HIV envelope antibodies and TLR7 agonist partially prevent viral rebound in chronically SHIV-infected monkeys.

A key challenge for the development of a cure to HIV-1 infection is the persistent viral reservoir established during early infection. Previous studies using Toll-like receptor 7 (TLR7) agonists and broadly neutralizing antibodies (bNAbs) have shown delay or prevention of viral rebound following antiretroviral therapy (ART) discontinuation in simian-human immunodeficiency virus (SHIV)-infected rhesus macaques. In these prior studies, ART was initiated early during acute infection, which limited the size and diversity of the viral reservoir. Here we evaluated in SHIV-infected rhesus macaques that did not initiate ART until 1 year into chronic infection whether the TLR7 agonist vesatolimod in combination with the bNAb PGT121, formatted either as a human IgG1, an effector enhanced IgG1, or an anti-CD3 bispecific antibody, would delay or prevent viral rebound following ART discontinuation. We found that all 3 antibody formats in combination with vesatolimod were able to prevent viral rebound following ART discontinuation in a subset of animals. These data indicate that a TLR7 agonist combined with antibodies may be a promising strategy to achieve long-term ART-free HIV remission in humans.

Fiber chromatographic enabled process intensification increases monoclonal antibody product yield.

The most straightforward method to increase monoclonal antibody (mAb) product yield is to complete the purification process in less steps. Here, three different fiber chromatographic devices were implemented using a holistic approach to intensify the mAb purification process and increase yield. Fiber protein A (proA) chromatography was first investigated, but traditional depth filtration was not sufficient in reducing the contaminant load as the fiber proA device prematurely fouled. Further experimentation revealed that chromatin aggregates were the most likely reason for the fiber fouling. To reduce levels of chromatin aggregates, a chromatographic clarification device (CCD) was incorporated into the process, resulting in single-stage clarification of harvested cell culture fluid and reduction of DNA levels. The CCD clarified pool was then successfully processed through the fiber proA device, fully realizing the productivity gains that the fiber technology offers. After the proA and viral inactivation neutralization (VIN) hold step, the purification process was further intensified using a novel single-use fiber-based polishing anion exchange (AEX) material that is capable of binding both soluble and insoluble contaminants. The three-stage fiber chromatographic purification process was compared to a legacy five-step process of dual-stage depth filtration, bead-based proA chromatography, post-VIN depth filtration, and bead-based AEX chromatography. The overall yield from the five-step process was 60%, while the fiber chromatographic-enabled intensified process had an overall yield of 70%. The impurity clearance of DNA and host cell protein (HCP) for both processes were within the regulatory specification (<100 ppm HCP, <1 ppb DNA). For the harvest of a 2000 L cell culture, the intensified process is expected to increase productivity by 2.5-fold at clarification, 50-fold at the proA step, and 1.6-fold in polishing. Relative to the legacy process, the intensified process would reduce buffer use by 1088 L and decrease overall process product mass intensity by 12.6%.

PD-1 Blockade and TLR7 Activation Lack Therapeutic Benefit in Chronic Simian Immunodeficiency Virus-Infected Macaques on Antiretroviral Therapy.

Antiretroviral therapy (ART) limits human immunodeficiency virus 1 (HIV-1) replication but does not eliminate the long-lived reservoir established shortly after viral acquisition. A successful HIV cure intervention necessitates either elimination or generation of long-term immune control of the persistent viral reservoir. Immune modulating strategies in conjunction with ART hold promise for achieving cure by inducing viral antigen expression and augmenting infected cell killing. Programmed death-1 (PD-1) blockade is a potential means to both activate and eliminate the latent reservoir by restoring exhausted T cell function. We assessed the therapeutic efficacy of PD-1 blockade, Toll-like receptor 7 (TLR7) activation with the agonist vesatolimod, or a combination of the two agents in chronically simian immunodeficiency virus (SIV)-infected macaques suppressed with ART for more than 2 years. Despite achieving extended anti-PD-1 antibody plasma exposure and TLR7-dependent immune activation after multiple administrations, neither individual treatment nor the combination resulted in changes to viral rebound kinetics following ART interruption or reduction in the SIV reservoir size. Our data in the context of other reports demonstrating improved viral control upon PD-1 blockade suggest that its therapeutic utility may be restricted to specific experimental conditions or treatment times during viral pathogenesis.

