Looking At What Asthma Is Biology Essay


Asthma is one of the general chronic inflammatory diseases that disturb the carriage of air to and from the lungs as a result of a swollen airway. The swelling of the airway causes a high level of irritation which increases the risk of an allergic reaction by making it more difficult for the passage of air to and from the lung. The symptoms of asthma are; wheezing - a hiss sound produce during breathing, coughing, shortness of breath and chest stiffness. All these symptoms are usually occur at night and early morning.

1.1 Classification of Asthma

Child-Onset Asthma

Adult-Onset Asthma

Occupational Asthma

Nocturnal Asthma

Cough-Induced Asthma

Exercise-Induced Asthma

Steroid-Resistant Asthma

1.2 Causes of Asthma




Tobacco Smoking

Babies at risk (Babies born by Caesarean have a 20% chances of having asthma)

1.3 Treatment for Asthma

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Long-term control medicines such as Inhaled corticosteroids.

Short-term control medicine: asthma can be treated by the use of medicines such as a beta - 2 agonists for example; pressurized metered dose inhaler, dry powder inhaler

1.4 Pressurized Metered Dose Inhaler

Inhaled formulation has been used for a very long time ago. It has it origin associated with smoking of "datura" formulation in India over four thousand (4,000) years ago. The first pressurized metered dose inhaler was developed in 1955 by Riker Laboratories, now a subsidiary of 3M Healthcare 17. Prior to this development, asthma medication has been delivered by using a squeeze bulb nebulizer which is weak, unreliable and too big to deliver an effective drug to the lungs, this lead to the research and development of pressurized metered dose inhaler. In 1956, there was another development in metered dose inhaler; this gave birth to two products which are Medihaler-Ept containing epinephrine and the Medihaler-Iso containing isoproterenol. The two products are β agonist whose function is to ensure a short term relief from the asthma symptoms. However, asthma treatment has now been replaced by Salbutamol which is more effective, efficient and has fewer side effects 18.

Pressurized metered dose inhaler (pMDI) can be described as an aerosol inhaler or puffer which is used to deliver drug directly into the lungs. This drug or medicine is used for the treatment of asthma, chronic obstructive pulmonary disease and other respiratory and lung diseases that are characterized by blockage of airflow and shortness of breath. Pressurized metered dose inhaler is made up of therapeutic active ingredients which are dissolved in a mixture of solvent and propellant in a compact pressurized aerosol dispenser. The propellant and the co solvent form the basic composition which determines the internal pressure of an inhalation aerosol. They are different from other drug product in terms of their formulation, container, stability and other manufacture-in -process.

1.5 Components of pressurized metered dose inhaler

Pressurised metal canister: this carries the solution or suspension of the medicine

3 Cans

Figure 13: shows the picture of a coated canister

Plastic Mouthpiece: this is the channel or medium where the medicines passes through from the mouth of the patient to the lung 19

Metering Valve: this controls the quantity of formulation to be dispensed 19

Spray Orifice

http://solutions.3m.com/3MContentRetrievalAPI/BlobServlet?locale=en_WW&lmd=1216415621000&assetId=1180602188733&assetType=MMM_Image&blobAttribute=ImageFile Figure 13: shows the diagram of pressurized metered dose inhaler 20

Note that the design of the container of pressurized metered dose inhaler and it protective packaging constitute the drug these also determines the efficacy and performance of the drug. Also, the container will administer a fixed proportion of the medication to the patient without contamination or exposure of the remaining medication or dose.

1.6 Physical and Chemical Assessment Test for Pressurized Metered Dose Inhaler 20a

Moisture content test

Weight of the content

Drug content (assay)

Impurities/degradation products

Particle size distribution

Leak rate

Dose content uniformity

Pack integrity

Valve delivery

Spray pattern and plume geometry

Priming/re-priming studies

Extractable and leachable testing

Microbiology testing

In May, 2009 3M been a forefront leader in inhaled drug delivery and technologies discovered two innovations for the delivery of pressurized metered dose inhaler. The aim of these new discoveries was to improve the pressurized metered dose inhaler systems in terms of it performance and capacity which are:

3MTM Plasma Coating Technology 20b

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The plasma coating technology has helped to provide an optically balanced system for pressurized metered dose inhaler. The plasma coating is made up of inorganic layer that prevents degradation coupled with fluorine layer to decrease the surface energy of the container closure system (CCS). Also the 3MTM plasma coating technology has assisted in solving the problem of hyrofluoroalkane (HFA) one of the ingredients of the inhaler by making a covering layer on the container which addresses the issue of degradation, deposition and corrosion. This coating material can be used for plastics and metals because some active pharmaceutical ingredients (API) are liable to degradation and corrosion when they come in contact with metal oxides.

