Self-Delivery Janus-Prodrug for Precise Immuno-Chemotherapy of Colitis-Associated Colorectal Cancer

Aromatized thioketal (ATK) linked the immunoregulatory molecule (budesonide, Bud) and the cytotoxic molecule (gemcitabine, Gem) to construct a ROS-activated Janus-prodrug, termed as BAG. Benefiting from the hydrogen bonding, π-π stacking, and other intermolecular interactions, BAG could self-assemble into nanoaggregates (BAG NA) with a well-defined spherical shape and uniform size distribution. Compared to the carrier-based drug delivery system, BAG NA have ultrahigh drug loading content and ROS concentration-dependent drug release. Colitis-associated colorectal cancer (CAC) is a typical disease in which chronic inflammation transforms into tumors. BAG NA can be internalized by colon cancer C26 cells and then triggered by excessive intracellular ROS to release nearly 100% of the drugs. Based on this, BAG NA showed a stronger pro-apoptotic effect than free Bud combined with free Gem. What is gratifying is that orally administered BAG NA can precisely accumulate in the diseased colon tissues of CAC mice induced by AOM/DSS and simultaneously release Bud and Gem. Bud can regulate the tumor immune microenvironment to restore and enhance the cytotoxicity of Gem. Therefore, BAG NA maximizes the synergistic therapeutic effect through co-delivery of Bud and Gem. This work provided a cutting-edge method for constructing self-delivery Janus-prodrug based on ATK and confirmed its potential application in inflammation-related carcinogenesis.

Ternary nanocomposite carriers based on organic clay-lipid vesicles as an effective colon-targeted drug delivery system: preparation and in vitro/in vivo characterization

This study aimed to develop a new colon-targeted drug delivery system via the preparation of ternary nanocomposite carriers based on organic polymer, aminoclay and lipid vesicles. Budesonide (Bud), an anti-inflammatory drug was chosen as a model drug and encapsulated into three different formulations: liposome (Bud-Lip), aminoclay-coated liposome (AC-Bud-Lip), and Eudragit® S100-aminoclay double coated liposome (EAC-Bud-Lip). The formation of the aminoclay-lipid vesicle nanocomposite was confirmed by energy dispersive X-ray spectrum, transmission electron microscopy, and Fourier-transform infrared spectroscopy. All formulations were produced with a high encapsulation efficiency in a narrow size distribution. Drug release from EAC-Bud-Lip was approximately 10% for 2-h incubation at pH 1.2, implying the minimal drug release in acidic gastric condition. At pH 7.4, EAC-Bud-Lip underwent significant size reduction and exhibited drug release profiles similar to that from AC-Bud-Lip, implying the pH-dependent removal of the outer coating layer. Compared to free Bud solution, EAC-Bud-Lip achieved a higher drug uptake in Caco-2 cells and exhibited a stronger inhibition of TNF-α and IL-6 secretion in LPS-stimulated Raw264.7 cells. Furthermore, a bio-distribution study in mice demonstrated that Eudragit® S100-aminoclay dual coating led to a higher colonic distribution with a longer residence time, which correlated well with the delayed systemic drug exposure in rats. Taken together, the present study suggests that the ternary nanocomposite carrier consisting of Eudragit® S100, aminoclay, and lipid vesicle might be useful as an effective colon-targeted drug delivery system.

Efficacy of budesonide-loaded mesoporous silica microparticles capped with a bulky azo derivative in rats with TNBS-induced colitis

A colon targeted drug delivery system for inflammatory bowel diseases (IBD), consisting in budesonide loaded mesoporous silica microparticles functionalized with a selective azo-molecular gate (M-Bud), has been evaluated for in vivo efficacy. Experimental colitis in male Wistar rats was induced by rectal instillation of 2,4,6-trinitrobenzenesulfonic acid (TNBS). M-Bud was orally administered to the rats as a suspension in water. Colon/body weight ratio, clinical activity score, and histological evaluation were used as inflammatory indices to measure the performance of the microparticles. The formulation was compared with a suspension prepared from the commercial drug Entocord®. Statistical analyses of all scores indicate that the controlled release of budesonide in colon from M-Bud showed efficacy similar to that of Entocord in the healing of induced colitis in rats.

Characterization of a dextran-budesonide prodrug for inhalation therapy

Reducing the dosing frequency of corticosteroids may increase compliance and increase pulmonary targeting. The objective of this study was to evaluate whether a high molecular weight dextran-budesonide conjugate might be suitable for pulmonary slow release of the otherwise fast absorbed budesonide. An array of dextran-spacer-budesonide conjugates was prepared that differed in the molecular weight of dextran (20 kDa or 40 kDa) and the length of the dicarboxylic spacer (succinic, glutaric, and adipic anhydride). The conjugates were characterized for identity by proton nuclear magnetic resonance (¹H NMR) and Fourier-transform infrared spectroscopy (FTIR), the degree of dextran-hydroxyl conjugation, purity, and physiological activation (release of budesonide). The 40 kDa dextran-succinate-budesonide conjugate was formulated as a dry powder for pulmonary delivery and characterized for particle size distribution, particle morphology, and aerodynamic particle size. The degree of substitution (grams of budesonide in 100 g of conjugate) ranged from 4 to 10% for all six dextran-spacer-budesonide conjugates. Incubation at 37 °C and pH 7.4 in phosphate buffered saline resulted in release of 25-75% of the conjugated budesonide over an 8-hour period with the rate of release increasing with molecular weight of dextran and the length of the spacer. Modeling of the concentration time profiles of the released budesonide and budesonide-21-hemisucinate in phosphate buffered saline, suggested that budesonide is generated either directly or via the budesonide-21-hemisucinate pre-cursor. Data also suggested that the rate of budesonide generation likely depends on the position of budesonide on the dextran molecule. Spray-drying the 40 kDa dextran-succinate-budesonide produced respirable particles of the conjugate with a mass median aerodynamic particle size (MMAD) of 4 μm. The slow generation of budesonide from the chemical delivery system might further improve the pharmacological profile of budesonide.

Polymer-Lipid Microparticles for Pulmonary Delivery

Toward engineering approaches that are designed to optimize the particle size, morphology, and mucoadhesion behavior of the particulate component of inhaler formulations, this paper presents the preparation, physicochemical characterization, and preliminary in vitro evaluation of multicomponent polymer-lipid systems that are based on "spray-drying engineered" α-lactose monohydrate microparticles. The formulations combine an active (budesonide) with a lung surfactant (dipalmitoylphosphatidylcholine) and with materials that are known for their desirable effects on morphology (polyvinyl alcohol), aerosolization (l-leucine), and mucoadhesion (chitosan). The effect of the composition of formulations on the morphology, distribution, and in vitro mucoadhesion profiles is presented along with "Calu-3 cell monolayers" data that indicate good cytocompatibility and also with simulated-lung-fluid data that are consistent with the therapeutically useful release of budesonide.

pH-triggered surface charge-reversal nanoparticles alleviate experimental murine colitis via selective accumulation in inflamed colon regions

In this study, we developed pH-triggered surface charge-reversal lipid nanoparticles (LNPs), loaded with budesonide, which could precisely deliver the drug to inflamed colon segments for the treatment of ulcerative colitis. Polyethyleneimine (PEI) was used to render LNPs cationic (PEI-LNPs), and Eudragit® S100 (ES) was coated on PEI-LNPs to obtain pH-triggered charge-reversal LNPs (ES-PEI-LNPs). ES coating avoided a burst drug release under acidic conditions mimicking the stomach and early small intestine environments and showed a sustained release in the colon. The surface charge of ES-PEI-LNPs switched from negative to positive under colonic conditions owing to pH-triggered removal of the ES coating. Bioimaging of the mouse gastrointestinal tract and confocal analysis of colon tissues revealed that ES-PEI-LNPs selectively accumulated in an inflamed colon. Furthermore, ES-PEI-LNPs mitigated experimental colitis in mice. These results suggest that the pH-triggered charge-reversal LNPs could be a promising drug carrier for ulcerative colitis therapy and other colon-targeted treatments.

