Proteins as targets for drugs
Roger McFadden in Introducing Pharmacology, 2019
This chapter focuses on the four key protein targets for drugs, namely receptors, ion channels, enzymes and carrier proteins. Drugs target and bind to proteins and, via a complex series of consequential events, this produces a therapeutic effect, perhaps reducing inflammation and relieving pain or lowering cholesterol levels. Many drugs mimic chemical chemical messengers so it is important to understand their function in order to appreciate how those drugs work. A drug binds to a receptor because the drug’s molecular structure is similar in shape to that of the natural chemical messenger the body produces to target that receptor. As the drug salbutamol is similar in shape to adrenaline, it also binds to adrenaline receptors and produces the same effect as adrenaline, i.e. bronchodilation. A drug similar in shape to a natural chemical messenger will bind to the same receptor binding site as that messenger–in fact, competing against the chemical messenger for the binding site.
Hyperkalaemia
Sherif Gonem, Ian Pavord in Diagnosis in Acute Medicine, 2017
The mechanisms of hyperkalaemia are as follows: excessive potassium intake; inadequate renal potassium excretion; and redistribution of potassium from the intracellular to the extracellular space. Since the vast majority of potassium is stored in the intracellular compartment, hyperkalaemia may reflect the redistribution of potassium into the extracellular space, rather than increased total body potassium. Severe hyperkalaemia must be corrected as a matter of urgency, due to its potential to cause life-threatening cardiac arrhythmias, culminating in asystole. The treatment priorities are as follows: protect against cardiac arrhythmias; and lower the serum potassium concentration. The danger is more pronounced when potassium levels rise acutely. Nebulised salbutamol acts to shift potassium into the intracellular compartment, due to its b-agonist effects.Correction of metabolic acidosis, if present, with IV sodium bicarbonate may also serve to lower the serum potassium concentration by causing redistribution of potassium into the intracellular compartment.
Understanding lung function and disease
Zoë Rawles in Essential Knowledge and Skills for Healthcare Assistants and Assistant Practitioners, 2019
Many healthcare assistants (HCAs) are being asked to perform lung function testing to assist the nurse in the chronic disease clinic managing patients with respiratory disease. This chapter provides an overview of the anatomy and physiology of the respiratory system and common respiratory diseases to enhance HCAs understanding and enable them to perform lung function testing more efficiently and accurately. Asthma is very common, often misunderstood and often poorly managed. Various tests can be used to diagnose asthma, but there is no gold standard test available yet. Tests available include serial peak flow measurements, spirometry and assessment of reversibility with bronchodilators such as salbutamol. Chronic obstructive pulmonary disease (COPD) is usually associated with smoking, and because smoking levels are much higher in some disadvantaged sectors of the community, especially in people who have mental health issues, these people tend to be disproportionately affected by COPD compared with the rest of the population.
The use of response surface methodology for the formulation and optimization of salbutamol sulfate hydrophilic matrix sustained release tablets
Published in Pharmaceutical Development and Technology, 2012
Faith A. Chaibva, Roderick B. Walker
The objective of this study was to develop a hydrophilic matrix formulation with in vitro release characteristics similar to Asthalin® tablets and that would sustain the release of salbutamol sulfate over a 12-h period. A central composite design was used as the framework for manufacturing formulations that may be used to understand the relationships between polymer levels and in vitro release characteristics. Tablets were manufactured using wet granulation with Surelease® as the granulating fluid and different levels of Methocel® K100M, xanthan gum, and Carbopol® 974P as matrix-forming materials. In vitro dissolution testing was conducted using USP Apparatus 3 and samples were analyzed using a validated reversed-phase HPLC method. The results revealed that the levels and types of polymers had a significant impact on the rate of drug release from these formulations and that it was possible to optimize the levels of matrix-forming polymers to achieve the desired release characteristics. Statistical design and response surface methodology have been successfully used to understand and optimize formulation factors and interactions that impact the in vitro release characteristics of salbutamol sulfate from a potential multisource sustained release dosage form.
Quantifying the Degree of Disorder in Micronized Salbutamol Sulfate Using Moisture Sorption Analysis
Published in Drug Development and Industrial Pharmacy, 2007
Matthias Gorny, Markus Jakobs, Viktoriya Mykhaylova, Nora Anne Urbanetz
Salbutamol sulfate is often micronized for use in dry powder inhalers. Therefore, it is of high interest to quantify the amorphous amount. It was investigated whether moisture sorption is able to measure the amorphous content of salbutamol sulfate. Different mixtures of amorphous and crystalline salbutamol sulfate were analyzed by moisture sorption. The amorphous material was obtained by spray drying. The measurement results were used to plot a calibration curve, which was used to quantify the amorphous amount in micronized salbutamol sulfate.
Levosalbutamol in the treatment of asthma
Published in Expert Opinion on Pharmacotherapy, 2006
With the exception of levosalbutamol, all of the β2-agonists that are currently in use are racemic mixtures that are composed in equal amounts of (R)- and (S)-enantiomers. Clinical and mechanistic studies have demonstrated that (R)-salbutamol alone provides the β2-agonist activity that is needed for the relief of bronchoconstriction, as well as the β2-adrenergically mediated side effects. (S)-Salbutamol, on the other hand, has minimal binding affinity for the β2-receptor, indicating that its effects are likely to be mediated through another site. Furthermore, there is evidence that (S)-salbutamol opposes the desirable effects of (R)-salbutamol in the racemic mixture and contributes to the development of characteristic features of asthma, such as airway obstruction, bronchial hyperresponsiveness and airway inflammation. Evidence from clinical studies shows delayed recovery from exacerbation of asthma by patients who are exposed to high concentrations of (S)-salbutamol.
Related Knowledge Centers
- Beta Adrenergic Receptor
- Chronic Obstructive Pulmonary Disease
- Amino Alcohols
- Nh
- Ethanolamines
- Bronchodilating Agent
- Phenethylamines