Feasibility of highly branched cyclic dextrin as an excipient matrix in dry powder inhalers

Building respirable powder architectures: utilizing polysaccharides for precise control of particle morphology for enhanced pulmonary drug delivery

INTRODUCTION

Dry powder inhaler (DPI) formulations are gaining attention as universal formulations with applications in a diverse range of drug formulations. The practical application of DPIs to pulmonary drugs requires enhancing their delivery efficiency to the target sites for various treatment modalities. Previous reviews have not explored the relation between particle morphology and delivery to different pulmonary regions. This review introduces new approaches to improve targeted DPI delivery using novel particle design such as supraparticles and metal-organic frameworks based on cyclodextrin.

AREAS COVERED

This review focuses on the design of DPI formulations using polysaccharides, promising excipients not yet approved by regulatory agencies. These excipients can be used to design various particle morphologies by controlling their physicochemical properties and manufacturing methods.

EXPERT OPINION

Challenges associated with DPI formulations include poor access to the lungs and low delivery efficiency to target sites in the lung. The restricted applicability of typical excipients contributes to their limited use. However, new formulations based on polysaccharides are expected to establish a technological foundation for the development of DPIs capable of delivering modalities specific to different lung target sites, thereby enhancing drug delivery.

Improvement in Inhalation Properties of Theophylline and Levofloxacin by Co-Amorphization and Enhancement in Its Stability by Addition of Amino Acid as a Third Component

Co-amorphous systems are amorphous formulations stabilized by the miscible dispersion of small molecules. This study aimed to design a stable co-amorphous system for the co-delivery of two drugs to the lungs as an inhaled formulation. Theophylline (THE) and levofloxacin (LEV) were used as model drugs for treating lung infection with inflammation. Leucine (LEU) or tryptophan (TRP) was employed as the third component to improve the inhalation properties. The co-amorphous system containing THE and LEV in an equal molar ratio was successfully prepared via spray drying where reduction of the particle size and change to the spherical morphology were observed. The addition of LEU or TRP at a one-tenth molar ratio to THE-LEV did not affect the formation of the co-amorphous system, but only TRP acted as an antiplasticizer. The Fourier transform infrared spectroscopy spectra revealed intermolecular interactions between THE and LEV in the co-amorphous system that were retained after the addition of LEU or TRP. The co-amorphous THE-LEV system exhibited better in vitro aerodynamic performance than a physical mixture of these compounds and permitted the simultaneous delivery of both drugs in various stages. The co-amorphous THE-LEV system crystallized at 40 °C, and this crystallization was not prevented by LEU. However, THE-LEV-TRP maintained its amorphous state for 1 month. Thus, TRP can act as a third component to improve the physical stability of the co-amorphous THE-LEV system, while maintaining the enhanced aerodynamic properties.

Porous particles and novel carrier particles with enhanced penetration for efficient pulmonary delivery of antitubercular drugs

This study aimed to design dry powder inhaler formulations using a hydrophilic polymeric polysaccharide, phytoglycogen (PyG), as a multi-functional additive that increases the phagocytic activity of macrophage-like cells and enhances pulmonary delivery of drugs. The safety and usefulness of PyG were determined using in vitro cell-based studies. Dry powder inhaler formulations of an antitubercular drug, rifampicin, were fabricated by spray drying with PyG. The cytotoxicity, effects on phagocytosis, particle size, and morphology were evaluated. The aerosolization properties of the powder formulations were evaluated using an Andersen cascade impactor (ACI). Scanning electron microscope images of the particles on each ACI stage were captured to observe the deposition behavior. PyG showed no toxicity in A549, Calu-3, or RAW264.7 cell lines. At concentrations of 0.5 and 1 g/L, PyG facilitated the cellular uptake of latex beads and the expression of pro-inflammatory cytokine genes in RAW264.7 cells. Formulations with outstanding inhalation potential were produced. The fine particle fraction (aerodynamic size 2-7 µm) of the porous particle batch reached nearly 60%, whereas in the formulation containing wrinkled carrier particles, the extra-fine particle fraction (aerodynamic particle size < 2 μm) was 25.0% ± 1.7%. The deposition of porous and wrinkled particles on individual ACI stages was distinct. The inclusion of PyG dramatically improved the inhalation performance of porous and wrinkled powder formulations. These easily inhaled immunostimulatory carrier particles may advance the state of research by enhancing the therapeutic effect and alveolar delivery of antitubercular drugs.

Characterization of spray-dried Gac aril extract and estimated shelf life of β-carotene and lycopene

Background

Fresh Gac (Momordica cochinchinensis) fruit is rich in carotenoids, mainly β-carotene and lycopene, but these compounds are sensitive to degradation. Spray drying is used to encapsulate the sensitive β-carotene and lycopene with different materials. Only a few reports of using highly branched cyclodextrin (HBCD) have been published. Additionally, studies of β-carotene and lycopene losses in Gac powders during storage are limited. Therefore, the encapsulation of β-carotene and lycopene of Gac aril with HBCD by spray drying at different inlet temperatures were compared. The shelf life of β-carotene and lycopene during storage was also calculated.

