Scintigraphic assessment of the oropharyngeal and nasal depositions of fusafungine from a pressurized inhaler and from a novel pump spray device

Evaluation of Nasal Inlet Ports Having Simplified Geometry for the Pharmacopeial Assessment of Mass Fraction of Dose Likely to Penetrate Beyond the Nasopharynx: a Preliminary Investigation

Nasal cavity breakthrough to the airways of the lungs is associated with nasally inhaled droplets whose size is smaller than ca. 10 μm aerodynamic diameter that behave as an aerosol rather than a spray in terms of their transport. The purpose of the present laboratory-based study was to evaluate a nasal product quality control procedure involving a new inlet for the quantification of mass of such droplets emitted by commercially available aqueous nasal spray pump products by cascade impactor. This inlet is more representative of the adult nasal vestibule in terms of entry angle for the spray as well as internal volume for plume expansion. Sampling was also undertaken via a spherical 1-L glass expansion vessel as inlet, previously established for quantification of these aerosol droplets. The selected solution- and suspension-formulated products containing azelastine and fluticasone propionate respectively were shown to contain < 1% of the total spray mass per actuation associated with droplets < 14.1 μm aerodynamic diameter. These measurements were consistent with laser diffraction-based measurements of the entire droplet size distribution. Comparable measures of aerosol droplet mass fraction were obtained when the spray was sampled by the cascade impactor method using either the 1-L glass expansion chamber or the new metal inlet as entry for the spray produced by either product evaluated. We conclude that the metal inlet has the potential to be adopted as a suitable induction port in the assessment of nasal product quality, where currently no standardized inlet exists.

A computational fluid dynamics model for drug delivery in a nasal cavity with inferior turbinate hypertrophy

BACKGROUND

Intranasal medications are commonly used in treating nasal diseases. However, technical details of the correct usage of these medications for nasal cavity with obstruction are unclear.

METHODS

A three-dimensional model of nasal cavity was constructed from MRI scans of a healthy human subject. Nasal cavities corresponding to healthy, moderate, and severe nasal obstruction (NO) were simulated by enlarging the inferior turbinate geometrically, which was documented by approximately one-third reduction of the minimum cross-sectional area for the moderate and two-thirds for the severe obstruction. The discrete phase model based on steady-state computational fluid dynamics was used to study the gas-particle flow. The results were presented with drug particle (from 7 x 10⁻⁵ to 10⁻⁷ m) deposition distribution along the lateral walls inside these three nasal cavities, and comparisons of the particle ratio escaping from the cavity were also presented and discussed.

RESULTS

Nasal patency is an essential condition that had the most impact on particle deposition of the factors studied; the particle percentage escaping the nasal cavity decreased to less than a half and one-tenth for the moderately and severely blocked noses. Decreasing of flow rate and particle diameter increased the escaping ratio; however, zero escaping percentage was detected with the absence of air flow and the effect was less noticeable when the particle diameter was very small (<10⁻⁶ m). The existence of inspiratory flow and head tilt angle helped to improve the particle escaping ratio for the healthy nose; however, such changes were not significant for the moderately and severely blocked noses.

CONCLUSION

When using an intranasal medication, it is advisable to have a moderate inspiratory air-flow rate and small size particles to improve particle escaping ratio. Various head positions suggested by clinicians do not seem to improve the drug escaping ratio significantly for the nasal cavities with inferior turbinate hypertrophy.

Numerical simulations investigating the regional and overall deposition efficiency of the human nasal cavity

Numerical simulations have been carried out on a model of the right passageway of an anonymous, adult male's nasal cavity, constructed from magnetic resonance imagery (MRI) scans. Steady, laminar, inspiratory flow was assumed to simulate inhalation. Analysis shows smoothly varying streamlines with a peak in velocity magnitude occurring in the nasal valves and a peak in vorticity magnitude immediately posterior. Dilute, uniform concentrations of inertial (1 microm < or = d(ae) < or = 10 microm) particles were released at the nostril and tracked via a Lagrangian tracking algorithm. Deposition efficiency is shown to increase with particle size and flow rate. Preferential deposition is seen in the anterior third of the nasal cavity for large Stokes number particles. An empirical expression for particle deposition is proposed that incorporates particle size, flow rate, and nose anatomy.

