glioblastoma multiforme (GBM) treatment. A more effective interaction with negatively charged lipid bilayers, including the blood-brain barrier (BBB), will facilitate the nanoparticle access to the brain. For this purpose, usNLC with a particle size of 43.82 ±â€¯0.03 nm and a polydispersity index of 0.224 were developed following a Quality by Design approach. Monomeric and gemini surfactants, either with conventional headgroups or serine-based ones, were tested for the surface modification, and the respective safety and efficacy to target GBM evaluated. A comprehensive in silico-in vitro approach is also provided based on molecular dynamics simulations and cytotoxicity studies. Overall, monomeric serine-derived surfactants displayed the best performance, considering altogether particle size, zeta potential, cytotoxic profile and cell uptake. Although conventional surfactants were able to produce usNLC with suitable physicochemical properties and cell uptake, their use is discouraged due to their high cytotoxicity. This study suggests that monomeric serine-derived surfactants are promising agents for developing nanosystems aiming at brain drug delivery.

Pulmonary pharmacokinetics of levofloxacin in rats after aerosolization of immediate-release chitosan or sustained-release PLGA microspheres.

A comparative pharmacokinetic study was conducted in rats after intratracheal aerosolization of levofloxacin, as a solution, as immediate-release chitosan microspheres or as sustained-release PLGA microspheres. A pharmacokinetic model was constructed to model levofloxacin concentrations both in plasma and in the lung epithelial lining fluid (ELF). The plasma and ELF experimental concentration profiles versus time were similar for the intravenous and intratracheal levofloxacin solutions and for the intratracheal levofloxacin-loaded chitosan microsphere dry powder, indicating that levofloxacin diffused almost instantaneously through the broncho-alveolar barrier and that the chitosan microspheres released levofloxacin very rapidly, as anticipated from in vitro release studies. The bioavailability for the intratracheal levofloxacin solution and intratracheal chitosan microspheres was estimated to be 98% and 71%, respectively, both with a direct release into the ELF compartment. The ELF-to-unbound plasma AUC ratios were slightly above 2 and may result from an efflux transport. For the intratracheal PLGA microspheres, a high ELF-to-unbound plasma AUC concentration ratio (311) was observed and high levofloxacin concentrations were maintained in ELF for at least 72h in consistency with the in vitro release studies. The bioavailability was 92%, with 19% of the dose released immediately (burst release) into the ELF and 73% released slowly into the ELF from a depot compartment, i.e. the PLGA microspheres, according to a Weibull model. These results highlight the benefit of using sustained-release microspheres administered as aerosols to provide and to maintain high pulmonary concentrations of an antibiotic characterized with a high permeability profile through the broncho-alveolar barrier. The sustained-release microsphere dry powder aerosol may therefore provide advantages over solutions or pure drug dry powders for inhalation in terms of treatment efficiency, ease of use and frequency of administration.

Optimization of levofloxacin-loaded crosslinked chitosan microspheres for inhaled aerosol therapy.

The aim of this work was the development of innovative levofloxacin-loaded swellable microspheres (MS) for the dry aerosol therapy of pulmonary chronicPseudomonas aeruginosainfections in Cystic Fibrosis patients. In a first step, a factorial design was applied to optimize formulations of chitosan-based MS with glutaraldehyde as crosslinker. After optimization, other crosslinkers (genipin, glutaric acid and glyceraldehyde) were tested. Analyses of MS included aerodynamic and swelling properties, morphology, drug loading, thermal and chemical characteristics,in vitroantibacterial activity and drug release studies. The prepared MS presented a drug content ranging from 39.8% to 50.8% of levofloxacin in an amorphous or dispersed state, antibacterial activity and fast release profiles. The highest degree of swelling was obtained for MS crosslinked with glutaric acid and genipin. These formulations also presented satisfactory aerodynamic properties, making them a promising alternative, in dry-powder inhalers, to levofloxacin solution for inhalation.

Generation of hydrate forms of paroxetine HCl from the amorphous state: an evaluation of thermodynamic and experimental predictive approaches.

