Preparation and physicochemical characterization of spray-dried and jet-milled microparticles containing bosentan hydrate for dry powder inhalation aerosols

Evaluating the effect of sodium alginate and sodium carboxymethylcellulose on pulmonary delivery of levofloxacin spray-dried microparticles

BACKGROUND

Patients with cystic fibrosis commonly suffer from lung infections caused by Pseudomonas aeruginosa. Recently, the Levofloxacin (LVF) nebulizing solution (Quinsair®) has been prescribed for the antimicrobial management. The sustained-release (SR) dry powder formulation of LVF is a convenient alternative to Quinsair®. It has the potential to enhance patient convenience and decrease the likelihood of drug resistance over time.

OBJECTIVE

In this paper, we set forth to formulate and evaluate the potential application of sodium alginate (SA) and sodium carboxymethylcellulose (SCMC) for sustained pulmonary delivery of LVF.

METHODS

The spray-dried (SD) LVF microparticles were formulated using SCMC and SA along with L-leucine (Leu). The microparticles were analyzed in terms of particle size, morphology, x-ray diffraction (XRD), in-vitro drug release, and aerodynamic properties. Selected formulations were further proceeded to short-term stability test.

RESULTS

The polymer-containing samples displayed process yield of 33.31%-39.67%, mean entrapment efficiency of 89% and volume size within the range of 2-5 μm. All the hydrogel microparticles were amorphous and exhibited rounded morphology with surface indentations. Formulations with a drug-to-excipient ratio of 50:50 and higher, showed a 24-h SR. The aerodynamic parameters were fine particle fraction and emitted dose percentage ranging between 46.21%-60.6% and 66.67%-87.75%, respectively. The short-term stability test revealed that the formulation with a 50:50 drug-to-excipient ratio, containing SA, demonstrated better physical stability.

CONCLUSION

The selected formulation containing SA has the potential to extend the release duration. However, further enhancements are required to optimize its performance.

Preparation of orodispersible tablets of bosentan using xylitol and menthol as dissolution enhancers

Bosentan is a drug used to treat pulmonary hypertension via dual endothelial receptor antagonism. Bosentan has a restricted oral bioavailability, a problem that's mostly due to poor solubility and hepatic metabolism. It is extensively used for the elderly and children who require a friendly dosage form like orodispersible tablets. So, the goal of this research work was to hasten the dissolution rate of bosentan to produce an orodispersible tablet with immediate drug release. Bosentan was exposed to ethanol-assisted kneading with a rise of xylitol or menthol concentrations (1:1 and 1:2 molar ratio of bosentan with excipient). In addition to observing the dissolution behavior, the resulting dry products were investigated using Fourier transform infrared spectroscopy (FTIR), differential thermal analysis (DTA), and X-ray diffraction (XRD). The FTIR reflected possible hydrogen bonding with xylitol and menthol. DSC studies reflected a reduction in the enthalpy and Tm. These results with XRD data reflected partial co-amorphization in the case of xylitol and eutaxia in the case of menthol. These modifications were related to an accelerated dissolving rate. The developed systems were fabricated as orodispersible tablets which exhibited immediate release of bosentan. Thus, the current study offered simple co-processing for the preparation of orodispersible bosentan tablets.

Advancements in the Design and Development of Dry Powder Inhalers and Potential Implications for Generic Development

Dry powder inhalers (DPIs) are drug-device combination products where the complexity of the formulation, its interaction with the device, and input from users play important roles in the drug delivery. As the landscape of DPI products advances with new powder formulations and novel device designs, understanding how these advancements impact performance can aid in developing generics that are therapeutically equivalent to the reference listed drug (RLD) products. This review details the current understanding of the formulation and device related principles driving DPI performance, past and present research efforts to characterize these performance factors, and the implications that advances in formulation and device design may present for evaluating bioequivalence (BE) for generic development.