Methods

The fresh Gac aril was separated and kept frozen before the experiment. Gac aril and water (1:5 w/v) were centrifuged at 8,000 g at 20 °C for 15 min using a high-speed centrifuge (Sorval; Dupont, Wilmington, DE, USA). The supernatant was filtered twice and concentrated until 15° Brix using a rotary evaporator (R-200; Buchi, Flawil, Switzerland). The mixture of concentrated aril extract and highly branched cyclodextrin at 5% (w/v) was dried at three inlet temperatures by a spray dryer (B-290; Buchi, Flawil, Switzerland) with drying air flow rate, compressor air pressure, and feed rate set at 473 L/h, 40 m³/h, and 3 mL/min, respectively . The physicochemical qualities, particle image morphology, and estimated storage time of β-carotene and lycopene were determined.

Results

Increased inlet temperatures of spray drying decreased the bulk density, β-carotene, and lycopene content of spray-dried powders significantly. The color values of dried powders had significant differences in yellowness (b*) and chroma, but not lightness (L*), redness (a*), and hue when the inlet temperature increased from 160 °C to 180 °C. The maximum reduction of β-carotene and lycopene observed during storage at 55 °C was 90.88% and 91.11% for 33 and 18 days. For β-carotene, the estimated shelf-life (retention of 50% of β-carotene) was 9.9, 48.4, and 91.6 days at 25 °C, 10 °C, and 4 °C. The shelf-life of lycopene was 26, 176, and 357 days at 25 °C, 10 °C, and 4 °C, respectively. HBCD could be potentially used as an encapsulating agent in spray-dried Gac aril, but the shelf-life of β-carotene and lycopene needs to be improved to be useful as a food ingredient.

The 4R's Framework of Nutritional Strategies for Post-Exercise Recovery: A Review with Emphasis on New Generation of Carbohydrates

Post-exercise recovery is a broad term that refers to the restoration of training capacity. After training or competition, there is fatigue accumulation and a reduction in sports performance. In the hours and days following training, the body recovers and performance is expected to return to normal or improve. ScienceDirect, PubMed/MEDLINE, and Google Scholar databases were reviewed to identify studies and position declarations examining the relationship between nutrition and sports recovery. As an evidence-based framework, a 4R’s approach to optimizing post-exercise recovery was identified: (i) Rehydration—a fundamental process that will depend on the athlete, environment and sports event; (ii) Refuel—the consumption of carbohydrates is not only important to replenish the glycogen reserves but also to contribute to the energy requirements for the immune system and tissue reparation. Several bioengineered carbohydrates were discussed but further research is needed; (iii) Repair—post-exercise ingestion of high-quality protein and creatine monohydrate benefit the tissue growth and repair; and (iv) Rest—pre-sleep nutrition has a restorative effect that facilitates the recovery of the musculoskeletal, endocrine, immune, and nervous systems. Nutritional consultancy based on the 4R’s is important for the wise stewardship of the hydration, feeding, and supplementation strategies to achieve a timely recovery.

Water-assisted synthesis of mesoporous calcium carbonate with a controlled specific surface area and its potential to ferulic acid release

A carbonation process to control the specific surface area of mesoporous calcium carbonate and the dissolution profile of ferulic acid on mesoporous carbonate particles are presented. The effects of water content on the physicochemical properties, specific surface area, pore size, crystallinity, and morphology are evaluated. Mesoporous calcium carbonate particles are synthesised with well-controlled specific surface areas of 38.8 to 234 m² g⁻¹. Each of the submicron-size secondary particles consists of a primary particle of nano-size. During secondary particle formation, primary particle growth is curbed in the case with less water content. By contrast, growth is promoted via dissolution and recrystallisation in the presence of water. The release rates of ferulic acid are gradually enhanced with increasing specific surface area of the mesoporous calcium carbonate, that reflects crystallinity of ferulic acid.

A carbonation process to control the specific surface area of mesoporous calcium carbonate and the dissolution profile of ferulic acid on mesoporous carbonate particles are presented.

Synthesis of novel α-glucans with potential health benefits through controlled glucose release in the human gastrointestinal tract

The glycemic carbohydrates we consume are currently viewed in an unfavorable light in both the consumer and medical research worlds. In significant part, these carbohydrates, mainly starch and sucrose, are looked upon negatively due to their rapid and abrupt glucose delivery to the body which causes a high glycemic response. However, dietary carbohydrates which are digested and release glucose in a slow manner are recognized as providing health benefits. Slow digestion of glycemic carbohydrates can be caused by several factors, including food matrix effect which impedes α-amylase access to substrate, or partial inhibition by plant secondary metabolites such as phenolic compounds. Differences in digestion rate of these carbohydrates may also be due to their specific structures (e.g. variations in degree of branching and/or glycosidic linkages present). In recent years, much has been learned about the synthesis and digestion kinetics of novel α-glucans (i.e. small oligosaccharides or larger polysaccharides based on glucose units linked in different positions by α-bonds). It is the synthesis and digestion of such structures that is the subject of this review.

Imagine the Superiority of Dry Powder Inhalers from Carrier Engineering

Inhalation therapy has strong history of more than 4000 years and it is well recognized around the globe within every culture. In early days, inhalation therapy was designed for treatment of local disorders such as asthma and other pulmonary diseases. Almost all inhalation products composed a simple formulation of a carrier, usually α-lactose monohydrate orderly mixed with micronized therapeutic agent. Most of these formulations lacked satisfactory pulmonary deposition and dispersion. Thus, various alternative carrier's molecules and powder processing techniques are increasingly investigated to achieve suitable aerodynamic performance. In view of this fact, more suitable and economic alternative carrier's molecules with advanced formulation strategies are discussed in the present review. Furthermore, major advances, challenges, and the future perspective are discussed.