Are valved holding chambers (VHCs) interchangeable? An in vitro evaluation of VHC equivalence.

INTRODUCTION: The European Medicines Agency (EMA) requires that a specific valved holding chamber (VHC) is designated for use with a given pressurised metered dose inhaler (pMDI). No other regulatory authorities impose similar requirements, implying that VHCs are interchangeable. This in vitro study, employing EMA assessment criteria, assessed the equivalence of four anti-static VHCs (aVHCs) versus the non-conducting VHC most widely referenced in pMDI monographs, the AeroChamber Plus™ (AC+) VHC. MATERIAL & METHODS: The "reference" AC + VHC was prepared by soaking in detergent solution. The four test aVHCs (AeroChamber Plus™ Flow-Vu™ [AC + FV]; Compact Space Chamber Plus [CSC+]; InspiraChamber [IC]; OptiChamber Diamond™ [OCD]) were tested "out-of-packet". Twenty devices of each type were evaluated. A salbutamol pMDI was actuated into each VHC with a 2-s delay between actuation and Andersen Cascade Impactor (ACI) sampling. Drug deposition in four ACI particle size groups was assessed: Group 1, >5.8-10 µm; Group 2, >3.3-5.8 µm; Group 3, >1.1-3.3 µm; Group 4, ≤1.1 µm. Equivalence versus the reference VHC was demonstrated where the 90% confidence interval for the test/reference mass ratio was within 85-118%. RESULTS: The mass retained within the VHC was similar for the AC + VHC and AC + FV aVHC, but was approximately twice as great for the other aVHCs. Salbutamol deposition in all ACI groups with the AC + FV aVHC was equivalent to the reference AC + VHC. By contrast, deposition in ACI groups 1 to 3 with the CSC+, IC and OCD aVHCs was inequivalent to (approximately half that of) the reference VHC. Inter-device variability for each VHC type was greatest for the IC and least for the AC + VHC and AC + FV aVHC. CONCLUSIONS: The performance of VHCs that superficially resemble one another may differ markedly. Thus, as implied by EMA guidelines, VHCs should not automatically be considered to be interchangeable.

Development and Evaluation of a Family of Human Face and Upper Airway Models for the Laboratory Testing of Orally Inhaled Products.

Many orally inhaled products are supplied with a facemask instead of a mouthpiece, enabling aerosolized medication to be transferred from the inhaler to the lungs when the user lacks the capability to use a mouthpiece. Until recently, laboratory evaluation of an orally inhaled product-facemask was frequently undertaken by removing the facemask, treating the facemask adapter as being equivalent to a mouthpiece. Measurements of delivered drug mass were therefore subject to bias arising from the absence of dead volume, had the facemask been present. We have described the development of the Aerosol Delivery to an Anatomic Model (ADAM) infant, small child, and adult faces and upper airways, and their subsequent evaluation. Each model possesses physical features of appropriate size, and the soft tissues are also simulated. Rudimentary underlying bony structure is also present, because its purpose is only to provide support, enabling the mechanical response of the facial soft tissues when a facemask is applied to be realized. A realistic upper airway (nasopharynx for the infant model, naso- and oropharynx for the child and oropharynx for the adult models) is also incorporated, so that each model can be used to determine the mass of inhaled medication likely to penetrate as far as the lungs where therapy is intended to be applied. Measurements of the mass of pressurized metered-dose inhaler-delivered salbutamol at a filter distal to the upper airway of each model, simulating age-appropriate tidal breathing, were remarkably consistent, almost all being in the range 0.3 to 1.0 µg/kg across the model age ranges, when expressed as a fraction of body weight.

Clinically Relevant In Vitro Testing of Orally Inhaled Products-Bridging the Gap Between the Lab and the Patient.

