New alginic acid–atenolol microparticles for inhalatory drug targeting

Chemical structure of antibiotics determines their release rate from drug-loaded poly(vinyl alcohol)/sodium sulfated alginate nanofibrous wound dressings

Antibiotics are widely used for treatment of infected wounds; however, their application through a local and controlled release system may cause more effectiveness and fewer side-effects. In this study, we fabricated drug-loaded poly(vinyl alcohol)/sodium sulfated alginate (PVA/SSA) nanofibrous mats incorporating cationic antibiotic drugs, i.e., salts of gentamicin, tetracycline, ciprofloxacin and minocycline, and examined their physicochemical and biological properties. The results of FTIR spectroscopy showed that cationic drugs have different interactions with carboxylate and sulfate functional groups of SSA depending on their chemical structure. Furthermore, the results of viscometry and conductivity analyses of the solutions revealed that the solutions with drugs with more electrical charge or/and higher functional groups resulted in a lower viscosity and conductivity compared to other drugs, due to the ability to form more hydrogen bonds. The release profiles of drug-loaded nanofibrous mats showed a burst release and then, a sustained release for 5 days, where the burst release of tetracycline (30.0 ± 0.3 %) from crosslinked mats was noticeably lower than other drugs. Biological assays confirmed the cytocompatibility, antibacterial activity and non-hemolytic behavior of all drug-loaded mats. Finally, ciprofloxacin-loaded nanofibrous mat was used as wound dressing for full-thickness wounds on rats and its efficacy was confirmed.

Polyelectrolyte Complex Dry Powder Formulations of Tobramycin with Hyaluronic Acid and Sodium Hyaluronate for Inhalation Therapy in Cystic Fibrosis-Associated Infections

Background/Objectives: Pulmonary delivered tobramycin (TOB) is a standard treatment for Pseudomonas aeruginosa lung infections, that, along with Staphylococcus aureus, is one of the most common bacteria causing recurring infections in CF patients. However, the only available formulation on the market containing tobramycin, TOBI®, is sold at a price that makes the access to the treatment difficult. Therefore, this work focuses on the development and characterization of an ionic complex between a polyelectrolyte, hyaluronic acid (HA) and its salt, sodium hyaluronate (NaHA), and TOB to be formulated as an inhalable dry powder. Methods: The solid state complex obtained by spray drying technique was physicochemically characterized by infrared spectroscopy, thermal analysis and X-ray diffraction, confirming an ionic interaction for both complexes. Results: The powder density, geometric size, and morphology along with the aerodynamic performance showed suitable properties for the powder formulations to reach the deep lung. Moisture uptake was found to be low, with the complex HA-TOB remaining physicochemically unchanged, while the NaHA-TOB required significant protection against humidity. The biopharmaceutical in vitro experiments showed a rapid dissolution which can have a positively impact in reducing side effects, while the drug release study demonstrated a reversible polyelectrolyte-drug interaction. Microbiological experiments against P. aeruginosa and S. aureus showed improved bacterial growth inhibition and bactericidal efficacy, as well as better inhibition and eradication of biofilms when compared with to TOB. Conclusions: A simple polyelectrolyte-drug complex technique represents a promising strategy for the development of antimicrobial dry powder formulations for pulmonary delivery in the treatment of cystic fibrosis (CF) lung infections.

Biopolymeric Inhalable Dry Powders for Pulmonary Drug Delivery

Natural and synthetic biopolymers are gaining popularity in the development of inhaled drug formulations. Their highly tunable properties and ability to sustain drug release allow for the incorporation of attributes not achieved in dry powder inhaler formulations composed only of micronized drugs, standard excipients, and/or carriers. There are multiple physiological barriers to the penetration of inhaled drugs to the epithelial surface, such as the periciliary layer mucus mesh, pulmonary macrophages, and inflammation and mucus compositional changes resulting from respiratory diseases. Biopolymers may facilitate transport to the epithelial surface despite such barriers. A variety of categories of biopolymers have been assessed for their potential in inhaled drug formulations throughout the research literature, ranging from natural biopolymers (e.g., chitosan, alginate, hyaluronic acid) to those synthesized in a laboratory setting (e.g., polycaprolactone, poly(lactic-co-glycolic acid)) with varying structures and compositions. To date, no biopolymers have been approved as a commercial dry powder inhaler product. However, advances may be possible in the treatment of respiratory diseases and infections upon further investigation and evaluation. Herein, this review will provide a thorough foundation of reported research utilizing biopolymers in dry powder inhaler formulations. Furthermore, insight and considerations for the future development of dry powder formulations will be proposed.