A facile one-step jet-millingapproach for the preparation of proliposomal dry powder for inhalationaseffective delivery system for anti-TBtherapeutics

Objective: Physicochemical characterization and assessmentof aerosol dispersion performance of anti-TB proliposome dry powders for inhalation (DPIs) prepared using a single-step jet-milling (JM) approach. Significance: Conventional tuberculosis treatment involves isoniazid and rifampicin as first-line agents in extended oral multi-drug regimes. Liposomal DPIs are emerging as promising alternatives for targeted delivery of anti-TB agents to alveolar macrophages harboring Mycobacterium tuberculosis. However, traditional approaches for liposomal DPI preparation are tedious, time consuming and require sophisticated/expensive equipment. The proposed JM technique for preparation of proliposome DPIs could obviate these limitations and facilitate use of these drugs for more effective and safer treatment. Methods: Proliposome DPIs containing isoniazid and/or rifampicin, cholesterol and cholesterol sulfate were successfully prepared via JM (injection pressure, 7.4 bar; milling pressure, 3.68 bar). Their physicochemical, content uniformity, and in vitro aerosol dispersion performance were assessed using scanning electron microscopy/energy-dispersive X-ray spectroscopy, transmission electron microscopy, dynamic light scattering/Zeta potential, X-ray diffraction spectroscopy, thermogravimetric analysis, high performance liquid chromatography, and the Next Generation Impactor. Results: The DPIs exhibited consistent, spherically shaped, smooth particles. Drug particles were evenly distributed with acceptable content uniformity. Drug crystallinity was not significantly affected by milling and the formulations had minimal (<2.0%) water content. After reconstitution of theDPIs, the hydrodynamic size was about 370.9 - 556.2nm and charge was-12.3 - -47.3mV. Furthermore, the proliposome DPIs presented emitted dose (69.04 - 89.03%), fine particle fraction,< 4.4 µm (13.7 - 57.8%), and mass median aerodynamic diameter (<3.0 µm), which satisfied the requirements for deep lung delivery. Conclusion: The proposed approach was suitable for preparation of proliposome DPIs that could be deployed for local targeting of the lower respiratory tract for treatment of tuberculosis.

Polymeric Microparticles: Synthesis, Characterization and In Vitro Evaluation for Pulmonary Delivery of Rifampicin

Rifampicin, a potent broad-spectrum antibiotic, remains the backbone of anti-tubercular therapy. However, it can cause severe hepatotoxicity when given orally. To overcome the limitations of the current oral therapy, this study designed inhalable spray-dried, rifampicin-loaded microparticles using aloe vera powder as an immune modulator, with varying concentrations of alginate and L-leucine. The microparticles were assessed for their physicochemical properties, in vitro drug release and aerodynamic behavior. The spray-dried powders were 2 to 4 µm in size with a percentage yield of 45 to 65%. The particles were nearly spherical with the tendency of agglomeration as depicted from Carr’s index (37 to 65) and Hausner’s ratios (>1.50). The drug content ranged from 0.24 to 0.39 mg/mg, with an association efficiency of 39.28 to 96.15%. The dissolution data depicts that the in vitro release of rifampicin from microparticles was significantly retarded with a higher L-leucine concentration in comparison to those formulations containing a higher sodium alginate concentration due to its hydrophobic nature. The aerodynamic data depicts that 60 to 70% of the aerosol mass was emitted from an inhaler with MMAD values of 1.44 to 1.60 µm and FPF of 43.22 to 55.70%. The higher FPF values with retarded in vitro release could allow sufficient time for the phagocytosis of synthesized microparticles by alveolar macrophages, thereby leading to the eradication of M. tuberculosis from these cells.

Studies on the Vitrified and Cryomilled Bosentan

In this paper, several experimental techniques [X-ray diffraction, differential scanning calorimetry (DSC), thermogravimetry, Fourier transform infrared spectroscopy, and broad-band dielectric spectroscopy] have been applied to characterize the structural and thermal properties, H-bonding pattern, and molecular dynamics of amorphous bosentan (BOS) obtained by vitrification and cryomilling of the monohydrate crystalline form of this drug. Samples prepared by these two methods were found to be similar with regard to their internal structure, H-bonding scheme, and structural (α) dynamics in the supercooled liquid state. However, based on the analysis of α-relaxation times (dielectric measurements) predicted for temperatures below the glass-transition temperature (T_g), as well as DSC thermograms, it was concluded that the cryoground sample is more aged (and probably more physically stable) compared to the vitrified one. Interestingly, such differences in physical properties turned out to be reflected in the lower intrinsic dissolution rate of BOS obtained by cryomilling (in the first 15 min of dissolution test) in comparison to the vitrified drug. Furthermore, we showed that cryogrinding of the crystalline BOS monohydrate leads to the formation of a nearly anhydrous amorphous sample. This finding, different from that reported by Megarry et al. [Carbohydr. Res.2011, 346, 1061−106421492830] for trehalose (TRE), was revealed on the basis of infrared and thermal measurements. Finally, two various hypotheses explaining water removal upon cryomilling have been discussed in the manuscript.