Current pharmacopeial methods for in vitro orally inhaled product (OIP) performance testing were developed primarily to support requirements for drug product registration and quality control. In addition, separate clinical studies are undertaken in order to quantify safety and efficacy in the hands of the patient. However, both laboratory and clinical studies are time-consuming and expensive and generally do not investigate either the effects of misuse or the severity of the respiratory disease being treated. The following modifications to laboratory evaluation methodologies can be incorporated without difficulty to provide a better linkage from in vitro testing to clinical reality: (1) examine all types of OIP with patient-representative breathing profiles which represent normal inhaler operation in accordance with the instructions for use (IFU); (2) evaluate OIP misuse, prioritizing the importance of such testing on the basis of (a) probability of occurrence and (b) consequential impact in terms of drug delivery in accordance with the label claim; and (3) use age-appropriate patient-simulated face and upper airway models for the evaluation of OIPs with a facemask. Although it is not necessarily foreseen that these suggestions would form part of future routine quality control testing of inhalers, they should provide a closer approximation to the clinical setting and therefore be useful in the preparation for in vivo studies and in improving guidance for correct use.

Are the Reference Values for the Provocative Concentration of Methacholine Appropriate for Children?

Background: Preliminary data in a randomly selected pediatric cohort study in 8-year-olds suggested a rate of positivity to a methacholine challenge test that was unexpectedly high, roughly 30%. The current recommendation for a negative methacholine test is a 20% decrease in the forced expiratory volume in one second at a dose greater than 400 µg. This was derived from studies in adults using the obsolete English Wright nebulizer. One explanation for the high incidence of positivity in the study in 8-year-olds could be that children deposit more methacholine on a µg/kg basis than adults, due to differences in their breathing patterns. The purpose of this study was to determine if pediatric breathing patterns could result in a higher dose of methacholine depositing in the lungs of children based on µg/kg body weight compared with adults. Methods: An AeroEclipse Breath Actuated nebulizer delivered methacholine aerosol, generated from a 16 mg/mL solution, for one minute, using age-appropriate breathing patterns for a 70 kg adult and a 30 and 50 kg child produced by a breathing simulator. Predicted lung deposition was calculated from the collected dose of methacholine on a filter placed at the nebulizer outport, multiplied by the fraction of the aerosol mass contained in particles ≤5 µm. The dose of methacholine on the inspiratory filter was assayed by high performance liquid chromatography (HPLC). Particle size was measured using laser diffraction technology. Results: The mean (95% confidence intervals) predicted pulmonary dose of methacholine was 46.1 (45.4, 46.8), 48.6 (45.3, 51.9), and 36.1 (34.2, 37.9) µg/kg body weight for the 30 kg child, 50 kg child, and 70 kg adult, respectively. Conclusions: On a µg/kg body weight, the predicted pulmonary dose of methacholine was greater with the pediatric breathing patterns than with the adult pattern.

Interchanging Reusable and Disposable Nebulizers Used with Home-Based Compressors May Result in Inconsistent Dosing: A Laboratory Investigation with Device Combinations Supplied to the US Healthcare Environment.