Valorization of levulinic acid by esterification with 1-octanol using a novel biocatalyst derived from Araujia sericifera

Levulinic acid, which can be obtained from biomass, has sparked great interest as a biologically-based chemical building block with wide versatility and potential. Its esterification with alcohols of different chain lengths is a promising valorization process for obtaining esters with various applications in the areas of biofuels/biolubricants, food and cosmetics, among others. In this work, the enzymatic esterification of levulinic acid and 1-octanol using a biocatalyst derived from Araujia sericifera latex was studied in systems with and without solvent. The influence of the molar ratio between alcohol and acid (ranging from 2:1-1:9), the biocatalyst loading (between 7.5 % and 17.5 % relative to the acid), the volume of n-heptane used as reaction solvent (from 0 to 4 ml), and the reaction time (6 hours) were investigated. The activity and stability of the biocatalyst in successive uses were also analyzed. A conversion of 49 % was achieved when the reaction was carried out in a solvent-free system, using an alcohol/acid molar ratio of 1:7 and after 5 h of reaction. On the other hand, the conversion was 65.1 % when the reaction was conducted in a system containing 1 ml of n-heptane as solvent, an alcohol/acid molar ratio of 1:8, and 5 h of reaction. In both cases, a temperature as low as 30 °C and an agitation speed of 300 RPM were used.

Fabrication and application of dimyristoyl phosphatidylcholine biomaterial-based nanocochleates dry powder inhaler for controlled release resveratrol delivery

Background

Resveratrol, a bioactive phytoconstituent, is used to treat chronic respiratory diseases. However, its clinical application was hampered due to its poor bioavailability. In the present study, controlled release of resveratrol loaded nanocochleate-based dry powder inhaler was investigated to improve its biopharmaceutical properties for pulmonary drug delivery. The in vivo toxicity study was performed in the healthy male albino Wistar rats by intracheal administration.

Results

Resveratrol loaded nanocochleate-based dry powder inhaler was prepared by lyophilizing the resveratrol loaded dimyristoylphosphatidylcholine sodium and calcium ion-based nanocochleates using mannitol as cryoprotectant. Resveratrol loaded nanocochleates showed a particle size and encapsulation efficiency of 329.18 ± 9.43 nm and 76.35 ± 3.65%, respectively. Resveratrol loaded nanocochleate-based dry powder exhibited a particle size of 102.21 ± 9.83 μm and satisfactory flowability with initial burst release followed by extended release up to 96 h. The in vitro drug deposition pattern using multistage cascade impactor showed 1.28-fold improvement in fine particle dose, and the in vivo toxicity potential by histopathological study in albino rats revealed safety of formulation.

Conclusions

Resveratrol loaded nanocochleate-based dry powder inhaler could serve as an efficient delivery system for the treatment of chronic respiratory diseases.

Graphical abstract

Dual Release Model to Evaluate Dissolution Profiles from Swellable Drug Polyelectrolyte Matrices

Background:

Mathematical modeling in modified drug release is an important tool that allows predicting the release rate of drugs in their surrounding environment and elucidates the transport mechanisms involved in the process.

Objective:

The aim of this work was to develop a mathematical model that allows evaluating the release profile of drugs from polymeric carriers in which the swelling phenomenon is present.

Methods:

Swellable matrices based on ionic complexes of alginic acid or carboxymethylcellulose with ciprofloxacin were prepared and the effect of adding the polymer sodium salt on the swelling process and the drug release was evaluated. Experimental data from the ciprofloxacin release profiles were mathematically adjusted, considering the mechanisms involved in each stage of the release process.

Results:

A proposed model, named “Dual Release” model, was able to properly fit the experimental data of matrices presenting the swelling phenomenon, characterized by an inflection point in their release profile. This entails applying the extended model of Korsmeyer-Peppas to estimate the percentage of drug released from the first experimental point up to the inflection point and then a model called Lumped until the final time, allowing to adequately represent the complete range of the drug release profile. Different parameters of pharmaceutical relevance were calculated using the proposed model to compare the profiles of the studied matrices.