Preparation and In Vivo Evaluation of a Lidocaine Self-Nanoemulsifying Ointment with Glycerol Monostearate for Local Delivery

Lidocaine, a commonly used local anesthetic, has recently been developed into a number of ointment products to treat hemorrhoids. This study examined its efficient delivery to the dermis through the pharmaceutical improvement of hemorrhoid treatment ointments. We attempted to increase the amount of skin deposition of lidocaine by forming a nanoemulsion through the self-nanoemulsifying effect that occurs when glycerol monostearate (GMS) is saturated with water. Using Raman mapping, the depth of penetration of lidocaine was visualized and confirmed, and the local anesthetic effect was evaluated via an in vivo tail-flick test. Evaluation of the physicochemical properties confirmed that lidocaine was amorphous and evenly dispersed in the ointment. The in vitro dissolution test confirmed that the nanoemulsifying effect of GMS accelerated the release of the drug from the ointment. At a specific concentration of GMS, lidocaine penetrated deeper into the dermis; the in vitro permeation test showed similar results. When compared with reference product A in the tail-flick test, the L5 and L6 compounds containing GMS had a significantly higher anesthetic effect. Altogether, the self-nanoemulsifying effect of GMS accelerated the release of lidocaine from the ointment. The compound with 5% GMS, the lowest concentration that saturated the dermis, was deemed most appropriate.

Engineered mucoadhesive microparticles of formoterol/budesonide for pulmonary administration

In the present study, a multi-component system comprised of dipalmitylphospatidylcholine (DPPC), Chitosan, Lactose, and L-Leucine was developed for pulmonary delivery. Microparticles were engineered by the spray drying process and the selection of the critical parameters was performed by applying experimental design. The microcarriers with the appropriate size and yield were co-formulated with two active pharmaceutical ingredients (APIs), namely, Formoterol fumarate and Budesonide, and they were further investigated. All formulations exhibited spherical shape, appropriate aerodynamic performance, satisfying entrapment efficiency, and drug load. Their physicochemical properties were evaluated using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and Differential Scanning Calorimetry (DSC). The aerodynamic particle size characterization was determined using an eight-stage Andersen cascade impactor, whereas the release of the actives was monitored in vitro in simulated lung fluid. Additional evaluation of the microparticles' mucoadhesive properties was performed by ζ-potential measurements and ex vivo mucoadhesion study applying a falling liquid film method using porcine lung tissue. Cytotoxicity and cellular uptake studies in Calu-3 lung epithelial cell line were conducted to further investigate the safety and efficacy of the developed formulations.

Design and Comprehensive Characterization of Tetramethylpyrazine (TMP) for Targeted Lung Delivery as Inhalation Aerosols in Pulmonary Hypertension (PH): In Vitro Human Lung Cell Culture and In Vivo Efficacy

This is the first study reporting on the design and development innovative inhaled formulations of the novel natural product antioxidant therapeutic, tetramethylpyrazine (TMP), also known as ligustrazine. TMP is obtained from Chinese herbs belonging to the class of Ligusticum. It is known to have antioxidant properties. It can act as a Nrf2/ARE activator and a Rho/ROCK inhibitor. The present study reports for the first time on the comprehensive characterization of raw TMP (non-spray dried) and spray dried TMP in a systematic manner using thermal analysis, electron microscopy, optical microscopy, and Raman spectroscopy. The in vitro aerosol dispersion performance of spray dried TMP was tested using three different FDA-approved unit-dose capsule-based human dry powder inhaler devices. In vitro human cellular studies were conducted on pulmonary cells from different regions of the human lung to examine the biocompatibility and non-cytotoxicity of TMP. Furthermore, the efficacy of inhaled TMP as both liquid and dry powder inhalation aerosols was tested in vivo using the monocrotaline (MCT)-induced PH rat model.