INTRODUCTION: Reusable nebulizer-compressor combinations deliver inhaled medications for patients with chronic lung diseases. On hospital discharge, the patient may take home the disposable nebulizer that was packaged and combine it with their home compressor. Though this practice may reduce waste, it can increase variability in medication delivery. Our study compared several reusable and disposable nebulizers packaged with compressor kits used in the US. We included a common disposable hospital nebulizer that may not be supplied with popular home kits but may be brought home after a hospitalization or emergency department visit. We focused on fine droplet mass < 4.7 µm aerodynamic diameter (FDM<4.7 µm), associated with medication delivery to the airways of the lungs. METHODS: We evaluated the following nebulizer-compressor combinations (n = 5 replicates): 1. OMBRA® Table Top Compressor with MC 300® reusable and Airlife™ MistyMax™ 10® disposable nebulizer, 2. Sami-the-Seal® compressor with SideStream® reusable and disposable nebulizers and Airlife™ MistyMax 10™ disposable nebulizer, 3. VIOS® compressor with LC Sprint® reusable, and VixOne® and Airlife™ MistyMax™ disposable nebulizers, 4. Innospire® Elegance® compressor with SideStream® reusable and disposable nebulizers and Airlife™ MistyMax 10™ disposable nebulizer, 5. Willis-the-Whale® compressor with SideStream® reusable and disposable nebulizers and Airlife™ MistyMax 10™ disposable nebulizer, 6. Pari PRONEB® Max compressor with LC Sprint® reusable and Airlife™ MistyMax 10™ disposable nebulizer. We placed a 3-ml albuterol solution (0.833 mg/ml) in each nebulizer. A bacterial/viral filter was attached to the nebulizer mouthpiece to capture emitted medication, with the filter exit coupled to a simulator of a tidal breathing adult (rate = 10 cycles/min; Vt = 600 ml; I/E ratio = 1:2). The filter was replaced at 1-min intervals until onset of sputter. Droplet size distributions (n = 5 replicates/system) were determined in parallel by laser diffractometry. RESULTS: Cumulative FDM<4.7 µm varied from 381 ± 33 µg for the best performing combination (Proneb/LC-Sprint) to 150 ± 21 µg for the system with the lowest output (VIOS®/MistyMax 10™). CONCLUSIONS: Substituting one nebulizer for another can result in large differences in medication delivery to the lungs.

A novel, versatile valved holding chamber for delivering inhaled medications to neonates and small children: laboratory simulation of delivery options.

BACKGROUND: Delivery of bronchodilator to infants and small children from a pressurized metered-dose inhaler with valved holding chamber (pMDI-VHC) is limited by airway narrowness, short respiratory cycle time, and small tidal volume (V(T)). There is a need for a versatile, efficient VHC, given the variety of treatment modalities. METHODS: We tested the AeroChamber Mini VHC (the internal geometry of which is optimized for aerosol delivery, and which accepts a pMDI canister that has a dose counter) in experiments to determine differences in the delivery of hydrofluoroalkane-propelled albuterol (90 microg/actuation) during: mechanical ventilation via endotracheal tube (ETT); manual resuscitation via ETT; and spontaneous breathing via face mask. We tested 5 units of the AeroChamber Mini VHC per test. We simulated the tidal breathing of a premature neonate (V(T) 6 mL), a term neonate (V(T) 20 mL), and a child approximately 2 years old (V(T) 60 mL). We collected the aerosol on an electret filter and quantitatively assayed for albuterol. RESULTS: The total emitted mass of albuterol per actuation that exited the VHC was marginally greater during spontaneous breathing (12.1 +/- 1.8 microg) than during manual resuscitation (10.0 +/- 1.1 microg) (P = .046). Albuterol delivery via mechanical ventilation, though comparable with the premature-neonate model (3.3 +/- 1.2 microg), the term-neonate model (3.8 +/- 2.1 microg), and the 2-y-old-child model (4.2 +/- 2.3 microg) (P = .63), was significantly lower than in the spontaneous-breathing and manual-resuscitation models (P < .001). In the neonatal models the total emitted mass was similar with the spontaneous-breathing model (6.0 +/- 1.0 microg with the premature-neonate model, 10.5 +/- 0.7 microg with the term-neonate model) and the manual-resuscitation model (5.5 +/- 0.3 microg premature-neonate model, 10.7 +/- 0.9 microg term-neonate model) (P > or = .46 via one-way analysis of variance). CONCLUSION: The reduced delivery of albuterol during mechanical ventilation (compared to during spontaneous breathing and manual resuscitation via ETT) was probably associated with the saturated atmosphere in the breathing circuit (37 degrees C, relative humidity > 99%), compared to the ambient air (22 +/- 1 degrees C, 44 +/- 7% relative humidity). The AeroChamber Mini VHC may provide a versatile alternative to VHCs that are designed exclusively for one aerosol treatment modality.

Relative precision of inhaler aerodynamic particle size distribution (APSD) metrics by full resolution and abbreviated andersen cascade impactors (ACIs): part 1.