Atomic scale surface engineering of micro- to nano-sized pharmaceutical particles for drug delivery applications

Atomic layer deposition on pharmaceutical particles for drug delivery applications is demonstrated using assisted fluidized bed dry powder processing. Complete and conformal layering is achieved on particle sizes from the lower micron to upper nanometer range under near ambient conditions. As few as 2-14 atomic alumina layers alter particle properties: dissolution, dispersibility and heat transfer.

Physical and Chemical Stability of Budesonide Mucoadhesive Oral Suspensions (MucoLox)

Budesonide is a corticosteroid that has been shown effective in the treatment of eosinophilic esophagitis, but there are currently no commercial medicines to treat this chronic allergic/immune condition, despite its prevalence in the U.S. Therefore, pharmaceutical compounding is the alternative choice to meet the therapeutic need of eosinophilic esophagitis patients. Two budesonide mucoadhesive oral suspensions (1 mg/10 mL and 2 mg/10 mL) were developed using the compounding vehicle MucoLox, a proprietary mucoadhesive polymer blend that promotes mucosal adhesion. The physical and chemical stability of the oral suspensions was tested over a period of 182 days, at room temperature and refrigerated conditions, in order to determine the corresponding beyond-use date. The physical characterization consisted in observing all samples for color/appearance and odor, and testing for pH and density, whereas the chemical characterization consisted in ultra-performance liquid chromatography assay testing. Both oral suspensions were proven physically and chemically stable, and the ultra-performance liquid chromatography method was proven stability indicating. As a result, the beyond-use date of the budesonide 1-mg/10-mL and 2-mg/10-mL mucoadhesive oral suspensions (MucoLox), in amber plastic bottles, is six months at both room temperature and refrigerated conditions.

Validating Whole-Airway CFD Predictions of DPI Aerosol Deposition at Multiple Flow Rates

BACKGROUND

The objective of this study was to compare aerosol deposition predictions of a new whole-airway CFD model with available in vivo data for a dry powder inhaler (DPI) considered across multiple inhalation waveforms, which affect both the particle size distribution (PSD) and particle deposition.

METHODS

The Novolizer DPI with a budesonide formulation was selected based on the availability of 2D gamma scintigraphy data in humans for three different well-defined inhalation waveforms. Initial in vitro cascade impaction experiments were conducted at multiple constant (square-wave) particle sizing flow rates to characterize PSDs. The whole-airway CFD modeling approach implemented the experimentally determined PSDs at the point of aerosol formation in the inhaler. Complete characteristic airway geometries for an adult were evaluated through the lobar bronchi, followed by stochastic individual pathway (SIP) approximations through the tracheobronchial region and new acinar moving wall models of the alveolar region.

RESULTS

It was determined that the PSD used for each inhalation waveform should be based on a constant particle sizing flow rate equal to the average of the inhalation waveform's peak inspiratory flow rate (PIFR) and mean flow rate [i.e., AVG(PIFR, Mean)]. Using this technique, agreement with the in vivo data was acceptable with <15% relative differences averaged across the three regions considered for all inhalation waveforms. Defining a peripheral to central deposition ratio (P/C) based on alveolar and tracheobronchial compartments, respectively, large flow-rate-dependent differences were observed, which were not evident in the original 2D in vivo data.

CONCLUSIONS

The agreement between the CFD predictions and in vivo data was dependent on accurate initial estimates of the PSD, emphasizing the need for a combination in vitro-in silico approach. Furthermore, use of the AVG(PIFR, Mean) value was identified as a potentially useful method for characterizing a DPI aerosol at a constant flow rate.

Nanoencapsulated budesonide in self-stratified polyurethane-polyurea nanoparticles is highly effective in inducing human tolerogenic dendritic cells

The design of innovative strategies to selectively target cells, such antigen-presenting cells and dendritic cells, in vivo to induce immune tolerance is gaining interest and relevance for the treatment of immune-mediated diseases. A novel loaded-nanosystem strategy to generate tolerogenic dendritic cells (tol-DCs) was evaluated. Hence budesonide (BDS) was encapsulated in multiwalled polyurethane-polyurea nanoparticles (PUUa NPs-BDS) based on self-stratified polymers by hydrophobic interactions at the oil-water interface. DCs treated with encapsulated BDS presented a prominent downregulation of costimulatory molecules (CD80, CD83 and MHCII) and upregulation of inhibitory receptors. Moreover, DCs treated with these PUUa NPs-BDS also secreted large amounts of IL-10, a crucial anti-inflammatory cytokine to induce tolerance, and inhibited T lymphocyte activation in a specific manner compared to those cells generated with free BDS. These results demonstrate that PUUa NPs-BDS are a highly specific and efficient system through which to induce DCs with a tolerogenic profile. Given the capacity of PUUa NPs-BDS, this delivery system has a clear advantage for translation to in vivo studies.

Co-spray dried resveratrol and budesonide inhalation formulation for reducing inflammation and oxidative stress in rat alveolar macrophages

Oxidative stress is instrumental in the pathogenesis and progression of chronic obstructive pulmonary disease (COPD). Novel therapeutic strategies that target macrophages, based on the use of antioxidant compounds, could be explored to improve corticosteroid responses in COPD patients. In this study, inhalable microparticles containing budesonide (BD) and resveratrol (RES) were prepared and characterized. This approach was undertaken to develop a multi-drug inhalable formulation with anti-oxidant and anti-inflammatory activities for treatment of chronic lung diseases. The inhalable microparticles containing different ratios of BD and RES were prepared by spray drying. The physico-chemical properties of the formulations were characterized in terms of surface morphology, particle size, physical and thermal stability. Additionally, in vitro aerosol performances of these formulations were evaluated with the multi-stage liquid impinger (MSLI) at 60 and 90 l/min, respectively. The cytotoxicity effect of the formulations was evaluated using rat alveolar macrophages. The biological responses of alveolar macrophages in terms of cytokine expressions, nitric oxide (NO) production and free radical scavenging activities were also tested. The co-spray dried (Co-SD) microparticles of all formulations exhibited morphologies appropriate for inhalation administration. Analysis of the deposition profiles showed an increase in aerosol performance proportional to BD concentration. Cell viability assay demonstrated that alveolar macrophages could tolerate a wide range of RES and BD concentrations. In addition, RES and BD were able to decrease the levels of tumour necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) in lipopolysaccharide (LPS) induced alveolar macrophages. This study has successfully established the manufacture of Co-SD formulations of RES and BD with morphology and aerosol properties suitable for inhalation drug delivery, negligible in vitro toxicity and enhanced efficacy to control inflammation and oxidative stress in LPS-induced alveolar macrophages.

[Preparation of budesonide sustained-release dry powder for inhalation and influence of lactose content]

Using high pressure homogenization method combined with spray-drying, budesonide-loaded chitosan microparticles were prepared and the in vitro release profile was investigated. The microparticles were then blended with lactose using a vortex mixer, influence of mixing speed, mixing time on drug recovery rate and content homogeneity were investigated. Meanwhile, influence of lactose content on drug recovery rate, content homogeneity, powder flowability and in vitro deposition were studied. It turned out that budesonide was released from the microparicles in a sustained manner, with fine particle fraction as high as 46.0%, but the powder flowability was poor. After blending with 10 times of lactose, the drug recovery rate was 96.5%, with relative standard deviation of drug content 2.5%, and fine particle fraction of the formulation increased to 59.6% with good flowability. It's demonstrated that using a vortex mixer, budesonide sustained-release dry powder for inhalation with good recovery and content homogeneity could be prepared, the formulation had good flowability and was suitable for pulmonary inhaling.

Budesonide-loaded guar gum microspheres for colon delivery: preparation, characterization and in vitro/in vivo evaluation

A novel budesonide (BUD) colon delivery release system was developed by using a natural polysaccharide, guar gum. The rigidity of the microspheres was induced by a chemical cross-linking method utilizing glutaraldehyde as the cross-linker. The mean particle size of the microspheres prepared was found to be 15.21 ± 1.32 µm. The drug loading and entrapment efficiency of the formulation were 17.78% ± 2.31% and 81.6% ± 5.42%, respectively. The microspheres were spherical in shape with a smooth surface, and the size was uniform. The in vitro release profiles indicated that the release of BUD from the microspheres exhibited a sustained release behavior. The model that fitted best for BUD released from the microspheres was the Higuchi kinetic model with a correlation coefficient r = 0.9993. A similar phenomenon was also observed in a pharmacokinetic study. The prolongation of the half-life (t_1/2), enhanced residence time (mean residence time, MRT) and decreased total clearance (CL) indicated that BUD microspheres could prolong the acting time of BUD in vivo. In addition, BUD guar gum microspheres are thought to have the potential to maintain BUD concentration within target ranges for a long time, decreasing the side effects caused by concentration fluctuation, ensuring the efficiency of treatment and improving patient compliance by reducing dosing frequency. None of the severe signs, like the appearance of epithelial necrosis and the sloughing of epithelial cells, were detected.

