Chitosan-based binary dry powder inhaler carrier with nanometer roughness for improving in vitro and in vivo aerosolization performance

Surface Modification of lactose carrier particles using a fluid bed coater to improve fine particle fraction for dry powder inhalers

Surface roughness of carrier particles can impact dry powder inhaler (DPI) performance. There are opposing views on the effect of roughness on DPI performance. Hence, a systematic approach is needed to modify carrier surfaces and evaluate the impact on drug delivery. Carrier particle surfaces were modified by fluid bed coating with saturated lactose containing micronized lactose of different sizes (2, 5 and 8 μm) and coated to different levels (20, 40, 60 and 80%). Their drug delivery performance was assessed by the fine particle fraction (FPF). Roughness parameters, mean arithmetic roughness (R_a) and arithmetic mean height (S_a), of the carrier particles, were also evaluated using optical profilometry and scanning laser microscopy. Generally, particles of higher R_a had higher FPF. Higher S_a resulted in higher FPF only for particles with 60 and 80% coat levels. Reduced contact surface area between the drug particle and rougher carrier particle resulted in easier drug detachment during aerosolization. The 5 µm micronized lactose produced optimal carrier particles with respect to FPF and surface roughness. The study highlighted that with the ideal particles for surface roughening and coating level, surface roughening could be efficiently achieved by fluid bed coating for superior DPI performance.

Dry Powder Inhalers Based on Chitosan-Mannitol Binary Carriers: Effect of the Powder Properties on the Aerosolization Performance

Carriers play an important role in improving the aerosolization performance of dry powder inhalers (DPIs). Despite that intensive attention had been paid to the establishment of the advanced carriers with controllable physicochemical properties in recent years, the design and optimization of carrier-based DPIs remain an empiricism-based process. DPIs are a powder system of complex multiphase, and thus their physicochemical properties cannot fully explain the powder behavior. A comprehensive exposition of powder properties is demanded to build a bridge between the physicochemical properties of carriers and the aerosolization performance of DPIs. In this study, an FT-4 powder rheometer was employed to explore the powder properties, including dynamic flow energy, aeration, and permeability of the chitosan-mannitol binary carriers (CMBCs). CMBCs were self-designed as an advanced carrier with controllable surface roughness to obtain enhanced aerosolization performance. The specific mechanism of CMBCs to enhance the aerosolization performance of DPIs was elaborated based on the theory of pulmonary delivery processes by introducing powder properties. The results exhibited that CMBCs with appropriate surface roughness had lower special energy, lower aeration energy, and higher permeability. It could be predicted that CMBC-based DPIs had greater tendency to fluidize and disperse in airflow, and the lower adhesion force between particles enabled drugs to be detached from the carrier to achieve higher fine particle fractions. The specific mechanism on how physicochemical properties influenced the aerosolization performance during the pulmonary delivery processes could be figured out with the introduction of powder properties.

A real-time and modular approach for quick detection and mechanism exploration of DPIs with different carrier particle sizes

Dry powder inhalers (DPIs) had been widely used in lung diseases on account of direct pulmonary delivery, good drug stability and satisfactory patient compliance. However, an indistinct understanding of pulmonary delivery processes (PDPs) hindered the development of DPIs. Most current evaluation methods explored the PDPs with over-simplified models, leading to uncompleted investigations of the whole or partial PDPs. In the present research, an innovative modular process analysis platform (MPAP) was applied to investigate the detailed mechanisms of each PDP of DPIs with different carrier particle sizes (CPS). The MPAP was composed of a laser particle size analyzer, an inhaler device, an artificial throat and a pre-separator, to investigate the fluidization and dispersion, transportation, detachment and deposition process of DPIs. The release profiles of drug, drug aggregation and carrier were monitored in real-time. The influence of CPS on PDPs and corresponding mechanisms were explored. The powder properties of the carriers were investigated by the optical profiler and Freeman Technology four powder rheometer. The next generation impactor was employed to explore the aerosolization performance of DPIs. The novel MPAP was successfully applied in exploring the comprehensive mechanism of PDPs, which had enormous potential to be used to investigate and develop DPIs.

Mechanistic study of dissolution enhancement by interactive mixtures of chitosan with meloxicam as model

To enhance dissolution rate of meloxicam (MX), a poorly soluble model drug, a natural polysaccharide excipient chitosan (CH) is employed in this work as a carrier to prepare binary interactive mixtures by either mixing or co-milling techniques. The MX-CH mixtures of three different drug loads were characterized for morphological, granulometric, and thermal properties as well as drug crystallinity. The relative dissolution rate of MX was determined in phosphate buffer of pH 6.8 using the USP-4 apparatus; a significant increase in MX dissolution rate was observed for both mixed and co-milled mixtures comparing to the raw drug. Higher dissolution rate of MX was evidently connected to surface activation by mixing or milling, which was pronounced by the higher specific surface energy as detected by inverse gas chromatography. In addition to the particle size reduction, the carrier effect of the CH was confirmed for co-milling by linear regression between the MX maximum relative dissolution rate and the total surface area of the mixture (R² = 0.863). No MX amorphization or crystalline structure change were detected. The work of adhesion/cohesion ratio of 0.9 supports the existence of preferential adherence of MX to the coarse particles of CH to form stable interactive mixtures.