The purpose of this study was to compare relative precision of two different abbreviated impactor measurement (AIM) systems and a traditional multi-stage cascade impactor (CI). The experimental design was chosen to provide separate estimates of variability for each impactor type. Full-resolution CIs are useful for characterizing the aerosol aerodynamic particle size distribution of orally inhaled products during development but are too cumbersome, time-consuming, and resource-intensive for other applications, such as routine quality control (QC). This article presents a proof-of-concept experiment, where two AIM systems configured to provide metrics pertinent to QC (QC-system) and human respiratory tract (HRT-system) were evaluated using a hydrofluoroalkane-albuterol pressurized metered dose inhaler. The Andersen eight-stage CI (ACI) served as the benchmark apparatus. The statistical design allowed estimation of precision with each CI configuration. Apart from one source of systematic error affecting extra-fine particle fraction from the HRT-system, no other bias was detected with either abbreviated system. The observed bias was shown to be caused by particle bounce following the displacement of surfactant by the shear force of the airflow diverging above the collection plate of the second impaction stage. A procedure was subsequently developed that eliminated this source of error, as described in the second article of this series (submitted to AAPS PharmSciTech). Measurements obtained with both abbreviated impactors were very similar in precision to the ACI for all measures of in vitro performance evaluated. Such abbreviated impactors can therefore be substituted for the ACI in certain situations, such as inhaler QC or add-on device testing.

Relative precision of inhaler aerodynamic particle size distribution (APSD) metrics by full resolution and abbreviated andersen cascade impactors (ACIs): part 2--investigation of bias in extra-fine mass fraction with AIM-HRT impactor.

The purpose of this study was to resolve an anomalously high measure of extra-fine particle fraction (EPF) determined by the abbreviated cascade impactor possibly relevant for human respiratory tract (AIM-HRT) in the experiment described in Part 1 of this two-part series, in which the relative precision of abbreviated impactors was evaluated in comparison with a full resolution Andersen eight-stage cascade impactor (ACI). Evidence that the surface coating used to mitigate particle bounce was laterally displaced by the flow emerging from the jets of the lower stage was apparent upon microscopic examination of the associated collection plate of the AIM-HRT impactor whose cut point size defines EPF. A filter soaked in surfactant was floated on top of this collection plate, and further measurements were made using the same pressurized metered-dose inhaler-based formulation and following the same procedure as in Part 1. Measures of EPF, fine particle, and coarse particle fractions were comparable with those obtained with the ACI, indicating that the cause of the bias had been identified and removed. When working with abbreviated impactors, this precaution is advised whenever there is evidence that surface coating displacement has occurred, a task that can be readily accomplished by microscopic inspection of all collection plates after allowing the impactor to sample ambient air for a few minutes.

In vitro and clinical characterization of the valved holding chamber AeroChamber Plus® Flow-Vu® for administrating tiotropium Respimat® in 1-5-year-old children with persistent asthmatic symptoms.

BACKGROUND: When characterizing inhalation products, a comprehensive assessment including in vitro, pharmacokinetic (PK), and clinical data is required. We conducted a characterization of tiotropium Respimat® when administered with AeroChamber Plus® Flow-Vu® anti-static valved holding chamber (test VHC) with face mask in 1-5-year-olds with persistent asthmatic symptoms. METHODS: In vitro tiotropium dose and particle size distribution delivered into a cascade impactor were evaluated under fixed paediatric and adult flow rates between actuation and samplings. The tiotropium mass likely to reach children's lungs was assessed by tidal breathing simulations and an ADAM-III Child Model. PK exposure to tiotropium in preschool children with persistent asthmatic symptoms (using test VHC) was compared with pooled data from nine Phase 2/3 trials in older children, adolescents, and adults with symptomatic persistent asthma not using test VHC. RESULTS: At fixed inspiratory flow rates, emitted mass and fine particle dose decreased under lower flow conditions; dose reduction was observed when Respimat® was administered by test VHC at paediatric flow rates. In <5-year-old children, such a dose reduction is appropriate. In terms of dose per kg/body weight, in vitro-delivered dosing in children was comparable with adults. Transmission and aerosol holding properties of Respimat® when administered with test VHC were fully sufficient for aerosol delivery to patients. At zero delay, particles <5 µm (most relevant fraction) exhibited a transfer efficacy of ≥60%. The half-time was>10 s, allowing multiple breaths. Standardized tidal inhalation resulted in an emitted mass from the test VHC of approximately one-third of labelled dose, independent of coordination and face mask use, indicating predictable tiotropium administration by test VHC with Respimat®. Tiotropium exposure in 1-5-year-old patients using the test VHC, when adjusted by height or body surface, was comparable with that in older age groups without VHCs; no overexposure was observed. Adverse events were less frequent with tiotropium (2.5 µg, n = 20 [55.6%]; 5 µg, n = 18 [58.1%]) than placebo (n = 25 [73.5%]). CONCLUSIONS: Our findings provide good initial evidence to suggest that tiotropium Respimat® may be administered with AeroChamber Plus® Flow-Vu® VHC in 1-5-year-old patients with persistent asthmatic symptoms. To confirm the clinical efficacy and safety in these patients, additional trials are required. CLINICAL TRIALS REGISTRY NUMBER: The trial was registered under NCT01634113 at http://www.clinicaltrials.gov.