In this study, we evaluate the use of theoretical thermodynamic analysis of amorphous paroxetine hydrochloride (HCl) as well as experimental assessment in order to identify the most promising approach to stability and dissolution behaviour prediction, particularly in relation to stoichiometric and nonstoichiometric hydrate formation. Differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared and X-ray diffraction techniques were used. Parameters including heat capacity, configurational thermodynamic quantities, fragility and relaxation time classified amorphous paroxetine HCl as a moderate fragile glass with a considerable degree of molecular mobility. Solubility studies indicated little advantage of the amorphous form over the crystalline due to conversion to the hydrate Form I during equilibration, while the dissolution rate was higher for the amorphous form under sink conditions. A marked difference in the physical stability of amorphous paroxetine HCl was observed between dry and low humidity storage, with the system recrystallizing to the hydrate form. We conclude that, in this particular case (amorphous conversion to the hydrate), water may be playing a dual role in both plasticizing the amorphous form and driving the equilibrium towards the hydrate form, hence prediction of recrystallization behaviour from amorphous characteristics may be confounded by the additional process of hydrate generation.

The influence of drug physical state on the dissolution enhancement of solid dispersions prepared via hot-melt extrusion: a case study using olanzapine.

In this study, we examine the relationship between the physical structure and dissolution behavior of olanzapine (OLZ) prepared via hot-melt extrusion in three polymers [polyvinylpyrrolidone (PVP) K30, polyvinylpyrrolidone-co-vinyl acetate (PVPVA) 6:4, and Soluplus® (SLP)]. In particular, we examine whether full amorphicity is necessary to achieve a favorable dissolution profile. Drug­polymer miscibility was estimated using melting point depression and Hansen solubility parameters. Solid dispersions were characterized using differential scanning calorimetry, X-ray powder diffraction, and scanning electron microscopy. All the polymers were found to be miscible with OLZ in a decreasing order of PVP>PVPVA>SLP. At a lower extrusion temperature (160°C), PVP generated fully amorphous dispersions with OLZ, whereas the formulations with PVPVA and SLP contained 14%-16% crystalline OLZ. Increasing the extrusion temperature to 180°C allowed the preparation of fully amorphous systems with PVPVA and SLP. Despite these differences, the dissolution rates of these preparations were comparable, with PVP showing a lower release rate despite being fully amorphous. These findings suggested that, at least in the particular case of OLZ, the absence of crystalline material may not be critical to the dissolution performance. We suggest alternative key factors determining dissolution, particularly the dissolution behavior of the polymers themselves.

Structure activity relationships in alkylammonium C12-gemini surfactants used as dermal permeation enhancers.

The purpose of this study was to determine the ability and the safety of a series of alkylammonium C12-gemini surfactants to act as permeation enhancers for three model drugs, namely lidocaine HCl, caffeine, and ketoprofen. In vitro permeation studies across dermatomed porcine skin were performed over 24 h, after pretreating the skin for 1 h with an enhancer solution 0.16 M dissolved in propylene glycol. The highest enhancement ratio (enhancement ratio (ER)=5.1) was obtained using G12-6-12, resulting in a cumulative amount of permeated lidocaine HCl of 156.5 µg cm−2. The studies with caffeine and ketoprofen revealed that the most effective gemini surfactant was the one with the shorter spacer, G12-2-12. The use of the latter resulted in an ER of 2.4 and 2.2 in the passive permeation of caffeine and ketoprofen, respectively. However, Azone was found to be the most effective permeation enhancer for ketoprofen, attaining a total of 138.4 µg cm−2 permeated, 2.7-fold over controls. This work demonstrates that gemini surfactants are effective in terms of increasing the permeation of drugs, especially in the case of hydrophilic ionized compounds, that do not easily cross the stratum corneum. Skin integrity evaluation studies did not indicate the existence of relevant changes in the skin structure after the use of the permeation enhancers, while the cytotoxicity studies allowed establishing a relative cytotoxicity profile including this class of compounds, single chain surfactants, and Azone. A dependence of the toxicity to HEK and to HDF cell lines on the spacer length of the various gemini molecules was found.

Identification and characterization of stoichiometric and nonstoichiometric hydrate forms of paroxetine HCl: reversible changes in crystal dimensions as a function of water absorption.