1.7.2 Benefits of the plasma coating technologies:

The plasma coating assist to decrease the susceptible interaction of the inhalation ingredient with the valves and canisters

This addresses the issue of degradation, deposition and corrosion by providing an effective barrier or resistance

It enhances the stability of product life

The plasma coating technology can also be used for coating complex component such as plastics and metals

1.8 .1 3MTM Face Seal Valve 20c

The face seal valve has assist to get rid of the use to prime an inhaler by withdrawing the dose as the inhaler is ejected. The principle of the valve of a pressurized metered dose inhaler is based on the dose retention which is achieved by withdrawing the dose when the valve stem is released. This principle has lead to loss of dose. The aim of introducing the face seal valve is to improve the performance and capacity of the valve by helping the patient to receive a full dose of their medication.

1.8.2 Benefit of the Face Seal ValveRetention Valve

Face seal valve helps to get rid of prime

It assist to deliver an accurate and precise dose

Pressure can be compressed into the valve

Figure 14 shows the 3MTM Face Seal Valve

1.9 Dry Powder Inhaler

Dry powder inhaler can be described as another aerosol inhaler which is used for the treatment of respiratory diseases such as asthma, emphysema, bronchitis and chronic obstructive pulmonary. The dry powder inhaler is another innovation with a slight difference from the pressurized metered dose inhaler. The medicine or drug in dry powder inhaler is transported in form of a dry powder directly into the lungs 21. This idea was brought in order to adjust the pressurized metered dose inhaler system to chlorofluorocarbon free system by using hydrofluoroalkanes also to transport a larger quantity of therapeutics to the respiratory tract 22. The container and the packaging of dry powder inhaler will determine the performance and the efficacy of the drug. One of the main differences between pressurized metered dose inhaler and dry powder inhaler is that energy is required for dispersion of the drug and this energy can be gotten from the patient's inspiration, compressed gas and motor-driven impeller while pressurized metered dose inhaler uses the energy stored in by the liquefied gas propellant. Dry powder inhaler is more likely exposed to contamination from moisture or microbial activities both in use and after use unlike that of pressurized metered dose inhaler.


Figure 14: shows a well labelled diagram of dry powder inhaler 22

Chapter 2

2.1 Introduction to Plastics

Plastic is a synthetic or semi-synthetic organic amorphous solid. They are majorly polymers from either natural or synthetic compounds with large molecular mass a. Plastic have improved every day need such as in packaging of food and drugs, household utensils, computers, phones , toys e. t. c. It usage and production are increased daily which is predicted to be 300 million tonnes by 2010 b. Rubbers and plastics are often used as drug delivery device, primary and secondary packing.

2.2 Attributes of Plastic c

1. It is versatile

2. It doesn't break easily

3. It is a good insulator of heat

4. It is relatively cheap and strong

5. It is not heavy (in terms of weight)

6. It can be easily shaped and colored

7. It can resist chemical and moisture attack

There are numerous different types of plastic, which can be categorised based on their starting monomer, length of polymer chains and the type of modifying compounds added. Plastics can be classified based on the chemical process used for is synthesis, such as condensation and cross-linking. It can also be classified based on it numerous physical properties for example, density, tensile strength, transition temperature e. t. c. Below is the classification of plastic:

Figure 7: shows the classification of plastic d

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LDPE: low density polyethylene

MDPE: medium density polyethylene

HDPE: high density polyethylene

2.3.1 Thermoplastics

A thermoplastic is one of the major classifications of plastic. It is also known as thermosoftening plastic. It is made from polymer resins such as polyethylene and polystyrene which have the ability to mold and remold repeatedly. It turns to a homogenized liquid when it is heated and hardens when cooled. The essential feature of thermoplastics is that it can be recycled e. Thermoplastic polymer chains are related through a weak Van der Waals force, strong dipole - dipole interaction and hydrogen bonding f.


Figure 8: shows the graph stress strain of one of the thermoplastic material

2.3.2 List of test carried out on thermoplastic includes:

Tensile tests: this is a technical test method set by an international organisation: ISO 527 -1/-2 and ASTMD 638 to determine the tensile strength of a thermoplastic. However, this test is quiet sensitive and it needs a reasonable accuracy of ± 1micrometer for the dilatometer.