Conclusion:

The “Dual Release” model proposed in this article can be used to predict the behavior of complex systems in which different mechanisms are involved in the release process.

Development of a Carrier-Free Dry Powder Ofloxacin Formulation With Enhanced Aerosolization Properties

Tuberculosis (TB) is a serious infectious disease that affects more than new 10 million patients each year. Many of these cases are resistant to first-line drugs so second-line ones, like fluoroquinolones, need to be incorporated into the therapeutic. Ofloxacin (OF) is a fluoroquinolone which demonstrates high antibiotic activity against the bacteria that causes TB (M. tuberculosis). In this work, ionic complexes, composed by hyaluronic acid (HA) and OF, with different neutralization degrees, were prepared and processed by spray drying (SD) to obtain powders for inhalatory administration. Combining a formulation with high neutralization degree, high SD atomization air flowrate and the use of a high-performance collection cyclone, very good process yields were obtained. Carrier-free formulations with a loading of 0.39-0.46 g_OF/g_powder showed excellent emitted, fine particle, and respirable fractions for capsule loadings of 25 and 100 mg. The ionic complexes demonstrated higher mucoadhesion than pure OF and HA. The best formulation did not affect CALU-3 cell viability up to a dose 6.5 times higher than the MIC₉₀ reported to treat multi-drug resistant TB.

Co-delivery of minocycline and paclitaxel from injectable hydrogel for treatment of spinal cord injury

Spinal cord injury (SCI) induces pathological and inflammatory responses that create an inhibitory environment at the site of trauma, resulting in axonal degeneration and functional disability. Combination therapies targeting multiple aspects of the injury, will likely be more effective than single therapies to facilitate tissue regeneration after SCI. In this study, we designed a dual-delivery system consisting of a neuroprotective drug, minocycline hydrochloride (MH), and a neuroregenerative drug, paclitaxel (PTX), to enhance tissue regeneration in a rat hemisection model of SCI. For this purpose, PTX-encapsulated poly (lactic-co-glycolic acid) PLGA microspheres along with MH were incorporated into the alginate hydrogel. A prolonged and sustained release of MH and PTX from the alginate hydrogel was obtained over eight weeks. The obtained hydrogels loaded with a combination of both drugs or each of them alone, along with the blank hydrogel (devoid of any drugs) were injected into the lesion site after SCI (at the acute phase). Histological assessments showed that the dual-drug treatment reduced inflammation after seven days. Moreover, a decrease in the scar tissue, as well as an increase in neuronal regeneration was observed after 28 days in rats treated with dual-drug delivery system. Over time, a fast and sustained functional improvement was achieved in animals that received dual-drug treatment compared with other experimental groups. This study provides a novel dual-drug delivery system that can be developed to test for a variety of SCI models or neurological disorders.

Orphan Formulations in Pediatric Schistosomiasis Treatment: Development and Characterization of Praziquantel Nanoparticle-Loaded Powders for Reconstitution

Praziquantel is a broad spectrum antihelmintic agent and represents the drug of choice for the treatment of schistosomiasis. However, its low aqueous solubility and strong bitter taste highly affect the bioavailability and compliance in pediatric patients. Thus, the purpose of this study was to develop a dry nanosuspension, by a combination of high-pressure homogenization and spray drying, intended for redispersion in a pleasant taste vehicle for extemporaneous use. Three formulations, varying stabilizers to drug ratio, were developed and characterized in terms of particle size distribution, crystallinity, morphology, in vitro dissolution, and sedimentation-redispersibility behavior. A significant reduction in particle size was achieved after the high-pressure homogenization process, and the nanoparticles were further microencapsulated by spray drying technique. The redispersed dried powders exhibited a conserved particle size distribution (in the nanometric range) and certain crystallinity extent, with satisfactory redispersion ability. Besides, the enhancement of the dissolution performance obtained after comminution was conserved, even after drying and redispersion of the extemporaneous powdered formulation. In conclusion, the developed nanoparticle-loaded powders comprise an interesting tool for the administration of praziquantel to preschool-age children.