Distribution and clearance of bioadhesive formulations from the olfactory region in man: Effect of polymer type and nasal delivery device

There is an increasing need to identify novel approaches by which to improve the efficiency of drug transport from the nasal cavity (olfactory region) to the CNS, especially for treatment of central nervous system disorders. It is suggested, that one approach is the combination of active targeting of a bioadhesive formulation, that will retain the drug at the absorption site, potentially in combination with, an absorption enhancer. Two low methylated pectins, LM-5 and LM-12 were selected for evaluation as drug delivery systems, due to their ability to gel in the nasal cavity and their bioadhesive characteristics, together with chitosan G210, which acts both as a bioadhesive material and as an efficient absorption enhancer. It was found that all of the bioadhesive formulations were able to reach the olfactory region in the nasal cavity of human volunteers when delivered using a simple nasal drop device. Furthermore, the formulations displayed a significantly increased residence time on the epithelial surface. This was in contrast to a non-bioadhesive control delivered with the same device. In contrast, a pectin formulation administered with a nasal spray system did not show an increase in residence time in the olfactory region. It was further shown that the reproducibility of olfactory delivery of a polymer formulation was significantly better intra-subject than inter-subject.

The effect of scatter and attenuation on aerosol deposition as determined by gamma scintigraphy

Gamma scintigraphy is often used to quantify deposition patterns from aerosol inhalers. The errors caused by scatter and tissue attenuation in planar Tc-99m gamma scintigraphy were investigated based on the data collected from four subjects in this study. Several error correction methods were tested. The results from two scatter correction methods, Jaszczak's method and factor analysis of dynamic sequences (FADS), were similar. Scatter accounted for 20% of raw data in the whole lung, 20% in the oropharynx, and 43% in the central airways and esophagus. Three attenuation correction methods were investigated and compared. These were: uniform attenuation correction (UAC), a known method used for inhalation drug imaging work; the broad-beam attenuation correction used for organ imaging in nuclear medicine; and a narrow-beam inhomogeneous tissue attenuation correction proposed in this study. The three methods differed significantly (p < 0.05), but all indicated that attenuation is a severe quantification problem. The narrow beam attenuation correction with scatter correction, showed that raw data underestimated tracer deposition by 44% in the lung, 137% in the oropharynx, and 153% in the trachea/esophageal region. To quantify aerosol lung deposition using planar scintigraphy even in relative terms, corrections are necessary. Much of the literature concerning quantified aerosol dose distributions measured by gamma scintigraphy needs to be interpreted carefully.

Inhalation therapy: new delivery systems

The objective of this article is to provide an overview of recent advances in inhalation drug delivery. Problems, advantages, limitations, and developments encountered by different inhalation devices and the agents used in these for the purpose of pulmonary delivery are discussed. A critical appraisal is presented and finally the future directions especially in research of the inhaled therapeutics and aerosols are described.

Comparison of once daily fluticasone propionate aqueous nasal spray with once daily budesonide reservoir powder device in patients with perennial rhinitis

BACKGROUND

Previous studies comparing the corticosteroids fluticasone propionate (FP) and budesonide (BUD) in both perennial and seasonal rhinitis have shown no consistent difference between treatments. However, the therapeutic outcomes may have been influenced by study design.

OBJECTIVE

To compare the effect of FP aqueous nasal spray (ANS; 200 microg/day) with BUD reservoir powder device (RPD; 200 microg/day) on rhinitis symptoms, productivity loss and device preference in patients with perennial rhinitis.

METHODS

After a 2-week run-in period, 440 patients were randomized to receive either FPANS, BUD RPD or matched placebo (ANS or RPD) for 8 weeks, followed by an open-label 4-week follow-up treatment with FPANS. Patients completed diary card visual analogue scores for nasal symptoms, and questionnaires on satisfaction with the treatment and preferred choice of device.