Flexural tests: this test is carried out to determine the rigidity of thermoplastic

Pendulum impact test: are used to examine the effect of the character of materials at a high deformation speeds. Also, it can be used to detect the energy needed to break a material by taking measurement of it height to which the corresponding pendulum hammer rises after the impact of the test.

2.4.1 Thermosetting Plastic g

Thermoset is a polymeric material that normally has a network that is cross linked. It is also known as thermosetting resin. Once the shape is formed, it cannot be reversed. They are totally cured by a chemical reaction such as irradiation: electron beam processing which may need heat at 200 o C above and pressure. Thermoset polymers are not soluble; they cannot be recycled after forming a shape expect as filler. One of the advantages of thermosetting is that they keep their strength and shape when heated. They are used to produce permanent components and shape.

2.4.2 The Thermosetting process

The result of the curing process changes the resin into plastic or rubber by a cross-linking process. The presence of energy and catalyst are required to form a chemical reaction with the resin at the active site which forms a rigid 3 - D structure. Also, the chemical reaction or cross - linking of the plastic monomer will result into a higher molecular weight and melting point for the plastic. An example of thermosetting plastics includes; epoxies, polyesters, silicones and phenolics. They main application of thermosetting plastic is used in the manufacture of electrical gadget such as

2.5 Elastomer

Elastomer is a polymer which can be referred to as elastic of polymer or rubber. It is an amorphous polymer whose temperature exceeds the glass transition. At room temperature, rubbers are soft and they can be deformable. The main applications of elastomer are seals, adhesives and molded flexible par.

Identification Test for Plastics and Rubbers

Simple test


Solubility test

Burning characteristic

Odour recognition



Halogen test

Fluorinated Ethylene Polymer (FEP).

Fluorinated Ethylene Polymer (FEP) coating reduces drug deposition to improve chemical and physical stability.

3M Product Number

Diameter Coated Canisters (FEP)


0.872" (22.15mm) brimful capacity 15ml

A64461 + O-ring

0.918" (23.32mm) brimful capacity 16ml


0.872" (22.15mm) brimful capacity 19ml

FTIR spectra and mechanical strength analysis of some selected rubbernext term derivatives

S. Gunasekaran, R.K. Natarajana and A. Kala

Chapter 3: History and Introduction of Infrared

3.0 History of Infrared Spectrum

Infrared (IR) is part of an electromagnetic spectrum / radiation 1. The infrared spectra are collected from a unique and special instrument called Infrared Spectrometer 2. It wavelength is between visible radiation and microwave which extends beyond the red light. The range of IR wavelength is 700 nm to 300µm 1.

Figure 1 shows the electromagnetic spectrum or radiation 2

Infrared region of the electromagnetic spectrum was first discovered in 1800 by a British astronomer named Sir William Herschel. The discovery of infrared by Sir William Herschel paved way for fast development and research on the technique of infrared spectroscopy 3. One of the development of infrared after it discovery in 1800 was the construction of the first mid infrared spectrometer in 1835 4. The second development of infrared was it applications in astronomy such as examining the emission spectrum of the sun 5 and in physical 6, organic and atmospheric chemistry 7 within ninety (90) years after the discovery of infrared 8. Abney and Festing took the photograph of the absorption spectra for fifty - two (52) compounds and correlated absorption bands along with specific organic groups in the molecule 9. Infrared spectroscopy is a good and reliable technique which is largely used to obtain qualitative information on the molecular structure of samples in any of the physical state which are solid, liquid or gaseous state.

3.1 Advantages / Uses of Infrared Spectrometer 2

Infrared spectrometer is sensitive

Infrared spectra are fast and simple to run

Infrared is used to test for the purity of a compound

Infrared spectroscopy is used for identifying organic substances

Infrared is used to collect related information on the structure of a compound

3.2 Properties of Infrared 11

Chemical image can be mapped

Materials are mainly organic compounds

Strong absorption of glass, water and CO2

Resolution is between 10 - 20 µm while the lateral confocal is not possible

Frequency range is between 4000 - 400 cm-1 (for a typical laboratory instrument)

Physical property or effect: absorption of molecule and changing of the dipole moment (strong signals O-H, N-H etc.)

Sample preparation: optical thickness (transmission mode) or sample contact (attenuated total reflection) mode necessary, dispersion for drift etc.