Engineering of levodopa inhalable microparticles in combination with leucine and dipalmitoylphosphatidylcholine by spray drying technique

The aim of this work was to study the effect of concomitant use of leucine and dipalmitoylphosphatidylcholine, in different ratios, on aerosolization performance of levodopa. Three-component formulations were selected based on a central composite design using percentages of leucine and dipalmitoylphosphatidylcholine as the independent variables. Particle size, surface roughness index, surface phosphorus and fine particle fraction were considered as dependent variables in the model. The spray dried samples were also characterized to determine their particle shape and solid state nature. levodopa was spray dried with 10-40% w/w of the excipients to prepare two- or three-component formulations. A crystalline nature was determined for levodopa in all samples spray dried from water:ethanol (30:70 v/v). Roughness in surface of the processed particles increased with increasing total concentration of the excipients, specially above 25% w/w. Analysis of phosphorus on the surface demonstrated that three-component formulations prepared with combination of 12.5% w/w leucine had the highest amount of dipalmitoylphosphatidylcholine in the surface, regardless of its percentage used in the initial feed. A combination of 12.43% w/w of leucine and 9.80% w/w of dipalmitoylphosphatidylcholine used in formulation exhibited the highest fine particle fraction (72.63%). It can be concluded that spray drying of levodopa with a suitable combination of both excipients leads to production of a three-component formulation of crystalline levodopa, with an aerosolization performance which is significantly higher than two-component formulations composed of the drug with either leucine or dipalmitoylphosphatidylcholine.

Development of Inhalable Nanostructured Lipid Carriers for Ciprofloxacin for Noncystic Fibrosis Bronchiectasis Treatment

PURPOSE

Ciprofloxacin (CIP) has poor lung targeting after oral inhalation. This study developed optimized inhalable nanostructured lipid carriers (NLCs) for CIP to enhance deposition and accumulation in deeper parts of the lungs for treatment of noncystic fibrosis bronchiectasis (NCFB).

METHODS

NLC formulations based on stearic acid and oleic acid were successfully prepared by hot homogenization and in vitro-characterized. CIP-NLCs were formulated into nanocomposite micro particles (NCMPs) for administration in dry powder inhalation (DPI) formulations by spray-drying (SD) using different ratios of chitosan (CH) as a carrier. DPI formulations were evaluated for drug content and in vitro deposition, and their mass median aerodynamic diameter (MMAD), fine particle fraction (FPF), fine particle dose (FPD), and emitted dose (ED) were determined.

RESULTS

The CIP-NLCs were in the nanometric size range (102.3 ± 4.6 nm), had a low polydispersity index (0.267 ± 0.12), and efficient CIP encapsulation (98.75% ± 0.048%), in addition to a spherical and smooth shape with superior antibacterial activity. The in vitro drug release profile of CIP from CIP-NLCs showed 80% release in 10 h. SD of CIP-NLCs with different ratios of CH generated NCMPs with good yield (>65%). The NCMPs had a corrugated surface, but with increasing lipid:CH ratios, more spherical, smooth, and homogenous NCMPs were obtained. In addition, there was a significant change in the FPF with increasing lipid:CH ratios (P ˂ 0.05). NCMP-1 (lipid:CH = 1:0.5) had the highest FPD (45.0 µg) and FPF (49.2%), while NCMP-3 (lipid:CH = 1:1.5) had the lowest FPF (37.4%). All NCMP powders had an MMAD in the optimum size range of 3.9-5.1 μm.

CONCLUSION

Novel inhalable CIP NCMP powders are a potential new approach to improved target ability and delivery of CIP for NCFB treatment.

Preparation of an oil suspension containing ondansetron hydrochloride as a sustained release parenteral formulation

Ondansetron hydrochloride (ODS) is a selective 5-hydroxytryptamine type 3 antagonist for nausea and emesis prevention in neoplastic patients. To reduce dosing frequency and side effects and improve patient compliance, a sustained release parenteral formulation of ODS was developed. Microparticles of methylcellulose (MC) and ODS were prepared using the spray-drying method and suspended in oils to form oil suspensions. The formulations were evaluated for residual moisture, drug content, size distribution, DSC, XRD, FTIR, SEM, drug release, and pharmacokinetic studies. The effects of polymers and oils on the drug release were evaluated. MC showed the most prominent sustained release effect among various polymers examined with the optimum MC/ODS ratio of 2:1 (w/w). The particle size of the produced microparticles was in the mean diameter of approximately 3 μm. Physicochemical characterization suggested that ODS existed in an amorphous matrix within the microparticles and interacted with MC via hydrogen bonds. Corn oil was selected as the appropriate oil for suspension due to the sustained release of ODS and the appropriate viscosity. The optimized sustained release formulation of ODS was the corn oil suspension of spray-dried microparticles containing MC and ODS (2:1, w/w). It showed an in vitro drug sustained release up to 120 h, while the oil suspension of ODS without any polymer released the drug within 2 h. Following subcutaneous administration in rats, the optimized formulation could prolong the drug release until 72 h with the enhanced bioavailability in comparison with the ODS solution. The oil suspension of spray-dried microparticles might be an efficient approach for prolongation of the drug effect in the management of nausea and emesis. Graphical abstract.