Silicone surface with drug nanodepots for medical devices

An ideal surface of poly(dimethylsiloxane) (PDMS) medical devices requires sustained drug release to combat various tissue responses and infection. At present, a noncovalent surface coating with drug molecules using binders possesses a detachment problem, while covalently linking drug molecules to the surface provides no releasable drug. Here, a platform that allows the deposition of diverse drugs onto the PDMS surface in an adequate quantity with reliable attachment and a sustained-release character is demonstrated. First, a PDMS surface with carboxyl functionality (PDMS-COOH) is generated by subjecting a PDMS piece to an oxygen plasma treatment to obtain silanol moieties on its surface, then condensing the silanols with (3-aminopropyl)triethoxysilane molecules to generate amino groups, and finally reacting the amino groups with succinic anhydride. The drug-loaded carriers with hydroxyl groups on their surface can then be esterified to PDMS-COOH, resulting in a PDMS surface covalently grafted with drug-filled nanocarriers so that the drugs inside the securely grafted carriers can be released. Demonstrated here is the covalent linking of the surface of a PDMS endotracheal tube with budesonide-loaded ethylcellulose nanoparticles. A secure and high drug accumulation at the surface of the tubes (0.025 mg/cm2) can be achieved without changes in its bulk property such as hardness (Shore-A), and sustained release of budesonide with a high release flux during the first week followed by a reduced release flux over the subsequent 3 weeks can be obtained. In addition, the grafted tube possesses more hydrophilic surface and thus is more tissue-compatible. The grafted PDMS pieces show a reduced in vitro inflammation in cell culture and a lower level of in vivo tissue responses, including a reduced level of inflammation, compared to the unmodified PDMS pieces, when implanted in rats. Although demonstrated with budesonide and a PDMS endotracheal tube, this platform of grafting a PDMS surface with drug-loaded particles can be applied to other drugs and other devices.

Physicochemical compatibility of nebulizable drug admixtures containing budesonide and colistimethate or hypertonic saline

Knowledge of the physicochemical compatibility of admixtures of nebulizable drugs is an important issue. In this article, the results of our recent study dealing with the compatibility of drug admixtures containing budesonide and colistin methanesulfonate (brand name Colistin CF) or budesonide and 5.85% sodium chloride solution are presented, as well as the up-to-date version of our compatibility table. Admixtures were prepared by mixing 2.0 mL Pulmicort either with 3.0 mL Colistin CF or 4.0 mL 5.85% sodium chloride solution. Test solutions were stored for 24 hours at room temperature under ambient light conditions. Physical compatibility was determined by measuring pH and osmolality. Concentrations of budesonide were measured by a high-performance liquid chromatography assay. The antibiotic activity of colistin methanesulfonate was determined in comparison to standard solutions using a microbiological assay. No loss in drug concentration of budesonide and no change in antibiotic activity of colistin methanesulfonate were detected over a test period of 24 hours. Osmolality remained unchanged in both types of admixtures. In admixtures of budesonide with colistin methanesulfonate, pH increased during the first 4 hours of storage, while in admixtures of budesonide and hypertonic saline pH remained unchanged. No visible changes could be detected. Due to these results admixtures of budesonide and colistin methanesulfonate or 5.85% sodium chloride solution are designated to be compatible, but it is recommended that mixing should take place immediately before administration. Further investigations are needed to determine whether or not drug delivery is affected by mixing the drugs and to ensure simultaneous nebulization is recommendable.

Aerosol characteristics of admixture of budesonide inhalation suspension with a beta2-agonist, procaterol

BACKGROUND

Nebulized drugs for asthma treatment are often mixed together in order to simplify inhalation regimens, although not recommended. We therefore evaluated aerosol characteristics and physicochemical stability of the admixture of an inhaled corticosteroid suspension with a beta2-agonist solution.

METHODS

An 8-stage cascade impactor was used to measure the particle size distribution of admixture of Pulmicort® Respules® (budesonide, 0.5mg/2mL) with Meptin® Inhalation Solution Unit (procaterol hydrochloride, 30μg/0.3mL) from a jet nebulizer, PARI LC Plus®. Concentration of each drug was assayed with high-pressure liquid chromatography. Physicochemical compatibility was also assessed up to 24 hours after mixing.

RESULTS

With regard to budesonide, impactor parameters such as mass median aerodynamic diameter (MMAD) and respirable mass (RM) were comparable between admixtures and single-drug preparations (2.92 ± 0.03 vs 2.99 ± 0.14μm, 146.8 ± 2.9 vs 147.6 ± 8.2μg, respectively). On the other hand, delivery rates of procaterol increased when admixed with budesonide suspension, resulting in significantly higher RM (15.1 ± 0.8 vs 10.2 ± 0.5μg, p < 0.01). Variations from initial concentration in the percentages of drug remaining at any time point were less than 10%, and there were no appreciable changes in pH of the admixtures for up to 24 hours.

CONCLUSIONS

There is a possibility that admixture might influence of aerodynamic characteristics of procaterol, but not budesonide. In vivo data will be needed for the clinical implications of our findings.

Simultaneous quantification of 22R and 22S epimers of budesonide in human plasma by ultra-high-performance liquid chromatography-tandem mass spectrometry: application in a stereoselective pharmacokinetic study

Budesonide (BUD) is used as a mixture of 22R and 22S epimers for the topical treatment of asthma, rhinitis, and inflammatory bowel disease. To study stereoselectivity in the pharmacokinetics of each epimer, we developed a stereoselective and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry method for the quantitative determination of 22R and 22S epimers of BUD in human plasma. The epimers of BUD were extracted from plasma using n-hexane/dichloromethane/isopropanol (2:1:0.1, v/v/v) under alkaline conditions. Baseline separation was obtained within 7min on an Acquity UPLC BEH C18 (50mm×2.1mm, 1.7μm) column using an isocratic mobile phase consisting of acetonitrile/5mM ammonium acetate/acetic acid (29:71:0.142, v/v/v) at a flow rate of 0.7mL/min. Mass spectrometric detection was performed in a multiple reaction monitoring mode using the m/z 489→357 transition for BUD epimers and the m/z 497→357 transition for the internal standard d8-BUD epimers. Calibration curves were linear over the concentration ranges of 5.0-500 and 5.0-3000pg/mL for 22R-BUD and 22S-BUD, respectively. The lower limit of quantification was 5.0pg/mL for both epimers. The method was successfully applied in a pharmacokinetic study of BUD controlled-release capsules in humans. Consistent differences in the pharmacokinetics of the 22R and 22S epimers were observed, the AUC(0-∞) of 22S-BUD was approximately six times higher than that of 22R-BUD, and the 22S-/22R-BUD ratio of total body clearance was 0.17.

Preparation, in vitro and in vivo evaluation of budesonide loaded core/shell nanofibers as oral colonic drug delivery system

Budesonide (BUD) loaded ethylcellulose (EC)-core/Eudragit S100-shell nanofibers (BUD-core/shell-NFs) have been successfully prepared using a coaxial electrospinning technique. The drug encapsulation efficiency was 90.48%. SEM and TEM analysis showed that fine core-shell structured nanofibers with an average diameter 190 nm and uniform core diameters 74 nm were prepared. The BUD-loaded Eudragit S100/EC composite nanofibers (BUD-NFs) were prepared using a blend electrospinning method and used as a control. In vitro release tests in HCl 0.1 N, phosphate buffer solutions pH 6.8 and 7.4 were studied. Moreover, the colon-specific characteristics were directly proven in vivo by the content of BUD in different segments of the gastrointestinal (GI) tract in rats after oral administration. Taken together, the results confirmed that BUD-core/shell-NFs had desired pH-dependent drug release profile, displayed a sustained and complete drug release in the colon, as well as protected BUD from being released completely in the upper portion of the GI tract. Compared with BUD-NFs, the BUD-core/shell-NFs have much better potential to be developed as oral colon-specific drug delivery system (OCDDS) to overcome the disadvantages of current oral formulations of BUD.