Electrostatics and inhaled medications: influence on delivery via pressurized metered-dose inhalers and add-on devices.

The movement of inhaler-generated aerosols is significantly influenced by electrostatic charge on the particles and on adjacent surfaces. Particle charging arises in the aerosol formation process. Since almost all inhalers contain nonconducting components, these surfaces can also acquire charge during manufacture and use. Spacers and valved holding chambers used with pressurized metered-dose inhalers to treat obstructive lung diseases are particularly prone to this behavior, which increases variability in the amount of medication available for inhalation, and this is exacerbated by low ambient humidity. This may result in inconsistent medication delivery. Conditioning the device by washing it with a conductive surfactant (detergent) or using devices made of charge-dissipative/conducting materials can mitigate electrostatic charge. This review discusses sources of electrostatic charge, the processes that influence aerosol behavior, methods to mitigate electrostatic charge, and potential clinical implications.

Levalbuterol aerosol delivery with a nonelectrostatic versus a nonconducting valved holding chamber.

BACKGROUND: Hydrofluoroalkane-propelled levalbuterol (Xopenex) aerosol is a recently approved formulation for delivery via metered-dose inhaler for the treatment or prevention of bronchospasm in adults, adolescents, and children > or = 4 years of age who have reversible obstructive airway disease. Valved holding chambers (VHCs) made from conventional polymers are susceptible to accumulation of electrostatic charge, which can be minimized by prewashing with ionic detergent, but it may be desirable to be able to use the product straight from the package, without pretreatment, especially during an exacerbation. METHODS: We studied the performance of the AeroChamber Plus and AeroChamber Max VHCs in delivering hydrofluoroalkane-propelled levalbuterol. Both VHCs were prewashed, rinsed, and drip-dried before testing. The AeroChamber Max is manufactured from charge-dissipative material and was therefore also evaluated without prewashing. Aerosol samples were collected at 28.3 L/min with an Andersen 8-stage cascade impactor, per the procedure specified in Chapter 601 of the United States Pharmacopeia. RESULTS: The mean +/- SD fine-particle mass (mass of aerosol particles < 4.7 microm aerodynamic diameter) values were 33.5 +/- 1.4 microg and 36.3 +/- 1.1 microg with the AeroChamber Max, without and with wash/rinse pretreatment, respectively, and 28.5 +/- 2.4 microg with the prewashed AeroChamber Plus. CONCLUSIONS: We think the small differences we observed are unlikely to be of clinical importance, given the inter-patient variability seen with inhaled drug delivery. The performance of the AeroChamber Max was substantially comparable whether or not it was prewashed.

The importance of nonelectrostatic materials in holding chambers for delivery of hydrofluoroalkane albuterol.