Therapeutic peptides for the treatment of cystic fibrosis: Challenges and perspectives

Cystic fibrosis (CF) is the most common amongst rare genetic diseases, affecting more than 70.000 people worldwide. CF is characterized by a dysfunctional chloride channel, termed cystic fibrosis conductance regulator (CFTR), which leads to the production of a thick and viscous mucus layer that clogs the lungs of CF patients and traps pathogens, leading to chronic infections and inflammation and, ultimately, lung damage. In recent years, the use of peptides for the treatment of respiratory diseases, including CF, has gained growing interest. Therapeutic peptides for CF include antimicrobial peptides, inhibitors of proteases, and modulators of ion channels, among others. Peptides display unique features that make them appealing candidates for clinical translation, like specificity of action, high efficacy, and low toxicity. Nevertheless, the intrinsic properties of peptides, together with the need of delivering these compounds locally, e.g. by inhalation, raise a number of concerns in the development of peptide therapeutics for CF lung disease. In this review, we discuss the challenges related to the use of peptides for the treatment of CF lung disease through inhalation, which include retention within mucus, proteolysis, immunogenicity and aggregation. Strategies for overcoming major shortcomings of peptide therapeutics will be presented, together with recent developments in peptide design and optimization, including computational analysis and high-throughput screening.

Inhaled bosentan microparticles for the treatment of monocrotaline-induced pulmonary arterial hypertension in rats

The conventional treatment of pulmonary arterial hypertension (PAH) with oral bosentan hydrate has limitations related to the lack of pulmonary selectivity. In this study, we verified the hypothesis of the feasibility of dry powder inhalation of bosentan as an alternative to oral bosentan hydrate for the treatment of PAH. Inhalable bosentan microparticles with the capability of delivery to the peripheral region of the lungs and enhanced bioavailability have been formulated for PAH. The bosentan microparticles were prepared by the co-spray-drying method with bosentan hydrate and mannitol at different weight ratios. The bosentan microparticles were then characterized for their physicochemical properties, in vitro dissolution behavior, and in vitro aerodynamic performance. The in vivo pharmacokinetics and pathological characteristics were evaluated in a monocrotaline-induced rat model of PAH after intratracheal powder administration of bosentan microparticles, in comparison to orally administered bosentan hydrate. The highest performance bosentan microparticles, named SDBM 1:1, had irregular and porous shape. These microparticles had not only the significantly highest aerosol performance (MMAD of 1.91 μm and FPF of 51.68%) in the formulations, but also significantly increased dissolution rate, compared with the raw bosentan hydrate. This treatment to the lungs was also safe, as evidenced by the cytotoxicity assay. Intratracheally administered SDBM 1:1 elicited a significantly higher C_max and AUC_0-t that were over 10 times higher, compared with those of the raw bosentan hydrate administered orally in the same dose. It also exhibited ameliorative effects on monocrotaline-induced pulmonary arterial remodeling, and right ventricular hypertrophy. The survival rate of the group administrated SDBM1:1 intratracheally was 0.92 at the end of study (Positive control and orally administrated groups were 0.58 and 0.38, respectively). In conclusion, SDBM 1:1 showed promising in vitro and in vivo results with the dry powder inhalation. The inhaled bosentan microparticles can be considered as a potential alternative to oral bosentan hydrate for the treatment of PAH.

The Effect of Particle Size and Surface Roughness of Spray-Dried Bosentan Microparticles on Aerodynamic Performance for Dry Powder Inhalation