Investigation and comparison of colon specificity of novel polymer khaya gum with guar gum

To investigate the colon specificity of novel natural polymer khaya gum and compare with guar gum. Release profile of tablets was carried out in presence and absence of rat cecal contents. The fast disintegrating core tablets of budesonide, were initially prepared by direct compression technique. Later, these tablets were coated with khaya gum or guar gum. After suitable pre compression and post compression evaluation, these tablets were further coated using Eudragit L-100 by dip coating technique. X-ray images were taken to investigate the movement, location and the integrity of the tablets in different parts of gastro intestinal tract in rabbits. The release profiles revealed that khaya gum or guar gum, when used as compression coating, protected the drug from being released in the upper parts of the gastro intestinal tract to some extent but the enteric coated formulations completely protected the drug from being released in the upper parts of the gastro intestinal tract, and released the drug in the colon by bacterial degradation of gums. It was found that both the polysaccharide polymers exhibited different release profiles in presence and absence of rat cecal contents. However, further enteric coat helped in targeting the drug to colon very effectively. Better dissolution models revealed the colon specificity of polysaccharides and alone can not be used either for targeting the drug to the colon or for sustaining or controlling the release of drug.

Intratracheal budesonide-poly (lactide-co-glycolide) microparticles reduce oxidative stress, VEGF expression, and vascular leakage in a benzo(a)pyrene-fed mouse model

The purpose of this study was to determine whether intratracheally instilled polymeric budesonide microparticles could sustain lung budesonide levels for one week and inhibit early biochemical changes associated with benzo(a)pyrene (B[a]P) feeding in a mouse model for lung tumours. Polymeric microparticles of budesonide-poly (dl-lactide-co-glycolide) (PLGA 50:50) were prepared using a solvent evaporation technique and characterized for their size, morphology, encapsulation efficiency, and in-vitro release. The microparticles were administered intratracheally (i.t.) to B[a]P-fed A/J mice. At the end of one week drug levels in the lung tissue and bronchoalveolar lavage (BAL) were estimated using HPLC and compared with systemic (intramuscular) administration. In addition, in-vivo end points including malondialdehyde (MDA), glutathione (GSH), total protein levels and vascular endothelial growth factor (VEGF) in BAL, and VEGF and c-myc mRNA levels in the lung tissue were assessed at the end of one week following intratracheal administration of budesonide microparticles. Budesonide-PLGA microparticles (1–2 μm), with a budesonide loading efficiency of 69–94%, sustained in-vitro budesonide release for over 21 days. Compared with the intramuscular route, intratracheally administered budesonide-PLGA microparticles resulted in higher budesonide levels in the BAL and lung tissue. In-vivo, B[a]P-feeding increased BAL MDA, lung VEGF mRNA, lung c-myc mRNA, BAL total protein, and BAL VEGF levels by 60, 112, 71, 154, and 78%, respectively, and decreased BAL GSH by 62%. Interestingly, intratracheally administered budesonide-PLGA particles inhibited these biochemical changes. Thus, biodegradable budesonide microparticles sustained budesonide release and reduced MDA accumulation, GSH depletion, vascular leakage, and VEGF and c-myc expression in B[a]P-fed mice, indicating the potential of locally delivered sustained-release particles for inhibiting angiogenic factors in lung cancer.

Chemical and physical compatibility of levalbuterol inhalation solution concentrate mixed with budesonide, ipratropium bromide, cromolyn sodium, or acetylcysteine sodium

BACKGROUND

Medications are frequently combined in the nebulizer cup, so it is important to determine their chemical and physical compatibility.

OBJECTIVE

To determine the chemical and physical compatibility of levalbuterol with ipratropium bromide, cromolyn sodium, acetylcysteine sodium, and budesonide.

METHODS

We mixed one dose of levalbuterol inhalation solution concentrate (1.25 mg/0.5 mL) with one dose of ipratropium bromide (0.5 mg/2.5 mL), cromolyn sodium (20 mg/2 mL), acetylcysteine sodium (1,000 mg/5 mL), or budesonide (0.5 mg/2 mL). Immediately after mixing the 2 drugs (time zero [T(0)]), and again after 30 min at room temperature (T(30)), we visually inspected the admixtures, measured their pH, and conducted high-pressure liquid chromatography (HPLC).

RESULTS

There was no evidence of physical incompatibility with these drugs combinations. With all the admixtures, both drugs were chemically stable for at least 30-min. Admixture pH had not changed significantly at T(30). Drug recovery was 93.2-102.6% of the initial or control values.

CONCLUSIONS

The 2-drug admixtures we studied were compatible for at least 30 min at room temperature.

Improved Efficiency of Budesonide Nebulization Using Surface-Active Agents

Our aim was to improve the efficiency of nebulised budesonide using surface-active agents. Cationic, anionic, and nonionic detergents were added to commercial budesonide suspension, and the particle size distribution during nebulization was measured using both cascade impaction and laser diffraction. Our results showed that the emitted dose was increased after addition of cationic (p < 0.001) and nonionic detergents (p < 0.01) compared with the commercial formulation alone. The respirable fraction was increased for all detergent formulations (p < 0.001) compared with the commercial formulation. We concluded that cationic and nonionic detergent increased the total output of budesonide from the Sidestream. All detergent formulations increased the respirable fraction of nebulized budesonide.

Influence of Impactor Operating Flow Rate on Particle Size Distribution of Four Jet Nebulizers

When a nebulizer is evaluated by the Andersen Cascade Impactor (ACI), the flow rate is generally maintained at 28.3 L/min, as recommended by the manufacturer. However, the nebulizer flow rate that a patient inhales is only around 18 L/min. Because the drive flow of a nebulizer is approximately 6-8 L/min, the nebulized drug is mixed with outside air when delivered. Evaluating impactor performance at the 28.3 L/min flow rate is less than ideal because an additional 10 L/min of outside air is mixed with the drug, thereby affecting the drug size distribution and dose before inhalation and deposition in the human lung. In this study we operated the ACI at an 18.0 L/min flow rate to test whether the effect of the changing ambient humidity was being exaggerated by the 28.3 L/min flow rate. The study was carried out at three different relative humidity levels and two different impactor flow rates with four commercially available nebulizers. The mass median aerodynamic diameter (MMAD) and the geometric standard deviation (GSD) of the droplets were found to increase when the impactor was operated at a flow rate of 18 L/min compared to that of 28.3 L/min. The higher MMAD and GSD could cause the patient to inhale less of the drug than expected if the nebulizer was evaluated by the ACI at the operating flow rate of 28.3 L/min.

Preparation of Budesonide-Poly (Ethylene Oxide) Solid Dispersions Using Supercritical Fluid Technology

The purpose of this study was to investigate the possibility of preparing solid dispersions of the poorly soluble budesonide by supercritical fluid (SCF) technique, using poly (ethylene oxide) (PEO) as a hydrophilic carrier. The budesonide-PEO solid dispersions were prepared, using supercritical carbon dioxide (SC CO(2)) as the processing medium, and characterized by scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), solubility test and dissolution test in order to understand the influence of the SCF process on the physical status of the drug. The endothermic peak of budesonide in the SCF-treated mixtures was significantly reduced, indicating that budesonide was in amorphous form inside the carrier system. This was further confirmed by SEM and PXRD studies. The enhanced dissolution rates of budesonide were observed from SCF-treated budesonide-PEO mixtures. The amorphous characteristic of the budesonide, the better mixing of drug and PEO powders in the presence of SC CO(2), together with the improved wettability of the drug in PEO, produced a remarkable enhancement of the in vitro drug dissolution rate. Thus, budesonide-PEO solid dispersions with enhanced dissolution rate can be prepared using organic solvent-free SCF process.