RESULTS

During weeks 1-4, the visual analogue total nasal symptom scores (VATNS) in the FPANS group were significantly lower than scores in the BUD RPD group (mean difference = -17.8; 95% CI = -34.4, -1.3; P = 0.036). FPANS also significantly reduced the VATNS compared with the ANS placebo at all time-points assessed (P < or = 0.005). BUD RPD did not significantly differ from the RPD placebo at weeks 5-8 (P = 0.167), or the ANS placebo at any time-point (P < or = 0.151). Over the 8-week treatment period FPANS was significantly more effective than BUD RPD at reducing sneezing (mean difference = -4.4; 95% CI = -8.6, -0.3; P = 0.036) and nasal itching (mean difference = -5.3; 95% CI = -9.9, -0.8; P = 0.022), and was significantly superior to the ANS placebo for all symptoms assessed at weeks 1-4 and 1-8 (P < 0.016). At the same time-points BUD RPD was no better at alleviating nasal itching than the RPD placebo (P < or = 0.306), and compared with the ANS placebo, significantly reduced only one symptom; nasal blockage (P < or = 0.016). After 8 weeks of treatment, patients preferred the ANS device to the RPD (P < 0.001), and at 12 weeks a significantly greater number of patients were satisfied with FPANS treatment compared with BUD RPD (P = 0.0019) or the respective placebos (P = 0.0001).

CONCLUSION

FPANS and BUD RPD are effective therapies with a good safety profile for the treatment of perennial rhinitis but, in this direct placebo-controlled comparison, FPANS was more efficacious than BUD RPD, and the patients preferred the ANS device to the RPD.

Variability in lung deposition of inhaled drug, within and between asthmatic patients, with a pMDI and a dry powder inhaler, Turbuhaler

In vitro analysis of inhaled formulations measures, among other parameters, the variability in delivered dose, while a corresponding in vivo analysis also includes the variability caused by patient performance and distribution of drug between the oropharynx and the lungs. In vitro, the dose variability is higher for Turbuhaler(R) than for the corresponding pMDI, whereas in vivo, the converse is true: the variability in lung deposition is significantly higher, both between and within subjects, for pMDI than for Turbuhaler. The observation can be due to several factors such as the non-continuous working principle of inhalation via pMDI as opposed to the continuous working principle of inhalation via Turbuhaler.

Aspiration of nasal secretions into the lungs in patients with acute sinonasal infections

OBJECTIVES

To compare the amounts of nasal secretions aspirated into the lower airway by patients with acute sinonasal infection with that aspirated by healthy adults during sleep.

STUDY DESIGN

Sixteen patients who had received a diagnosis of acute sinonasal infections by accurate history, anterior rhinoscopic examination, and radiological assessment and 13 healthy volunteers, aged 14 to 45 years.

METHODS

A 10-mCi dose of technetium 99m-labeled macroaggregated albumin (Tc-99m MAA) with a concentration of 1 mCi/mL was prepared at midnight, just before sleep. Each subject was administered two puffs of this spray. At 8 AM the next morning transmission and emission views of the thorax were taken with a gamma camera.

RESULTS

No significant difference between the two groups was observed in the amounts of nasal secretions aspirated into the lungs.

CONCLUSIONS

The amount of nasal secretions aspirated does not increase during acute sinonasal infection. However, by irritating the mucosa of the lower respiratory tracts, bacteria, toxins, and inflammatory products existing in purulent secretions may play a major role in the pathophysiology of asthma and sinusitis.

Nasal delivery systems and their effect on deposition and absorption

Due to nasal anatomy and physiology, with a non-ciliated area in the anterior part of the nasal cavity and a ciliated region in the more posterior part of the nose, the site of deposition is of importance for the nasal mucociliary clearance and retainment of a formulation in the nose. Many drug delivery devices for nasal application of liquid, semisolid and solid formulations were investigated in respect to their deposition in the nasal cavity. The site of deposition and the deposition area depend on several parameters which are related to the delivery device, such as mode of administration, particle size of the formulation and velocity of the delivered particles. Several in vitro and in vivo methods have been used to study distribution and clearance of intranasally delivered therapeutics. The relationship between deposition, absorption and related bioavailability of the nasally applied formulation has been shown.