3.3 Application of Infrared Spectroscopy 12: infrared spectroscopy can be applied in the following areas:

Oil industry

Paper industry

Textiles industry

Biological analysis

Finger print analysis

Chemical industrial analysis

Polymers analysis e.g. polymers present in plastics

Pharmaceutical analysis: used for analysing orally inhaled and nasal drug product

Medical analysis e.g. transition between the various structure of DNA, characterising stages of breast cancer 8

Figure 3: shows the infrared grouping (13a)

3.4 Principles of Infrared Spectroscopy 12

Infrared spectroscopy is an important technique in the identification of polymers. It is based on the principle that molecules vibrate and these molecules can absorb energy in the infrared region.

An equation is derived which shows relationship between the vibrational frequency (v) for two atomic system having two masses m1 and m2, the force constant (k) and the reduced mass (µ) as:



is the vibrational frequency / Hz


is the force constant / Nm-1


is the reduced mass / g or kg



is the reduced mass / g or kg


is the atomic mass 1 / g or kg


is the atomic mass 2 / g or kg


Infrared spectrum shows the relationship between the transmission and wavelength (cm-1). Absorption can only be attained when the molecule has a higher vibrational state at a particular frequency. Vibrational energy levels are quantised and molecules (usually in the ground vibrational state) are excited to a higher vibrational level by absorption of a quantum of IR radiation 11.

With a Fourier transform-infrared spectroscopy, the infrared wavelength from a polychromatic source can be measured at the same time. An interferogram is collected at the detector; this is moved to the infrared spectrum through a Fourier transformation. Normally, the spectrum is collected within seconds.

Figure 4: shows the schematic diagram of Fourier transform-infrared spectrometer 12

3.5 Detector of a Fourier transform-infrared spectrometer includes;

Thermal detectors for example thermocouple and bolometer

Pyroelectric detectors for example triglycine sulphate

Photoconducting detector; for example MCT (mercury cadmium telluride), fast response and very sensitive

4.0 Chapter 4: Instrumentation of Infrared Spectroscopy

4.1 Instrumentation of Infrared Spectroscopy by PerkinElmer 12a

The 1600 Fourier transform infrared spectrometer is one of the products from PerkinElmer which is very reliable, simple to use and it cheap. It is a single beam scanning Michelson interferometer.

Perkin Elmer PE 1600 FTIR

Figure 5: shows the picture of a PerkinElmer 1600 Fourier tranform infrared spectrometer

Table 1: shows the function of each component in the 1600 Fourier transform infrared:


LiTaO3 or DTGS

Abscissa accuracy:

0.01 cm-1 to 370 cm-1

Signal to noise ratio:

this is preferable to 0.1% transmittance peak to peak with 4cm-1 resistance and 1min acquisition


the resolution of PE 1600 FTIR is between 2 cm-1 to 64 cm-1

Scan time:

the scan period for PE 1600 FTIR is 4 seconds


RS-232C (2), Centronics

4.2 Instrumentation of Infrared Spectroscopy by Fisher Thermo Scientific 12b

The Nicolet iS10 Fourier transform infrared spectrometer is one of the products of thermo scientific. Part of the benefit of this fully graded spectrometer is it precision and accuracy in the area of verification and identification of samples. It is very fast to operate and it breaks down laboratory data collection to the lowest form.

4.2.1 Description of Nicolet iS10Fourier transforms infrared spectrometerImage  3

It is simple and cheap to use

It optical system which consists of the sealed and desiccated unit. It function is to prevent the instrument from humidity and solvent vapour

It applicable for analytical services and forensic duties

Figure 6: shows the picture of a Nicolet iS10Fourier transform infrared spectrometer

4.3 Library compilation of infrared by Nicodom 12c

Nicodom ltd produces a unique library compilation of about 800 infrared spectra for polymers and other related compounds. The aim of producing the library compilation of the infrared was for easy identification of polymers and other related compound by using Nicolet Fourier transform - near infrared spectrometer and OMNIC search software. The Nicodom infrared spectra is between the range of 4.20 - 11.00 cm-1 for polymers, monomers, plasticizers, lubricants, antidegradants (antioxidants, light stabilizers, polyvinylchloride stabilizers), burning retarders, antistatic agents, blowing agents, coloring agents, pigments, optical whitening's, fillers and other compounds in this category. The spectra are printed in logarithmic scale (Log 1/R or absorbance). The spectra were acquired by Thermo Nicolet FTNIR spectrometers, the sample in a powdery form were prepared in a glass vials in reflectance mode; clear liquids were collected in transmittance with a transflectance mirror.

2.3.1 Details of the Library compilation of infrared by Nicodom

Name: it is either the literature name or the general name given to the sample by the polymer chemist that comes up in this section

Type of material: this section gives details of class of polymer the sample falls into such as copolymer, polymer ally, terpolymer, block polymer, softening agent etc.

