Related Articles

The Influence of Initial Atomized Droplet Size on Residual Particle Size from Pressurized Metered Dose Inhalers.

Int J Pharm. 2013 Aug 1;

Authors: Sheth P, Stein SW, Myrdal PB

Abstract
Pressurized metered dose inhalers (pMDIs) are widely used for the treatment of diseases of the lung, including asthma and chronic obstructive pulmonary disease. The mass median aerodynamic diameter of the residual particles (MMADR) delivered from a pMDI plays a key role in determining the amount and location of drug deposition in the lung and thereby the efficacy of the inhaler. The mass median diameter of the initial droplets (MMDI), upon atomization of a formulation, is a significant factor influencing the final particle size. The purpose of this study was to evaluate the extent that MMDI and initial droplet geometric standard deviation (GSD) influence the residual aerodynamic particle size distribution (APSDR) of solution and suspension formulations. From 48 solution pMDI configurations with varying ethanol concentrations, valve sizes and actuator orifice diameters, it was experimentally found that the effective MMDI ranged from 7.8 to 13.3μm. Subsequently, computational methods were utilized to determine the influence of MMDI on MMADR, by modulating the MMDI for solution and suspension pMDIs. For solution HFA-134a formulations of 0.5% drug in 10% ethanol, varying the MMDI from 7.5 to 13.5μm increased the MMADR from 1.4 to 2.5μm. For a suspension formulation with a representative particle size distribution of micronized drug (MMAD = 2.5μm, GSD = 1.8), the same increase in MMDI resulted in an increase in the MMADR from 2.7 to only 3.3μm. Hence, the same increase in MMDI resulted in a 79% increase in MMADR for the solution formulation compared to only a 22% increase for the suspension formulation. Similar trends were obtained for a range of drug concentrations and input micronized drug sizes. Thus, APSDR is more sensitive to changes in MMDI for solution formulations than suspension formulations; however, there are situations in which hypothetically small micronized drug in suspension (e.g. 500nm MMAD) could resemble trends observed for solution formulations. Furthermore, the relationship between APSDR and drug concentration and MMDI is predictable for solution pMDIs, but this is not as straightforward for suspension formulations. In addition, the MMADR was relatively insensitive to changes in initial droplet GSD (from 1.6 to 2.0) and the solution and suspension pMDI residual particle GSDs were essentially identical to the initial droplet GSDs.

PMID: 23911912 [PubMed - as supplied by publisher]

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Summary of the British Thoracic Society guideline for diagnostic flexible bronchoscopy in adults.

Thorax. 2013 Aug;68(8):786-7

Authors: Du Rand IA, Blaikley J, Booton R, Chaudhuri N, Gupta V, Khalid S, Mandal S, Martin J, Mills J, Navani N, Rahman NM, Wrightson JM, Munavvar M, British Thoracic Society Bronchoscopy Guideline Group

Abstract
Flexible bronchoscopy is an essential, established and expanding tool in respiratory medicine. Its practice, however, needs to be safe, effective and for the right indications to maximise clinical utility. This guideline is based on the best available evidence and is a revised update of the British Thoracic Society guideline on diagnostic flexible bronchoscopy.

PMID: 23842821 [PubMed - in process]

Health promotion board-ministry of health clinical practice guidelines: treating tobacco use and dependence.

Singapore Med J. 2013 Jul;54(7):411-6

Authors: Chan K, Chandler J, Cheong K, Giam PE, Kanagalingam D, Lee LL, Leong LL, Ng Y, Oh C, Shi M, Tan AS, Tan CM, Tan TL, Utravathy V

Abstract
The Health Promotion Board (HPB) has updated the clinical practice guidelines on Treating Tobacco Use and Dependence to provide health professionals in Singapore with evidence-based interventions for smoking cessation. This article reproduces the introduction and executive summary of key guideline recommendations (with recommendations from the guidelines) from the HPB-MOH Clinical Practice Guidelines on Treating Tobacco Use and Dependence, for the information of SMJ readers. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Health Promotion Board website: http://www.hpb.gov.sg/cpg-smoking-cessation. The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

PMID: 23900473 [PubMed - in process]

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Ultrasound-Assisted Thrombolysis in Submassive and Massive Pulmonary Embolism: Assessment of Lung Obstruction Before and After Catheter-Directed Therapy.

Cardiovasc Intervent Radiol. 2013 Jul 17;

Authors: Quintana D, Salsamendi J, Fourzali R, Narayanan G

Abstract
PURPOSE: New treatment guidelines support the use of catheter-directed therapy for both massive and submassive pulmonary embolism (PE). This study examines the safety and effectiveness of ultrasound-accelerated (UA) thrombolysis, for which prompt treatment is warranted to rapidly resolve thrombus and restore cardiopulmonary function.
MATERIALS AND METHODS: We retrospectively reviewed ten consecutive, acute submassive/massive PE patients. All patients exhibited acute symptoms and computed tomography evidence of large thrombus burden and evidence of right-ventricular (RV) dysfunction and/or failure. Patients were followed-up with posttreatment echocardiography (n = 7) and CT (n = 9) to evaluate right heart dysfunction and thrombus burden, respectively. Thrombolytic treatment was performed in all patients using the EkoSonic Endovascular system. Clinical outcomes and complications, RV pressures, and thrombus removal were evaluated. Paired Wilcoxon signed-rank tests were performed to analyze the pretreatment and posttreatment measures; p < 0.05 was considered significant.
RESULTS: Median thrombolytic dose was 18.0 mg tissue plasminogen activator infused over 20.8 h. There was a significant decrease in pretreatment and posttreatment RV pressures (52.0-30.0; p < 0.01); there was a significant decrease in pretreatment and posttreatment Mastora obstructive indices (74-43; p < 0.01). All patients improved clinically shortly after treatment onset. All ten patients survived to discharge with a median intensive care (ICU) stay of 4 days and 14 hospital days.
CONCLUSION: UA thrombolysis is promising in massive and submassive PE treatment and shows safe results. Patients showed improved thrombus burden, and rapid improvement in right cardiac function, whereas minimizing bleeding risk and ICU time were minimized. This results of this study provide the foundation for future comparative studies in treatment of large PEs.

PMID: 23860937 [PubMed - as supplied by publisher]