Optimization of Ciprofloxacin Hydrochloride Spray-Dried Microparticles for Pulmonary Delivery Using Design of Experiments

Ciprofloxacin is a broad-spectrum antibiotic for treatment of pulmonary diseases such as chronic obstructive pulmonary disease and cystic fibrosis. The purpose of this work was to rationally study the spray drying of ciprofloxacin in order to identify the formulation and operating conditions that lead to a product with aerodynamic properties appropriate for dry powder inhalation. A 2^4 - 1 fractional factorial design was applied to investigate the effect of selected variables (i.e., ciprofloxacin hydrochloride (CIP) concentration, drying air inlet temperature, feed flow rate, and atomization air flow rate) on several product and process parameters (i.e., particle size, aerodynamic diameter, moisture content, densities, porosity, powder flowability, outlet temperature, and process yield) and to determine an optimal condition. The studied factors had a significant effect on the evaluated responses (higher p value 0.0017), except for the moisture content (p value > 0.05). The optimal formulation and operating conditions were as follows: CIP concentration 10 mg/mL, drying air inlet temperature 110°C, feed volumetric flow rate 3.0 mL/min, and atomization air volumetric flow rate 473 L/h. The product obtained under this set had a particle size that guarantees access to the lung, a moisture content acceptable for dry powder inhalation, fair flowability, and high process yield. The PDRX and SEM analysis of the optimal product showed a crystalline structure and round and dimpled particles. Moreover, the product was obtained by a simple and green spray drying method.

Carrier free indomethacin microparticles for dry powder inhalation

The present studies were designed to evaluate inhalatory microparticles carrying indomethacin (IN) for potential local (specific and non-specific bronchial inflammatory asthma responses) and systemic treatments (joint inflammation, rheumatoid arthritis and osteoarthritis pain) by optimizing microparticle properties, characterizing their lung deposition, drug release, evaluating cytotoxicity and also pharmacological effect in vitro. The acidic groups of IN were complexed with the cationic groups of the polyelectrolyte polylysine in order to increase the drug water compatibility. The polylysine/indomethacin ratio was fixed and the pH was adjusted in different formulations. Microparticles were obtained by spray drying using a relatively high atomization air flowrate (742 L/min) and a high-performance cyclone in order to optimize the production of microparticles with adequate attributes for inhalatory delivery. The produced microparticles exhibited high process yield and IN loading, volumetric mean diameters smaller than 5 μm and narrow particle size distributions. According to demonstrated aerosolization performance, the powders were suitable for inhalatory indomethacin local and systemic treatments. Emitted fraction was higher than 90%, the MMAD was around 3 μm and the GSD lower than 3. The respirable fraction for particles with aerodynamic diameters smaller than 5 μm was around 29% while for particles with aerodynamic diameters smaller than 3 μm the value was around 17%. The addition of lactose as carrier worsened the aerodynamic performance of the microparticles. The developed powdered systems got wet and dissolved quickly and presented higher release rates respect to pure IN in simulated lung physiological conditions. Furthermore, the assays performed in RAW 264.7 cell line showed that the microparticles exhibited the same anti-inflammatory capability as the pure drug. The developed particles did not affect the RAW 264.7 cell viability. In conclusion, a promising powder formulation for DPIs has been developed to treat, locally and systemically, inflammatory diseases.

Formulation and Characterization of Polysaccharide Microparticles for Pulmonary Delivery of Sodium Cromoglycate

Sodium cromoglycate (SC) is an antiasthmatic and antiallergenic drug commonly used for chronic inhalation therapy; however, many daily intakes are required due to the fast drug clearance from airways. For these reasons, SC polymeric particles for inhalatory administration with adequate aerosolization and mucoadhesive properties were designed to prolong the drug residence time in the site of action. Sodium carboxymethylcellulose (CMCNa), sodium hyaluronate, and sodium alginate were selected to co-process SC by spray drying. The influence of these polysaccharides on the spray drying process and powder quality was evaluated (among others, morphology, size, moisture content, hygroscopicity, flowability, densities, liquid sorption, and stability). In vitro aerosolization, drug release, and mucoadhesion performance were also studied. Particularly, a novel method to comparatively evaluate the interaction between formulations and mucin solution (mucoadhesion test) was proposed as a rapid methodology to measure adhesion properties of inhalable particles, being the results as indicative of clearance probability. Among all the studied formulations, the powder based on SC and CMCNa exhibited the best mucoadhesion and aerosolization performance, the highest process yield and adequate moisture content, hygroscopicity, and stability. SC-CMCNa formulation arose as a promising inhalatory system to reduce the daily intakes and to increase the patient compliance.