Paroxetine hydrochloride (HCl) is an antidepressant drug, reported to exist in the anhydrous form (form II) and as a stable hemihydrate (form I). In this study, we investigate the hydration behavior of paroxetine HCl form II with a view to understanding both the nature of the interaction with water and the interchange between forms II and I as a function of both temperature and water content. In particular, we present new evidence for both the structure and the interconversion process to be more complex than previously recognized. A combination of characterization techniques was used, including thermal (differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)), spectroscopic (attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR)), dynamic vapor sorption (DVS) and X-ray powder diffraction (XRPD) with variable humidity, along with computational molecular modeling of the crystal structures. The total amount of water present in form II was surprisingly high (3.8% w/w, 0.8 mol of water/mol of drug), with conversion to the hemihydrate noted on heating in hermetically sealed DSC pans. XRPD, supported by ATR-FTIR and DVS, indicated changes in the unit cell dimensions as a function of water content, with clear evidence for reversible expansion and contraction as a function of relative humidity (RH). Based on these data, we suggest that paroxetine HCl form II is not an anhydrate but rather a nonstoichiometric hydrate. However, no continuous channels are present and, according to molecular modeling simulation, the water is moderately strongly bonded to the crystal, which is in itself an uncommon feature when referring to nonstoichiometric hydrates. Overall, therefore, we suggest that the anhydrous form of paroxetine HCl is not only a nonstoichiometric hydrate but also one that shows highly unusual characteristics in terms of gradual unit cell expansion and contraction despite the absence of continuous channels. These structural features in turn influence the tendency of this drug to convert to the more stable hemihydrate. The study has implications for the recognition and understanding of the behavior of pharmaceutical nonstoichiometric hydrates.

A combination of nonionic surfactants and iontophoresis to enhance the transdermal drug delivery of ondansetron HCl and diltiazem HCl.

The present work reports the evaluation of three nonionic ether-monohydroxyl surfactants (C(12)E(1), C(12)E(5,) and C(12)E(8)) as skin permeation enhancers in the transdermal drug delivery of two drugs: ondansetron hydrochloride and diltiazem hydrochloride, formulated as hydrogels. The enhancers are used alone, or in combination with iontophoresis (0.3 mA - 8h). After 1h of pre-treatment with 0.16 M enhancer solutions in propylene glycol (PG), passive and iontophoretic 24 h in vitro studies across dermatomed porcine skin were performed using vertical Franz diffusion cells. Data obtained showed that the nonionic surfactant C(12)E(5) was the most effective permeation enhancer, both for the passive process as well as for samples subjected to iontophoresis, resulting in cumulative amounts of ondansetron HCl after 24h of approximately 93 µg/cm(2) and 336 µg/cm(2), respectively. Data obtained using diltiazem HCl showed a similar trend. The use of the nonionic surfactant C(12)E(5) resulted in higher enhancement ratios (ER) in passive studies, but C(12)E(8) yielded slightly higher values of drug permeated (2678 µg/cm(2)) than C(12)E(5) (2530 µg/cm(2)) when iontophoresis was also employed. Skin integrity studies were performed to assess potential harmful effects on the tissues resulting from the compounds applied and/or from the methodology employed. Skin samples used in permeation studies visualized by light microscopy and Scanning Electron Microscopy (SEM) at different levels of magnification did not show significant morphological and structural changes, when compared to untreated samples. Complementary studies were performed to gain information regarding the relative cytotoxicity of the penetration enhancers on skin cells. MTS assay data using human epidermal keratinocytes (HEK) and human dermal fibroblasts (HDF) indicated that HEK are more sensitive to the presence of the enhancers than HDF and that the toxicity of these compounds is enhancer molecular weight dependent.

The size of solid lipid nanoparticles: an interpretation from experimental design.

This study aimed to investigate the role of different factors affecting the size of solid lipid nanoparticles (SLN), prepared by the emulsification-solvent evaporation method. A double factorial design was conducted so as to cover a wide range of sizes, highlighting zones with different behaviour with respect to changes in the controlled variables: lipid concentration, solvent:lipid ratio and emulsifier concentration. The solvent:lipid ratio constituted the main factor influencing particle size. Increasing the amount of solvent induced a decrease in the size. This was a general trend, essentially independent from solvent and lipid type. The amount of emulsifier had a non-trivial impact on size, depending on whether systems were located below, above or close to the optimal surface coverage. The amount of lipid had a limited influence upon particle size, being more relevant for lower lipid concentrations. An optimal formulation was selected for intermediate levels of the three variables. Sonication reduced both particle size and polydispersity. These particles were also tested as drug carriers using simvastatin as a model of lipophilic drug. SLN were able to entrap a high amount of simvastatin, with little effect upon size and zeta potential, constituting a promising carrier for lipophilic drugs.