The purpose of this study was to prepare spray dried bosentan microparticles for dry powder inhaler and to characterize its physicochemical and aerodynamic properties. The microparticles were prepared from ethanol/water solutions containing bosentan using spray dryer. Three types of formulations (SD60, SD80, and SD100) depending on the various ethanol concentrations (60%, 80%, and 100%, respectively) were used. Bosentan microparticle formulations were characterized by scanning electron microscopy, powder X-ray diffraction, laser diffraction particle sizing, differential scanning calorimetry, Fourier-transform infrared spectroscopy, dissolution test, and in vitro aerodynamic performance using Andersen cascade impactor^™ (ACI) system. In addition, particle image velocimetry (PIV) system was used for directly confirming the actual movement of the aerosolized particles. Bosentan microparticles resulted in formulations with various shapes, surface morphology, and particle size distributions. SD100 was a smooth surface with spherical morphology, SD80 was a rough surfaced with spherical morphology and SD60 was a rough surfaced with corrugated morphology. SD100, SD80, and SD60 showed significantly high drug release up to 1 h compared with raw bosentan. The aerodynamic size of SD80 and SD60 was 1.27 µm and SD100 was 6.95 µm. The microparticles with smaller particle size and a rough surface aerosolized better (%FPF: 63.07 ± 2.39 and 68.27 ± 8.99 for SD60 and SD80, respectively) than larger particle size and smooth surface microparticle (%FPF: 22.64 ± 11.50 for SD100).

A Green RP-HPTLC-Densitometry Method for the Determination of Diosmin in Pharmaceutical Formulations

Green analytical technologies for the determination of a bioactive compound diosmin (DIOM) in the real samples of pharmaceutical formulations and biological fluids are scarce in literature. Therefore, the present investigation was carried out to develop a novel, rapid, simple, and economical green “reversed phase high-performance thin-layer chromatography (RP-HPTLC)” method for the determination of DIOM in commercial tablets and in-house developed spray-dried microparticles (MPs). The quantification of DIOM was conducted via “RP-18 silica gel 60 F254S HPTLC plates”. The binary combination of green solvents, i.e., ethanol:water (5.5:4.5 v/v) was proposed as a green mobile phase. The analysis of DIOM was conducted in absorbance/reflectance mode of densitometry at λmax = 348 nm. The densitograms of DIOM from the commercial tablets and in-house developed spray-dried MPs were verified by recording their single band at Rf = 0.80 ± 0.02 compared to standard DIOM. Green RP-HPTLC method was observed as linear in the range of 100–700 ng/band with R2 = 0.9995. The proposed method was found as “accurate, precise, robust, and sensitive” for the determination of DIOM in the real samples of commercial tablets and in-house developed spray-dried MPs. The % content of DIOM in the real samples of commercial tablets and in-house developed spray-dried MPs was obtained as 99.06 and 101.30%, respectively. The recorded results of this research suggested that the green RP-HPTLC method can be effectively used for the routine analysis of DIOM in pharmaceutical products.

Relationship between hydrate stability and accuracy of true density measured by helium pycnometry

Mechanical properties of a material, such as hardness and elastic modulus, depend on porosity exponentially. Thus, an accurate characterization of material mechanical properties requires correct porosity, which depends on the accuracy of measured true density. Helium pycnometry is the most common technique for determining true density of a powder material but it is not suitable for materials containing volatile components. For unstable hydrates, dehydration during measurement releases water and invalidates the ideal gas law used for calculating sample volume. Consequently, measured true density is over-estimated, which causes gross errors in mechanical properties extrapolated to zero porosity. This work shows that physical stability and the dehydration kinetics, determined by both water-bonding structures and bonding energy, directly affect the magnitude of error in measured true density.

Preparation and evaluation of tacrolimus-loaded thermosensitive solid lipid nanoparticles for improved dermal distribution

Background: Tacrolimus (TCR), also known as FK-506, is a biopharmaceutics classification system (BCS) class II drug that is insoluble in water because of its high log P values. After dermal application, TCR remains in the stratum corneum and passes through the skin layers with difficulty.

Purpose: The objectives of this study were to develop and evaluate solid lipid nanoparticles (SLNs) with thermosensitive properties to improve penetration and retention.

Methods: We prepared TCR-loaded thermosensitive solid lipid nanoparticles (TCR-SLNs) with different types of surfactants on the shell of the particle, which conferred the advantages of enhancing skin permeation and distribution. We also characterized them from a physic point of view and performed in vitro and in vivo evaluations.