Chitosan coated Ca–alginate microparticles loaded with budesonide for delivery to the inflamed colonic mucosa

Using a novel one-step spray-drying process uncoated and Eudragit S 100 coated chitosan-Ca-alginate microparticles efficiently loaded with budesonide (BDS), with bioadhesive and controlled release properties in GIT, were prepared. Microparticles were spherical with mean particle size of 4.05-5.36 microm, narrow unimodal distribution and positive surface charge. A greater extent of calcium chloride limited the swelling ratio of beads, while swelling behaviour of coated beads was mainly determined by properties of enteric coating. Comparing the release profiles of formulations, under different pH conditions, influence of polymer properties and concentration of cross-linker on the rate and extent of drug release was evident. Coating has successfully sustained release of BDS in buffers at pH 2.0 and 6.8, while providing potential for efficient release of BDS at pH 7.4. Release data kinetics indicated influence of erosion and biodegradation of polymer matrix on drug release from microparticles. Prepared formulations were stable for 12 months period at controlled ambient conditions. In conclusion coated microparticles prepared by one-step spray-drying procedure could be suitable candidates for oral delivery of BDS with controlled release properties for local treatment of inflammatory bowel diseases.

Multilayer PVA adsorption onto hydrophobic drug substrates to engineer drug-rich microparticles

Despite the availability of numerous crystal engineering techniques, generating drug-rich microparticles with a predetermined size, morphology and crystallinity still represents a significant challenge. A microparticle manufacturing method has recently been developed that attempts to 'shield' the physicochemical properties of micronised drugs by the application of a microfine polymer coating. The aims of this study were to investigate the nature of the drug-polymer interactions and determine the effects of this manufacturing strategy upon release of the drug from the microparticles. The adsorption of poly(vinyl alcohol) (PVA) on the micronised hydrophobic drug surface was found to reach equilibrium between 23 and 27 h. The Freundlich isotherm model was shown to give the most accurate fit to the experimental data and thus multilayer adsorption was assumed. The adsorptive capacity (1/n) was specific to the substrate and PVA grade. An increase in the PVA (%) hydrolysis value caused 1/n to increase from 0.76 to 1.05 using budesonide and from 0.31 to 0.79 when betamethasone valerate (BMV) was used. Increasing the molecular weight of the adsorbing polymer caused a reduction in the strength of PVA-adsorbate interaction when budesonide was used as the substrate (from 0.76 to 0.59), whereas a three-fold increase (from 0.31 to 0.86) was achieved when the BMV substrate was employed. A proportion of the adsorbed polymer was shown to remain associated with the substrate during the spray-drying process and the polymer coating resulted in a significantly higher (p<0.05, ANOVA) amount of drug release in 60 min (ca. 100%) compared to budesonide alone.

Low-voltage electrohydrodynamic (EHD) spray drying of respirable particles

Spray drying is a widely used process to produce pharmaceutical powders. In traditional spray drying, the particle size distribution is wide and not well controlled. Using EHD atomization for spray drying offers a possibility to tailor the particle size and morphology. In conventional EHD spray drying, the generated particles are charged and need to be discharged to avoid Rayleigh breakup. Discharging adds complexity to the process and eliminates the possibility to collect the powder using an electric field. The present work describes a novel EHD spray drying setup based on a low-voltage nozzle. The low-voltage nozzle imparts moderate charge to the droplets, which makes discharging unnecessary. The charged particles can be controlled and collected by using an auxiliary electric field. The EHD spray dryer has been characterized in terms of particle size, particle morphology, process output, and yield. The size distribution of the generated particles is very narrow. Both porous and completely spherical particles can be produced. The yield of small-scale bench-top equipment was 20%, which is similar to the yield of a small-scale conventional spray dryer. The effective output with five nozzles was 75 mg/hr of dry powder. Because of the repelling forces associated with the unipolarly charged droplets, the number of nozzles can be increased without risking coalescence.

The ester group: how hydrofluoroalkane-philic is it?

Pressurized metered-dose inhalers (pMDIs) have been recognized as potential devices for the delivery of systemically acting drugs, including biomolecules, to and through the lungs. Therefore, the development of novel excipients capable of imparting stability to suspension formulations in hydrofluoroalkane (HFA) propellants is of great relevance because many of the drugs of interest are poorly soluble in HFAs. In this work, we use ab initio calculations and chemical force microscopy (CFM) to determine the HFA-philicity of the biodegradable and biocompatible ester moiety quantitatively. The complementary information obtained from the binding energy calculations and adhesion force measurements are used to gain microscopic insight into the relationship between the chemistry of the moiety of interest and its solvation in HFA. A lactide (LA)-based copolymer surfactant was synthesized and characterized, and its ability to stabilize a dispersion of micronized budesonide in HFA227 was demonstrated. These results corroborate the ab initio calculations and CFM and show that the LA-based moiety is a suitable candidate for enhancing the stability of dispersions in HFA-based pMDIs.

Compressor/nebulizers differences in the nebulization of corticosteroids. The CODE study (Corticosteroids and Devices Efficiency)

BACKGROUND

Nebulization is a common method of medical aerosol generation and it is largely used by adults and children all over the world, both for emergency treatment of acute illness and for long-term home treatment of lung diseases. The aim of this study was to determine the differences in nebulization of inhaled corticosteroids among four representative types of compressor/nebulizers.

METHODS

Twelve compressor/jet nebulizers from four commercial sources were studied (three for each type): Clenny (MEDEL), Turbo Boy/LC Plus (PARI), Nebula Nuovo/MB5 (MARKOS MEFAR) and Maxaer (ARTSANA) compressor/Sidestream (Medic-Aid Ltd.) nebulizer. We compared the required time for the treatment (nebulization time), output/minutes, compressor pressures, and aerosol characteristics of inhaled corticosteroids: Beclomethasone dipropionate, Flunisolide, Fluticasone propionate and Budesonide.

RESULTS

Nebulization Times showed a significant difference between nebulizer and inhaled corticosteroids for Clenny, Turbo Boy, and Maxaer. A considerable difference in the output of nebulized drugs was observed through the compressors/nebulizers. MMAD of all inhaled corticosteroids was significantly different among the four nebulizers. The percentage of particles <5 microm (respirable range) was high for all devices with beclomethasone and budesonide (> 90%), whereas with flunisolide was good only for Clenny (98.8%) and Maxaer (96.3%), and with fluticasone only for Clenny (98%), Turbo Boy (99.1%), and Maxaer (86%). Also percentage of particles <2 microm showed significant variability among the devices.

CONCLUSIONS

Our results clearly demonstrate that compressor/nebulizer unit plays a key role in the effectiveness of the treatment during inhaled corticosteroid therapy, and that several differences exist in the performance of the different nebulizers studied. Therefore, the device has the same importance of the compound to reach the best clinical response in the inflammatory diseases of the lower airways.

Prevention of peritoneal adhesions with an in situ cross-linkable hyaluronan hydrogel delivering budesonide

Peritoneal adhesions are tissue connections that form within the abdominopelvic cavity following surgery or other injuries. They can cause major medical complications. Barrier devices and pharmacological agents have been used to prevent adhesion formation, with mixed success. We hypothesize that an adhesion barrier which also delivers anti-adhesion drugs can address both physical and physiological causes for adhesion formation. Here, we describe an in situ cross-linking hyaluronan hydrogel (barrier device) containing the glucocorticoid receptor agonist budesonide. Budesonide was chosen because of the known role of inflammation in adhesion formation, hyaluronan because of its known biocompatibility in the peritoneum. The system, consisting of two cross-linkable precursor liquids, was applied using a double-barreled syringe, forming a flexible and durable hydrogel in less than 5 s. We applied this formulation or controls to the injured sites after the second injury in a severe repeat sidewall defect-cecum abrasion model of peritoneal adhesion formation in the rabbit. Large adhesions (median area 15.4 cm(2)) developed in all saline-treated animals. Adhesion formation and area were slightly mitigated in animals treated with budesonide in saline (median area 5.0 cm(2)) or the hydrogel without budesonide (median area 4.9 cm(2)). The incidence and area of adhesions were dramatically reduced in animals treated with budesonide in the hydrogel (median area 0.0 cm(2)). In subcutaneous injections in rats, budesonide in hydrogel reduced inflammation compared to hydrogel alone. In summary, budesonide in a hyaluronan hydrogel is easy to use and highly effective in preventing adhesions in our severe repeated injury model. It is a potentially promising system for post-surgical adhesion prevention, and suggests that the effectiveness of barrier devices can be greatly enhanced by concurrent drug delivery.

