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Adherence and Asthma
Published in Lynn B. Myers, Kenny Midence, Adherence to Treatment in Medical Conditions, 2020
New drugs for asthma that have recently been developed include long-acting β2-agonists (salmeterol and eformoterol) and inhaled steroids that are believed to have less systemic effects (fluticasone). Inevitably newer treatments are initially more expensive, but studies are needed to test their cost-effectiveness, which may be dependant upon patient acceptability and adherence. The early signs are promising with the costs of treatment increasing but the overall costs of care decreasing (Price, 1995b). Treatments in tablet form, such as the newly developed leukotriene inhibitors, may simplify management and improve adherence. New inhaler devices, using environmentally friendly propellants, may also make taking treatment easier.
Innovations and Future Prospects of Dermal Delivery Systems
Published in Tapash K. Ghosh, Dermal Drug Delivery, 2020
Rashmi Upasani, Anushree Herwadkar, Neha Singh, Ajay K. Banga
Pharmaceutical aerosols are dynamic systems which have gained popularity as topical vehicles. These are formulations comprising of a gas dispersed in liquid phase. The basic components of the aerosol system are container, propellant, formulation concentrate, valve and actuator. The formulation is typically an emulsion containing one or more actives, surfactants, co-solvents and a propellant. Upon valve actuation, the propellant evaporates to produce foam or a spray. If the propellant is in the internal phase of the emulsion, stable foam is discharged, and if the propellant is in the external phase, a spray or quick-breaking foam is discharged. The nature of these device and formulation components determine foam/spray characteristics such as particle size distribution, dose uniformity (for metered valves), delivery rate, spray pattern, foam density, etc. The propellant plays a pivotal role in the delivery of foam/spray on to the skin. It supplies the necessary pressure within the aerosol system to expel material from the container. A variety of propellants are included in formulations, including compressed gases (carbon dioxide, nitrogen), hydrocarbons (butanes, pentanes) and hydrofluroalkanes.
Acute Lung Injury In Children Due To Chemical And Physical Agents
Published in Lourdes R. Laraya-Cuasay, Walter T. Hughes, Interstitial Lung Diseases in Children, 2019
The toxicity of propellants has been well publicized and has also been the topic of comprehensive reviews.362, 363 Shortly after the introduction of the pocket-sized aerosolized bronchodilator cannisters in 1956, the death rates due to asthma were noted to rise, and concern was voiced about the abuse and overuse of such medication.363 The first case reports of death due to pressurized aerosols appeared in 1967.364 These deaths were sudden and may have been due to many factors, including a sensitization of the myocardium by the propellant (FC11) to arrhythmias produced by the bronchodilators,363 or excessive use and subsequent absorption of sympathometic compounds leading to fatal ventricular fibrillation.365 Some propellants also produce bronchoconstriction, especially in individuals with hyperreactive airways.366, 367 At that time, propellants were chosen not by considerations of toxicity, but by compatibility with the product being dispensed.366 Subsequently, the selection of low toxicity propellants362 and the withdrawal, in Great Britain, of over-the-counter preparations have reduced the hazards from these agents.
Multi-organ system failure secondary to difluoroethane toxicity in a patient “huffing” air duster: a case report
Published in Journal of Addictive Diseases, 2022
Benjamin Fogelson, David Qu, Milind Bhagat, Paul R Branca
Inhalants are a broad range of substances that include solvents, aerosols, gases, and nitrites that produce chemical vapors which may be “huffed” for psychoactive or euphoric effects. Of the many household inhalants, refrigerant-based propellant cleaners, incorrectly referred to as “canned air”, are commonly misused. The primary ingredient in most air dusters is 1,1-difluoroethane, a liquified fluorinated hydrocarbon. When inhaled and rapidly absorbed by the lungs, 1,1-difluoroethane depresses the central nervous system (CNS) within seconds and lasts a few minutes.5 Additional symptoms include lethargy, confusion, and loss of coordination. According to Tiscione et al, the CNS effects of 1,1-difluoroethane can be dangerously amplified in patients that abuse other CNS depressing substances such as alcohol.5 Repeated abuse of refrigerant-based propellant cleaners has been shown to cause significant toxic effects on other organ systems beyond the CNS, most notably the cardiovascular system (Table 1). Few published cases have presented an adult patient that survived multi-organ system failure secondary to 1,1-difluoroethane toxicity. We present a case of 1,1-difluoroethane toxicity leading to multi-organ system failure secondary to “huffing” air duster in a middle-aged woman that had complete recovery.
Investigation of propellant-free aqueous foams as pharmaceutical carrier systems
Published in Pharmaceutical Development and Technology, 2021
Dóra Farkas, Nikolett Kállai-Szabó, Ágnes Sárádi-Kesztyűs, Miléna Lengyel, Sabrina Magramane, Éva Kiss, István Antal
Both the design and evaluation of foams demand a complex approach, since the structure, physicochemical properties, dosage forms or complex drug-device combinations, as well as failure modes of the topical use are risk factors for a proper bioavailability (Miranda 2018). The monograph of medicated foams in the European Pharmacopeia 9.0 specifies three tests: the determination of relative foam density, the duration of expansion and, when applicable, sterility (Council of Europe 2016). Other than these, several examinations can be carried out on foams. In addition to a macroscopic evaluation, classifying them based on the pore size or fluidity, a microscopic description of the foams can be obtained by image analysis. The bubble size and bubble size distribution in the foam bulk can be determined with a dynamic laser speckle measurement sensor (Guerrero 2013), after stabilizing with quick freezing (Chang 1956), using a specific foam analyser instrument (Krüss GmbH 2019), or even from a simple microscopic picture (Farkas 2019). Foam stability (Leenerts and Myers 1957; Arzhavitina and Steckel 2010), its texture and consistency (Scott and Thompson 1952; Arzhavitina and Steckel 2010) are other informative descriptors. Although the difference between aerosol and propellant-free foams is significant, environmental aspects have to be considered too. Despite the low risk of potential human toxicity, such as for volatile organic chemical compounds, propellants still possess environmentally hazardous properties, like flammability or contribution to global warming (Tsai 2005).
Physical stability of dry powder inhaler formulations
Published in Expert Opinion on Drug Delivery, 2020
Nivedita Shetty, David Cipolla, Heejun Park, Qi Tony Zhou
Dry powder inhalers (DPIs) do not need propellants. They are portable devices that enable relatively easy administration of the formulation by the patient [20,21]. Due to the solid form and relative chemical stability of the powder, DPIs do not require cold chain storage [22]. In the last two decades, particle-engineering techniques such as spray drying, lyophilization, and supercritical fluid technology have been employed to produce DPI formulations [5]. Effects of physico-chemical properties of particulate systems such as particle size, density, porosity, surface morphology, inter-particle force, surface energy on the aerosol performance of DPIs have been extensively studied [23–26]. However, the solid-state characteristics and physical stability of the powder formulations in DPIs are frequently overlooked in the literature even though they are critical to the quality and performance of the inhalation products. In this review article, the physical stability of DPI formulations and its importance to the quality of DPIs are discussed.