Abbreviation: this section handles the allocation of the proper abbreviation for each polymer. For example; the abbreviation of polyvinylchloride is given as PVC

Commercial title: this section has stored information on the commercial non chemical name of each sample; e. g. Nylon, Buna etc.

Comment: this section gives further details about the sample such as the physical state of the sample, density, molecular weight, viscosity etc.

Figure 7: shows the sampling methods in Fourier transform infrared 13

4.4 Sample Preparation for Infrared Spectroscopy

Samples for infrared spectroscopy are prepared based on the available information of the sample in terms of it physical and chemical stability. Usually, samples are prepared by mulling the sample powder in liquid paraffin (Nujol) or by grinding the sample with potassium bromide (KBr) powder. Some base containing hydrochloride may interchange the halogen (e.g. chlorine) with potassium bromide powder, using the mulling technique for the sample preparation will be better.

In other cases, usually mulling agents have bands in there spectrum which may mask the bands in the sample spectrum. Potassium bromide on the other hand doesn't have bands in their own spectrum which will not mask the sample's spectrum, through these; the halide disk loses less information. Samples in the halide powder should be homogenous with a particle size that will not scatter the spectrum.

The capacity of the infrared absorption spectrum is determined by the number of molecules in the beam whereas; the capacity of the potassium bromide is determined by the quantity and homogeneity of the sample in the potassium bromide powder. After the sample has been prepared in the appropriate disk, the infrared light passes through the sample. The sample analyzed is identified by comparing it infrared spectrum with spectra from a similar sample in a library 14.

4.5 Sampling Preparation Technique for Infrared Spectroscopy

4.5.1 PerkinElmer's Attenuated Total Reflectance (ATR):

This is an infrared sampling technique that produces a qualitative and quantitative data coupled with its ability to involve in other infrared sampling technique. It is used for surface analysis of soft samples and liquids e.g. plastic and rubber component. It principle is based on the total reflection of the infrared radiation that happens within the high refractive index crystal. Sampling depth of ATR is given as amplitude of the evanescent wave decreases exponentially with depth (x) into the sample which is 13:

Where dp is the sampling depth which is defined by the Harrick Equation

Where Harrick Equation state:



Is the refractive index of sample


Is the refractive index of crystal


Is the wavelength


Is the angle of incidence

Figure 8: shows the spectra taken from a PerkinElmer's Fourier transform infrared software called "preview mode" 14a

4.5.2 Infrared microscope:

This can be used to analyse small sample, both transmission and reflection technique. It is used to detect defects in compounds and crystals, these defects are rendered visible by using infrared microscope 15. Characteristics of Infrared Microscope

It is not expensive

It averagely sensitive

It has medium resolution of ca. 1 µm

It is not fully quantitative (strain fields)

It is used to evaluate thermal coupling within component

It can be used for analysis of samples that have medium defect

Figure 9: shows the picture of infrared thermal imaging microscope 15a

Infrared can mainly be divided into two parts based on their diffraction - limited microscopy, they are follows 15b:

Optical visualization and infrared spectroscopic data collection

Focal plane array detection for infrared chemical imaging

Infrared microscopic images needs a Perkin Elmer spotlight system which contains a vital linear array (16 x 1 detector elements) mercury - cadmium - telluride (MCT) detector.

4.5.3 Use of potassium bromide (KBr):

This technique is used for sample that can be crushed or ground. The sample once ground is compressed in a disk for analysis. (Details above)

Figure 10: shows the sample preparation with potassium bromide 16

4.5.4 Specular Reflectance Spectroscopy:

This is a non destructive sample preparation method for surface measurement e.g. analysis of thin layers on metal such as crystal faces and monolithic polymers. This happens when the reflected angle of infrared radiation is the same as the angle of incidence. Kramers-Kronig transform is used to obtain spectra from the absorbance when the sample is homogeneous and optically thick. This sample preparation technique is used on Hyperion microscope and Nexus spectrometer 17a.

Figure 11 shows the diagram of a specular reflectance spectroscopy

4.5.5 Diffuse Reflectance Spectroscopy:

It involves the use of many light sample interaction. The principle behind diffuse reflectance is that there is a reflection of energy from the incident beam which penetrates on one or more particles. It is specially used for analysis of powder, rough surface and solid that is intractable. Sample should be ground to a particle size 2 of to 5 microns before the analyses starts, this help to decrease the quantity of specularly reflected light. 17b.


Figure 12: shows the light sample interactions of diffuse reflectance spectroscopy