Transformation of pharmaceutical compounds upon milling and comilling: the role of T(g)

Milling is a usual process used in the course of drug formulation, which however may change the physical nature of the end product. The diversity of the transformations of organic compounds upon milling has been widely demonstrated in the pharmaceutical literature. However, no effort has still been devoted to study the correlation between the nature of the transformation and the milling conditions. Results clarifying such transformations are shortly reviewed with special attention paid to the temperature of milling. The importance of the position of the glass transition temperature compared with that of milling is demonstrated. It is shown that decreasing the milling temperature leads to an increase of the amorphization tendency whereas milling above T(g) can produce a crystal-to-crystal transformation between polymorphic varieties. These observations contradict the usual suggestion that milling transforms the physical state only by a heating effect which induces a local melting. Equilibrium thermodynamics does not seem appropriate for describing the process. The driven alloys concept offers a more rational framework to interpret the effect of the milling temperature. Other results are also presented, which demonstrate the possibility for milling to form low temperature solid-state alloys that offer new promising ways to stabilize amorphous molecular solids.

Inhibition of allergen-induced airway remodelling by tiotropium and budesonide: a comparison

Chronic inflammation in asthma and chronic obstructive pulmonary disease drives pathological structural remodelling of the airways. Using tiotropium bromide, acetylcholine was recently identified as playing a major regulatory role in airway smooth muscle remodelling in a guinea pig model of ongoing allergic asthma. The aim of the present study was to investigate other aspects of airway remodelling and to compare the effectiveness of tiotropium to the glucocorticosteroid budesonide. Ovalbumin-sensitised guinea pigs were challenged for 12 weeks with aerosolised ovalbumin. The ovalbumin induced airway smooth muscle thickening, hypercontractility of tracheal smooth muscle, increased pulmonary contractile protein (smooth-muscle myosin) abundance, mucous gland hypertrophy, an increase in mucin 5 subtypes A and C (MUC5AC)-positive goblet cell numbers and eosinophilia. It was reported previously that treatment with tiotropium inhibits airway smooth muscle thickening and contractile protein expression, and prevents tracheal hypercontractility. This study demonstrates that tiotropium also fully prevented allergen-induced mucous gland hypertrophy, and partially reduced the increase in MUC5AC-positive goblet cell numbers and eosinophil infiltration. Treatment with budesonide also prevented airway smooth muscle thickening, contractile protein expression, tracheal hypercontractility and mucous gland hypertrophy, and partially reduced MUC5AC-positive goblet cell numbers and eosinophilia. This study demonstrates that tiotropium and budesonide are similarly effective in inhibiting several aspects of airway remodelling, providing further evidence that the beneficial effects of tiotropium bromide might exceed those of bronchodilation.

Crystal structure changes of gamma-cyclodextrin after the SEDS process in supercritical carbon dioxide affect the dissolution rate of complexed budesonide

PURPOSE

The present study describes the crystal structure changes of gamma-cyclodextrin (gamma-CD) during the solution enhanced dispersion by supercritical fluids (SEDS) process and its effect on dissolution behaviour of complexed budesonide.

MATERIALS AND METHODS

gamma-CD solution (10 mg/ml in 50% ethanol) was pumped together with supercritical carbon dioxide through a coaxial nozzle with or without a model drug, budesonide (3.3 mg/ml). The processing conditions were 100 b and 40, 60 or 80 degrees C. gamma-CD powders were characterised before and after vacuum-drying (2-3 days at RT) with XRPD, SEM and NMR. Budesonide/gamma-CD complexation was confirmed with DSC and XRPD. The dissolution behaviour of complexed budesonide was determined in aqueous solution (1% gamma-CD, 37 degrees C, 100 rpm).

RESULTS

During the SEDS process (100 b, 40 and 60 degrees C), gamma-CD and budesonide/gamma-CD complexes crystallized in a tetragonal channel-type form. The vacuum-drying transformed crystalline gamma-CD into amorphous form while the complexes underwent a tetragonal-to-hexagonal phase transition. The increase in the processing temperature decreased the crystallinity of gamma-CD. At 80 degrees C, amorphous gamma-CD was obtained while the complexes crystallized in a hexagonal channel-type form. The dissolution behaviour of budesonide/gamma-CD complexes was dependent on their crystal structure: the tetragonal form dissolved faster than the hexagonal form.

CONCLUSIONS

The crystal structure of gamma-CD and subsequently, the dissolution rate of complexed budesonide, can be modified with the processing conditions.

[Factors influencing the content of residual tert-butyl alcohol in cyclodextrin complex prepared by lyophilization cosolvent system]

In order to minimize the residual tert-butyl alcohol (TBA) level in cyclodextrin complex prepared by freeze drying TBA/water cosolvent system, the formulation and lyophilization procedure that may influence the residual TBA was studied. Residual TBA in freeze dried cyclodextrin complex was determined by gas chromatography. The significant formulation and processing factors that influence residual TBA were identified by adjusting the initial TBA concentration in cosolvent, selecting cyclodextrin type (beta-cyclodextrin or hydroxypropyl beta-cyclodextrin), changing sample volume in flasket, altering freezing mode (fast freezing or slow freezing) and modifying the duration of secondary drying. The results show that the amorphous cyclodextrin material (hydroxypropyl beta-cyclodextrin), initial low TBA concentration in cosolvent and fast freezing would lead to high TBA residue in cyclodextrin complex, annealing was effective in reducing the residual TBA. The duration of secondary drying had no distinct effect on residual TBA. It is concluded that in order to reduce residual TBA in cyclodextrin complex prepared by lyophilization monophase solution, the initial TBA concentration in cosolvent should be higher than the crystal formation concentration, the appropriate cyclodextrin type and freeze drying processing should be choosen.

Chitosan-based controlled porosity osmotic pump for colon-specific delivery system: Screening of formulation variables and in vitro investigation

A microbially triggered colon-targeted osmotic pump (MTCT-OP) has been studied. The gelable property at acid condition and colon-specific biodegradation of chitosan were used to: (1) produce the osmotic pressure, (2) form the drug suspension and (3) form the in situ delivery pores for colon-specific drug release, respectively. The scanning electron microscopy (SEM) study and the calculation of membrane permeability were applied to elucidate the mechanism of MTCT-OP. The effects of different formulation variables, including the level of pH-regulating excipient (citric acid) and the amount of chitosan in the core, the weight gain of semipermeable membrane and enteric-coating membrane, and the level of pore former (chitosan) in the semipermeable membrane, have been studied. Results of SEM showed that the in situ delivery pores could be formed in predetermined time after coming into contact with dissolution medium, and the number of pore was dependent on the initial level of pore former in the membrane. The amount of budesonide release was directly proportional to the initial level of pore former, but inversely related to the weight of semipermeable membrane. The effects of variations in the level of citric acid and chitosan in the core formulation on drug release were studied. The different levels of enteric-coating membrane could prevent cellulose acetate membrane (containing chitosan as pore former) from forming pore or rupture before contact with simulated colonic fluid, but had no effect on the drug release. Budesonide release from the developed formulation was inversely proportional to the osmotic pressure of the release medium, confirming that osmotic pumping was the major mechanism of drug release. These results showed that MTCT-OP based on osmotic technology and microbially triggered mechanism had a high potential for colon-specific drug delivery.

[Preparation of budesonide-poly (ethylene oxide) solid dispersions using supercritical carbon dioxide and in vitro evaluation]

An application of supercritical fluids technology for processing of budesonide-poly (ethylene oxide) solid dispersions was presented. The correlations of the operation parameters in the preparation process were studied. Solid dispersions of budesonide in poly (ethylene oxide) were prepared using a static method for supercritical carbon dioxide and characterized by powder X-ray diffractometry, differential scanning calorimetry, intrinsic dissolution, and in vitro dissolution. It was found that the optimum condition of solid dispersions formation was as follows: temperature, 40 degrees C ; pressure, 20 MPa; the ratio of budesonide and poly (ethylene oxide) , 1: 10. Drug existed in amorphous state in hydrophilic poly (ethylene oxide) carriers and intrinsic solubility and dissolution rates were significantly enhanced. The mechanism of the enhanced dissolution may be attributed to the amorphous character of the budesonide, improvement of the wettability of the hydrophobic budesonide, together with the formation of hydrogen bond of budesonide and hydrophilic poly (ethylene oxide). The supercritical fluids process can be used as an alternative method for preparation of solid dispersions.