Results: The TCR contained in the prepared TCR-SLN was in an amorphous state and entrapped in the particles with a high loading efficiency. The assessment of ex vivo skin penetration using excised rat dorsal skin showed that the TCR-SLNs penetrated to a deeper layer than the reference product (0.1% Protopic^®). In addition, the in vivo skin penetration test demonstrated that TCR-SLNs delivered more drug into deeper skin layers than the reference product. FT-IR images also confirmed drug distribution of TCR-SLNs into deeper layers of the skin.

Conclusion: These results revealed the potential application of thermosensitive SLNs for the delivery of difficult-to-permeate, poorly water-soluble drugs into deep skin layers.

Novel propyl karaya gum nanogels for bosentan: In vitro and in vivo drug delivery performance

The amphiphilic propyl Karaya gum (KG) with a degree of propyl group substitution of 3.24 was synthesized to design self-assembled nanogels as carriers for bosentan monohydrate, a poorly soluble antihypertensive drug. The drug was physically hosted into the hydrophobic core of the micellar nanogels by solvent evaporation method. TEM images revealed spherical shape and core-shell morphology of the nanogels. Depending upon polymer: drug weight ratio, the drug entrapment efficiency of >85% was attained. The carriers had hydrodynamic diameter in the range of 230-305 nm with narrow size distribution. The zeta potential of -23.0 to -24.9 mV and low critical association concentration (CAC) of 8.32 mg/l provided evidence that the colloidal nanogel system was physically stable. Thermodynamics of the propyl KG system in water favored spontaneous self-assembly of propyl KG. FTIR, thermal and x-ray analyses suggested that the drug was compatible in the hydrophobic confines of the nanogels. The micellar nanogels liberated their contents in simulated gastrointestinal condition in a pH-dependent manner over a period of 10 h. Peppas-Sahlin modeling of in vitro drug release data suggested that the polymer relaxation/swelling mechanism dominated the drug release process. Pre-clinical testing of the mucoadhesive nanogel formulations exhibited that the system could monitor the anti-hypertensive activity for a prolonged period. Overall, this propyl KG micellar nanogel system had a great potential and splendid outlook to serve as novel oral controlled release carriers for poorly soluble drugs with outstanding pharmacodynamics.

Overcoming multidrug resistance through inhalable siRNA nanoparticles-decorated porous microparticles based on supercritical fluid technology

BACKGROUND

In recent times, the co-delivery therapeutics have garnered enormous interest from researchers in the treatment of cancers with multidrug resistance (MDR) due to their efficient delivery of multiple agents, which result in synergistic effects and capable of overcoming all the obstacles of MDR in cancer. However, an efficient delivery platform is required for the conveyance of diverse agents that can successfully devastate MDR in cancer.

METHODS

Initially, short-interfering RNA-loaded chitosan (siRNA-CS) nanoparticles were synthesized using the ionic gelation method. Further, the siRNA-CS nanoparticles and doxorubicin hydrochloride (DOX) were co-loaded in poly-L-lactide porous microparticles (PLLA PMs) (nano-embedded porous microparticles, [NEPMs]) by the supercritical anti-solvent (SAS) process.

RESULTS AND DISCUSSION

The NEPM formulation exhibited an excellent aerodynamic performance and sustained release of DOX, which displayed higher anticancer efficacy in drug-resistant cells (human small cell lung cancer, H69AR cell line) than those treated with either free DOX and DOX-PLLA PMs due to the siRNA from CS nanoparticles silenced the MDR gene to DOX therapy.

CONCLUSION

This eco-friendly process provides a convenient way to fabricate such innovative NEPMs co-loaded with a chemotherapeutic agent and a gene, which can devastate MDR in cancer through the co-delivery system.

A review on recent technologies for the manufacture of pulmonary drugs

This review discusses recent developments in the manufacture of inhalable dry powder formulations. Pulmonary drugs have distinct advantages compared with other drug administration routes. However, requirements of drugs properties complicate the manufacture. Control over crystallization to make particles with the desired properties in a single step is often infeasible, which calls for micronization techniques. Although spray drying produces particles in the desired size range, a stable solid state may not be attainable. Supercritical fluids may be used as a solvent or antisolvent, which significantly reduces solvent waste. Future directions include application areas such as biopharmaceuticals for dry powder inhalers and new processing strategies to improve the control over particle formation such as continuous manufacturing with in-line process analytical technologies.