INTRODUCTION: Electrostatic attraction of aerosolized particles to the inner walls of an aerosol holding chamber (HC) made from a nonconducting material can reduce medication delivery, particularly if there is a delay between actuation and inhalation. OBJECTIVE: Compare total emitted mass and fine-particle mass (mass of particles < 4.7 microm) of hydrofluoroalkane-propelled albuterol from similar-sized HCs manufactured from conductive material (Vortex), charge-dissipative material (AeroChamber Max), and nonconductive material (OptiChamber Advantage, ProChamber, Breathrite, PocketChamber, and ACE), with and without wash/rinse pretreatment of the HC interior with ionic detergent, and with 2-s and 5-s delays between actuation and inhalation. METHODS: All the HCs were evaluated (1) directly from their packaging (with no wash/rinse pretreatment) and (2) after washing with ionic detergent and rinsing and drip-drying. We used an apparatus that interfaced between the HC mouthpiece and the induction port of an 8-stage Andersen cascade impactor to simulate a poorly coordinated patient, with delays of 2 s and 5 s between actuation and inhalation/sampling, at 28.3 L/min. RESULTS: With the 2-s delay, the delivered fine-particle mass per actuation, before and after (respectively) wash/rinse pretreatment was: AeroChamber Max: 23.8 +/- 4.8 microg, 21.5 +/- 3.2 microg; Vortex: 16.2 +/- 1.7 microg, 15.5 +/- 2.0 microg; OptiChamber Advantage: 2.6 +/- 1.2 microg, 6.7 +/- 2.3 microg; ProChamber: 1.6 +/- 0.4 microg, 5.1 +/- 2.5 microg; Breathrite: 2.0 +/- 0.9 microg, 3.2 +/- 1.8 microg; PocketChamber: 3.4 +/- 1.6 microg, 1.7 +/- 1.6 microg; ACE: 4.5 +/- 0.9 microg, 5.4 +/- 2.9 microg. Similar trends, but greater reduction in aerosol delivery, were observed with the 5-s delay. Significantly greater fine-particle mass was delivered from HCs made from conducting or charge-dissipative materials than from those made from nonconductive polymers, even after wash/rinse pretreatment (p < 0.01). The fine-particle mass was also significantly greater from the AeroChamber Max than from the Vortex, irrespective of wash/rinse pretreatment or delay interval (p < 0.01). CONCLUSION: HCs made from electrically conductive materials emit significantly greater fine-particle mass, with either a 2-s or 5-s delay, than do HCs made from nonconducting materials, even with wash/rinse pretreatment.

Laser diffractometry as a technique for the rapid assessment of aerosol particle size from inhalers.

The rapid assessment of aerosols produced by medicinal inhalers is highly desirable from several standpoints, including the assurance of product quality, the development of new delivery systems, and the need to meet an increasing requirement by regulatory bodies for reliable in vitro performance data. Particle size analysis has traditionally been undertaken by cascade impactor on account of the direct assessment of active pharmaceutical ingredient(s) (APIs) that is possible by this method. However, laser diffractometry is less labor-intensive, more rapid, and can be a less invasive procedure. The technique provides meaningful results; as long as precautions are taken to validate that the measurements are an accurate reflection of the distribution of API mass as a function of particle or droplet size. We begin the review by examining the underlying theory of the laser diffraction method. After a brief description of current laser diffractometers used in inhaler measurements, we continue by examining the range of applications by inhaler class. We then examine the basis upon which inhaler measurements made by laser-diffractometry can be compared with equivalent particle size distribution data from compendial techniques. We conclude the assessment of the technique by developing guidelines for its valid application as a component of the range of in vitro methods that are available for inhaler performance assessment.

Comparison of three valved holding chambers for the delivery of fluticasone propionate-HFA to an infant face model.