Aggregation and gelation in hydroxypropylmethyl cellulose aqueous solutions.

In this work we present an analysis of the thermal behavior of hydroxypropylmethyl cellulose aqueous solutions, from room temperature to higher temperatures, above gelation. We focus on significant aspects, essentially overlooked in previous work, such as the correlation between polymer hydrophobicity and rheological behavior, and the shear effect on thermal gelation. Micropolarity and aggregation of the polymer chains were monitored by both UV/vis and fluorescence spectroscopic techniques, along with polarized light microscopy. Gel formation upon heating was investigated using rheological experiments, with both large strain (rotational) tests at different shear rates and small strain (oscillatory) tests. The present observations allow us to compose a picture of the evolution of the system upon heating: firstly, polymer reptation increases due to thermal motion, which leads to a weaker network. Secondly, above 55 degrees C, the polymer chains become more hydrophobic and polymer clusters start to form. Finally, the number of physical crosslinks between polymer clusters and the respective lifetimes increase and a three-dimensional network is formed. This network is drastically affected if higher shear rates, at non-Newtonian regimes, are applied to the system.

Mucoadhesion and the gastrointestinal tract.

The concept of mucoadhesion is one that has the potential to improve the highly variable residence times experienced by drugs and dosage forms at various sites in the gastrointestinal tract, and consequently, to reduce variability and improve efficacy. Intimate contact with the mucosa should enhance absorption or improve topical therapy. A variety of approaches have been investigated for mucoadhesion in the gastrointestinal tract, particularly for the stomach and small intestine. Despite interesting results in these sites, mucoadhesive approaches have not yet shown success in humans. The potential of the lower gut for these applications has been largely neglected, although the large intestine in particular may benefit, and the colon has several factors that suggest mucoadhesion could be successful there, including lower motility and the possibility of a lower mucus turnover and thicker mucus layer. In vitro studies on colonic mucoadhesion show promise, and rectal administration has shown some positive results in vivo. This review considers the background to mucoadhesion with respect to the physiological conditions of the gastrointestinal tract as well as the principles that underlie this concept. Mucoadhesive approaches to gastrointestinal drug delivery will be examined, with particular attention given to the lower gut.

Drug transport in responding lipid membranes can be regulated by an external osmotic gradient.

In this paper, we demonstrate, for the first time, how an external osmotic gradient can be used to regulate diffusion of solutes across a lipid membrane. We present experimental and theoretical studies of the transport of different solutes across a monoolein membrane in the presence of an external osmotic gradient. The osmotic gradient introduces phase transformations in the membrane, and it causes nonlinear transport behavior. The external gradient can thus act as a kind of switch for diffusive transport in the skin and in controlled release drug formulations.

Compaction, compression and drug release properties of diclofenac sodium and ibuprofen pellets comprising xanthan gum as a sustained release agent.

Compaction and compression of xanthan gum pellets were evaluated and drug release from tablets made of pellets was characterised. Two types of pellets were prepared by extrusion-spheronisation. Formulations included xanthan gum, at 16% (w/w), diclofenac sodium or ibuprofen, at 10% (w/w), among other excipients. An amount of 500 mg of pellets fraction 1000-1400 microm were compacted in a single punch press at maximum punch pressure of 125 MPa using flat-faced punches (diameter of 1.00 cm). Physical properties of pellets and tablets were analysed. Laser profilometry analysis and scanning electron microscopy of the upper surface and the surface of fracture of tablets revealed that particles remained as coherent individual units after compression process. Pellets were flatted in the same direction of the applied stress evidencing a lost of the original curvature of the spherical unit. Pellets showed close compressibility degrees (49.9% for pellets comprising diclofenac sodium and 48.5% for pellets comprising ibuprofen). Xanthan gum pellets comprising diclofenac sodium experienced a reduction of 65.5% of their original sphericity while those comprising ibuprofen lost 49.6% of the original porosity. Permanent deformation and densification were the relevant mechanisms of compression. Fragmentation was regarded as non-existent. The release of the model drug from both type of tablets revealed different behaviours. Tablets made of pellets comprising ibuprofen released the model drug in a bimodal fashion and the release behaviour was characterised as Case II transport mechanism (release exponent of 0.93). On the other hand, the release behaviour of diclofenac sodium from tablets made of pellets was anomalous (release exponent of 0.70). For the latter case, drug diffusion and erosion were competing mechanisms of drug release.