The effect of carrier surface treatment on drug particle detachment from crystalline carriers in adhesive mixtures for inhalation

In this study, the effect of lactose carrier surface treatment on drug particle detachment during inhalation has been investigated. Crystals of marketed brands of alpha lactose monohydrate brands normally exhibit a certain surface rugosity and contain natural fines and impurities on their surface, which influence the drug-to-carrier interaction in adhesive mixtures for inhalation. Submersion treatment may change these surface characteristics. Two different sieve fractions (63-90 and 250-355microm) were submerged in mixtures of ethanol and water (96 and 80% v/v, respectively). Microscopic observation and laser diffraction analysis revealed that neither the shape nor the size of the carrier particles was changed by the submersion treatment. However, the specific surface area and the amount of impurities appeared to decrease substantially after submersion, and the magnitude of the decrease was different for the different ethanol-water mixtures. The reduction in specific surface area was attributed particularly to the removal of the adhering lactose fines from the carrier surface. Mixtures with budesonide (in a wide range of carrier payloads) were prepared before and after treatment. Drug particle detachment from the various mixtures was studied with a sieve test and with a cascade impactor analysis at 30 and 60l/min. Two different types of inhalers were used, one generating lift- and drag-forces (ISF inhaler) and one generating inertial forces (test inhaler), respectively. The cascade impactor and sieve test experiments showed that an increase in carrier surface smoothness results in a reduced drug particle detachment during inhalation, which was independent of the type of inhaler used. This reduction could be attributed to the removal of the adhering lactose fines which may provide shelter for the drug particles from press-on forces during mixing.

In vitro investigation of drug particulates interactions and aerosol performance of pressurised metered dose inhalers

PURPOSE

To determine a relationship between adhesive and cohesive inter-particulate forces of interactions and in vitro performance in pressurised metered dose inhalers (pMDIs) suspension formulations.

METHODS

Interparticulate forces of salbutamol sulphate (SS), budesonide (BUD) and formoterol fumarate dihydrate (FFD) were investigated by in situ atomic force microscopy (AFM) in a model propellant 2H, 3H perfluoropentane (HPFP). Experimental data were analysed using the recently developed cohesive/adhesive analysis method (CAB) and compared with in vitro deposition performances in pMDIs systems using Andersen cascade impactor (ACI).

RESULTS

The in vitro investigation suggested that the micronised drug materials had significantly different aerosolisation profiles when manufactured as single or combination formulations. In general, the greatest significant differences were observed between SS single drug and SS-BUD and SS-FFD combinations. Analysis of the in vitro performance for the SS only formulation suggested that the cohesive nature of SS (as predicted by the CAB and observed with AFM) led to tightly bound flocs that did not fully deaggregate upon aerosolisation.

CONCLUSIONS

It is suggested that the relationship between interparticulate interactions and in vitro performance of pMDIs suspension systems, when compared to direct measurement of the adhesion/cohesion forces, indicated good correlation. This approach may be useful in expediting the development of pMDI formulation and predicting performance.

Preparation of budesonide/γ‐cyclodextrin complexes in supercritical fluids with a novel SEDS method

The aim was to investigate if solid drug/cyclodextrin complexes could be produced in a single-step process with a solution enhanced dispersion by supercritical fluids (SEDS) method. Budesonide and gamma-cyclodextrin (CD) solutions (50% or 99.5% ethanol) were pumped from the same (conventional method) or separate (modified method) containers together with supercritical carbon dioxide through a coaxial nozzle into a particle formation chamber. The pressure was maintained at 100, 150 or 200 bar with a temperature of 40, 60 or 80 degrees C. SEDS-processed powders were characterised with HPLC, DSC and XRPD for budesonide content, complexation and crystallinity. The budesonide dissolution rate was determined in 1% gamma-CD aqueous solution. Solid, white budesonide/gamma-CD complex particles were formed using the conventional and modified SEDS processes. The complexation efficiency was dependent on the processing conditions. For example, with the conventional method (100 bar, 60 degrees C) the yield of the powder was 65+/-12% with 0.14+/-0.02 mg budesonide/mg powder, corresponding to 1:2 drug:CD molar ratio. The dissolution rate of this complexed budesonide (93+/-2% after 15 min) was markedly higher compared to unprocessed micronised budesonide (41+/-10%) and SEDS-processed budesonide without CD (61+/-3%). As a conclusion, SEDS is a novel method to produce solid drug/CD complexes in a single-step process.

Pharmacoscintigraphic evaluation of lipid dry powder budesonide formulations for inhalation

Lung deposition of new formulations of budesonide, using solid lipid microparticles (SLmP) as a pharmaceutically acceptable filler and carrier for inhalation aerosols, and administered from a dry powder inhaler (Cyclohaler), were compared with that from Pulmicort Turbuhaler. Six healthy volunteers took part in a three-way randomized cross-over study, and inhaled a nominal dose of 400 microg budesonide, labelled with 99mTc, on each study day. Lung deposition was determined by gamma scintigraphy and by a pharmacokinetic method. The percentage of dose (SD) in the whole lung was 49.9 (3.7)% for the lipidic matricial form (M) and 62.8 (4.9)% for the lipidic physical blend formulation (PB). These results corresponded well with the in vitro fine particle assessment. In comparison with data recorded in literature for in vivo deposition obtained with Pulmicort Turbuhaler, it was estimated that lung deposition was 1.5 and 2.0 times higher for the M and PB formulations, respectively. Furthermore, the relative drug availability obtained from the pharmacokinetic evaluation, expressed as the percentage of pulmonary absorption of the comparator product, was 154% and 220% for M and PB, respectively. The results of the present study indicate that pulmonary administration using SLmP gives a prominent and significant increase in budesonide lung deposition.

Detection of budesonide in human urine after inhalation by liquid chromatography-mass spectrometry

Budesonide, a corticosteroid frequently used in the treatment of asthma, is most often administered via inhalation. Its use in sports is allowed when medically necessary. A fast, sensitive and accurate LC-MS method was developed and validated for the quantification of budesonide and its major metabolite 16alpha-hydroxyprednisolone in urine samples after inhalation of a metered dose (Pulmicort-Turbohaler 200). Sample preparation consists of an alkaline liquid-liquid extraction with ethyl acetate. Analysis was performed using liquid chromatography-tandem mass spectrometry with electrospray ionization (ESI). The method was linear in the range of 5-100 and 0.5-10ng/mL for 16alpha-hydroxyprednisolone and budesonide, respectively. The limits of quantification were 5ng/ml for 16alpha-hydroxyprednisolone and 0.5ng/mL for budesonide. The accuracy ranged from 2.2 to 3.5% for 16alpha-hydroxyprednisolone and from 0.8 to 16.4% for budesonide. After administration of 200microg of budesonide to five healthy volunteers budesonide could not be detected in any urine sample whereas 16alpha-hydroxyprednisolone was detectable up to 12h post-administration.

Microencapsulation of drugs by electro-hydro-dynamic atomization

This paper presents practical aspects of production of polymeric particles loaded with a drug by electro-hydro-dynamic atomization (EHDA). Particles were produced from paracetamol (4-acetamidophenol), budesonide and polylactic acid containing Taxol (paclitaxel). Influence of solvent type and evaporation rate, as well as other polymers additives on particle morphology and drug release rate is demonstrated. It is shown that quickly evaporating solvents have a tendency to form hollow particles. Drug release rate from hollow particles is substantially higher than from solid ones. Addition of water-soluble polymer, polyethylene glycol, also increases drug release rate.