The purpose of this study was to compare three valved holding chambers (VHC) with facemasks attached. One VHC (AeroChamber Max[TM] with medium mask) was made with materials that dissipate surface electrostatic charge, and the others (OptiChamber Advantage and ProChamber[TM] with pediatric facemask) were made from non-conducting materials. The OptiChamber Advantage and ProChamber VHCs were each washed with an ionic detergent and drip dried before testing to minimize surface electrostatic charge. The AeroChamber Max VHCs were tested "out of the package" and also after wash, rinse, and drying. An infant face model incorporating an electrostatic filter in the oral cavity was connected to a breath simulator using a standard waveform for a small child. The fit of each VHC with facemask was demonstrated by agreement of inspiratory flow measurements between a pneumotachograph connected to the system with those set on the simulator. An HFA-fluticasone propionate metered dose inhaler (MDI; 125 microg/dose) was inserted into the VHC, two actuations were delivered, and the filters were subsequently assayed using high-pressure liquid chromatography (HPLC). Testing and sample assay order was randomized, and HPLC assays were undertaken blinded. Drug delivery efficiency expressed as a percentage of the total dose of fluticasone propionate (250 microg) for the AeroChamber Max VHC "out-of-the-package" was 22.0(0.7)% (mean [99% CI]) and 21.2(1.5)% when pre-washed/rinsed. Results for the pre-washed ProChamber and OptiChamber Advantage VHCs were 10.2(0.55)% and 8.8(1.9)%, respectively. The more efficient delivery of medication via VHCs made from electrostatic charge dissipative materials should be considered when choosing doses for small children.

Application of heated inlet extensions to the TSI 3306/3321 system: comparison with the Andersen cascade impactor and next generation impactor.

Pharmaceutical aerosol size distribution analysis based on multi-stage inertial impaction is well accepted, though laborious. The TSI 3306 Impactor Inlet/3321 time-of-flight (TOF) Aerodynamic Particle Size Analyzer (APS) has been evaluated for its ease of use and potential for time savings during product development. However, instrument inlet modifications may be necessary for increased correlation with equivalent measurements obtained by inertial impaction following pharmacopeial methods. A heated inlet extension tube was located between the USP/Ph.Eur. throat and the Single-Stage Impactor (SSI) to promote evaporation of residual ethanol from aerosol droplets, generated from two formulations containing ethanol as semi-volatile solubilizer (8 and 20% w/w) for the active pharmaceutical ingredient. As temperature and extension length increased, the SSI-measured fine particle fraction (aerosol < 4.7 microm aerodynamic diameter) also increased, for the aerosols used in this study. These values correlated quite closely with equivalent measures made by multi-stage cascade impactor equipped with the same throat. Particle size distribution profiles measured with the APS for either formulation did not significantly change utilizing the heated extensions, suggesting that ethanol evaporation was largely complete at any condition by the time the aerosol entered the measurement zone of the TOF analyzer. The addition of a heated inlet extension may be useful to facilitate evaporation of residual semi-volatile species, especially when an agreement of APS-derived particle size mass distribution data from the SSI with multi-stage cascade impactors is desired. However, complete evaporation of the semi-volatile species may not be necessary for SSI-generated mass distribution to match conventionally used cascade impactors.

The Effect of Body Mass on Eccentric Knee-Flexor Strength Assessed With an Instrumented Nordic Hamstring Device (Nordbord) in Football Players.

PURPOSE: To examine the effect of body mass (BM) on eccentric knee-flexor strength using the Nordbord and offer simple guidelines to control for the effect of BM on knee-flexor strength. METHODS: Data from 81 soccer players (U17, U19, U21, senior 4th French division, and professionals) and 41 Australian Football League (AFL) players were used for analysis. They all performed 1 set of 3 maximal repetitions of the bilateral Nordic hamstring exercise, with the greatest strength measure used for analysis. The main regression equation obtained from the overall sample was used to predict eccentric knee-flexor strength from a given BM (moderate TEE, 22%). Individual deviations from the BM-predicted score were used as a BM-free index of eccentric knee- flexor strength. RESULTS: There was a large (r = .55, 90% confidence limits .42;.64) correlation between eccentric knee-flexor strength and BM. Heavier and older players (professionals, 4th French division, and AFL) outperformed their lighter and younger (U17-U21) counterparts, with the soccer professionals presenting the highest absolute strength. Professional soccer players were the only ones to show strength values likely slightly greater than those expected for their BM. CONCLUSIONS: Eccentric knee-flexor strength, as assessed with the Nordbord, is largely BM-dependent. To control for this effect, practitioners may compare actual test performances with the expected strength for a given BM, using the following predictive equation: Eccentric strength (N) = 4 × BM (kg) + 26.1. Professional soccer players with specific knee-flexor-training history and enhanced neuromuscular performance may show higher than expected values.