Preparation and in vitro evaluation of lipidic carriers and fillers for inhalation

The present study relates to compositions of solid lipidic microparticles (SLmP), composed of biocompatible phospholipids and cholesterol, and their use as carriers or as fillers delivering drugs directly to the lungs via a dry powder inhaler (DPI). SLmP were obtained by spray-drying and were formulated as lipidic matrices entrapping budesonide or as physical blends (drug carrier). They were developed in order to improve the delivery of the active drug by the pulmonary route. The SLmP were evaluated for their physical characteristics and in vitro deposition measurements were performed using the Multi-stage Liquid Impinger (MsLI). The Pulmicort Turbuhaler DPI (AstraZeneca) was used as a comparator product. The SLmP appeared to be spherical low-density material characterized by a smooth surface. The mass median diameters (D(0.5)), and the volume mean diameters (D[4,3]) were tiny and ranged from 1.7 to 3.1 microm and from 2.0 to 3.9 microm, respectively. The SLmP formulations, delivered by the Cyclohaler inhaler, were found to emit a fine particle dose (FPD) of 93-113 microg, which is very promising comparing to the FPD (68 microg) delivered by the Pulmicort Turbuhaler.

[Determination of liposome/water partition coefficients of salmeterol and budesonide and study on their influencing factors]

AIM

The liposome/water partition coefficients of salmeterol and budesonide between aqueous phase and liposomes were determined and the factors that influence their partition coefficients were studied, the mechanism of interaction between the two drugs and phospholipid bilayer was elucidated.

METHODS

The liposome/water partition coefficients of the two drugs were determined by equilibrium dialysis technique. The change of the partition coefficients of the two drugs along with liposome composition and medium was also studied.

RESULTS

The partition coefficients of the two drugs decreased with the increase of cholesterol content and saturation of phospholipid used. The liposome/water partition coefficient of salmeterol increased with the increase of liposome surface negative charge, medium pH and ionic strength, while the liposome surface charge, medium pH and ionic strength had no distinct effect on the liposome/water partition coefficient of budesonide.

CONCLUSION

The liposome/water partition coefficient of drug was affected by the type, saturation of phospholipid used in liposome preparation, the cholesterol content and surface charge of liposome, as well as the pH and ionic strength of medium also have effect on the liposome/water partition coefficient of drug. Accordingly, in order to reflect the actual partition of drug in biological membrane, the determination condition including liposome composition and medium should be similar to the biological membrane.

High performance liquid chromatography assay method for simultaneous quantitation of formoterol and budesonide in Symbicort Turbuhaler

A sensitive and rapid high performance liquid chromatography method has been developed and used for the simultaneous determination of formoterol and budesonide in Symbicort Turbuhaler when assessing the aerodynamic characteristics of the emitted dose using Pharmacopoeial methods. This capability results in both time and cost saving. The mobile phase composition was acetonitrile-5 mM sodium dihydrogen orthophosphate, pH 3 (60: 40% v/v), and was passed at 1.5 ml min(-1) through a C18 column with a UV detection (wavelength 214 nm). The method was shown to give good analytical performance in terms of linearity, precision (using phenylpropanolamine as an internal standard), sensitivity and solution stability. The intra-day precision for both formoterol and budesonide were 0.75% and 1.11%, respectively (n = 10). The limit of quantitation for formoterol was 10 microgL(-1) and for budesonide was 120 microgL(-1), and the limit of detection were 3 and 30 microgL(-1), for both formoterol and budesonide, respectively. The method has been applied to determine the content of the emitted dose and the fine particle dose of Symbicort Turbuhaler.

Design and in vitro performance testing of multiple air classifier technology in a new disposable inhaler concept (Twincer) for high powder doses

Dry powder inhalation of antibiotics in cystic fibrosis (CF) therapy may be a valuable alternative for wet nebulisation, because it saves time and it improves lung deposition. In this study, it is shown that the use of multiple air classifier technology enables effective dispersion of large amounts of micronised powder (up to 25mg). X(50)-values of the aerosol from laser diffraction analysis obtained with the Twincer disposable inhaler concept (containing multiple air classifier technology) are practically the same as that for the pure drug in the range of dose weights between 0 and 25mg. Only for the highest dose weights, a minor fraction (5-7.5%) of small agglomerates (5-15microm) is released from the inhaler. Moreover, the size distribution of the aerosol is practically the same at 1 and 4kPa. Cascade impactor results confirm the good performance of the multiple classifier concept. Unprocessed micronised particles or soft spherical agglomerates can be used, and special particle engineering processes are not necessary. Only a minor fraction of coarse sweeper crystals in the formulation is desired to reduce the total inhaler losses for colistin sulfomethate to less than 5-6% at 4kPa. The classifiers can be designed to retain these crystals with more than 95% efficiency.

Air classifier technology (ACT) in dry powder inhalation

In this study, the design of a multifarious classifier family for different applications is described. The main design and development steps are presented as well as some special techniques that have been applied to achieve preset objectives. It is shown by increasing the number of air supply channels to the classifier chamber (from 2 to 8), that the fine particle losses from adhesion onto the classifier walls can be reduced from 75% to less than 5% of the real dose for soft (spherical) agglomerates. By applying a bypass flow that is arranged as a co-axial sheath of clean air around the aerosol cloud from the classifier, the airflow resistance of the classifier can be controlled over a relatively wide range of values (0.023-0.041 kPa(0.5) min l(-1)). This, without affecting the fine particle dose or increasing the fine particle losses in the inhaler. Moreover, the sheath flow can be modelled to reduce the depositions in the induction port to the cascade impactor or in the patient's mouth, which are the result of back flows in these regions. The principle of powder induced pressure drop reduction across a classifier enables assessment of the amount of powder in the classifier at any moment during inhalation, from which classifier loading (from the dose system) and discharge rates can be derived. This principle has been applied to study the residence time of a dose in the classifier as function of the carrier size fraction and the flow rate. It has been found that this residence time can be controlled in order to obtain an optimal balance between the generated fine particle fraction and the inhalation manoeuvre of the patient. A residence time between 0.5 and 2 s at 60 l/min is considered favourable, as this yields a high fine particle dose (depending on the type of formulation used) and leaves sufficient inhaled volume for particle transport into the deep lung.

Air classifier technology (ACT) in dry powder inhalation

In this study, the in vitro fine particle deposition from a multi dose dry powder inhaler (Novolizer) with air classifier technology has been investigated. It is shown that different target values for the fine particle fraction (fpf<5 microm) of the same drug can be achieved in a well-controlled way. This is particularly relevant to the application of generic formulations in the inhaler. The well-controlled and predictable fpf is achieved through dispersion of different types of formulations in exactly the same classifier concept. On the other hand, it is shown that air classifier-based inhalers are less sensitive to the carrier surface and bulk properties than competitive inhalers like the Diskus. For 10 randomly selected lactose carriers for inhalation from four different suppliers, the budesonide fpf (at 4 kPa) from the Novolizer varied between 30 and 46% (of the measured dose; R.S.D.=14.2%), whereas the extremes in fpf from the Diskus dpi were 7 and 44% (R.S.D.=56.2%) for the same formulations. The fpf from a classifier-based inhaler appears to be less dependent of the amount of lactose (carrier) fines (<15 microm) in the mixture too. Classifier-based inhalers perform best with coarse carriers that have relatively wide size distributions (e.g. 50-350 microm) and surface discontinuities inside which drug particles can find shelter from press-on forces during mixing. Coarse carrier fractions have good flow properties, which increases the dose measuring accuracy and reproducibility. The fpf from the Novolizer increases with increasing pressure drop across the device. On theoretical grounds, it can be argued that this yields a more reproducible therapy, because it compensates for a shift in deposition to larger airways when the flow rate is increased. Support for this reasoning based on lung deposition modelling studies has been found in a scintigraphic study with the Novolizer. Finally, it is shown that this inhaler produces a finer aerosol than competitor devices, within the fpf<5 microm, subfractions of particles (e.g. <1, 1-2, 2-3, 3-4 and 4-5 microm) are higher.

Micro- and nanoparticulates

OBJECTIVES

Pharmacotherapeutics has begun to play an increasingly important role in the management of patients with neovascular age-related macular degeneration (AMD). Because micro- and nano-particulates are currently being evaluated as a potential drug-delivery option for AMD patients, the purpose of this analysis was to describe how micro- and nano-particulates have been used experimentally and what their potential clinical applications may be.

FINDINGS

Micro- and nano-particulates have been used primarily on a pre-clinical basis as new drug-delivery devices in experimental models of neovascular AMD.

CONCLUSIONS

It is likely that micro- and nano-particulates will become an important component of targeted clinical pharmacotherapeutics in patients with neovascular AMD.