CHAPTER 1

FTIR ANALYSIS OF DICLOFENAC SODIUM

Project work submitted

in partial fulfillment of the requirement

for the award of the Degree of

MASTER OF SCIENCE

In

PHYSICS

by

N. SAMPATH KUMAR

REGISTER NO: 2270734

DEPARTMENT OF PHYSICS

DWARAKA DOSS GOVERDHAN DOSS VAISHNAV COLLEGE

CHENNAI-600 106

APRIL 2010

BONAFIDE CERTIFICATE

This is to certify that the report entitled FTIR ANALYSIS OF DICLOFENAC SODIUM being submitted to the Madras University, Chennai, by Mr.N.SAMPATH KUMAR, for the partial fulfillment for the award of degree of M.Sc., (Physics) is a bonafied record of work carried out by him, under my guidance and supervision.

Place:

Date :

DECLARATION

I here by declare that this dissertation entitled FTIR ANALYSIS OF DICLOFENAC SODIUM is based on the original work done by me under the guidance and supervision of Mr.L.T.V.Vasanthagopalan, Lecturer, Department of Physics, D.G. Vaishnav College, Chennai-600 106 and has not formed the basis for the award of any degree, diploma, associateship or similar titles.

Place: N.SAMPATH KUMAR

Date: Reg. No: 2270734

D.G. Vaishnav College,

Chennai-600 106.

ACKNOWLEDGEMENT

I gratefully acknowledge Dr.S.Narasimhan, Principal, D.G.Vaishnav College, Chennai-600 106, for his kind encouragement throughout my course.

I wish to thank Dr.D.Uthra, Head, Department of Physics, D.G.Vaishnav College, Chennai- 600 106, for her support throughout my course.

My sincere thanks to Dr. B.Anita and Prof. B.Sylaja, Department of Physics, D.G.Vaishnav College, Chennai - 600 106.

I wish to express my sincere thanks to my guide Mr.L.T.V.Vasanthagopalan, Lecturer, Department of Physics, D.G.Vaishnav College, Chennai-600 106, who has suggested and guided me to select this project and shown keen interest during the course of the project.

I cordially thank my friend Mr.Shanmugapriyan, for his encouragement to my project work.

Date :

Place:(N.SAMPATH KUMAR)

CONTENTS

CHAPTER 1INTRODUCTION 1

1.1Introductionto Spectroscopy1

1.2Fourier Transform Infrared spectroscopy (FTIR)2

1.3Diclofenac Sodium4

1.4Phototoxicity and Photosensitivity 9

1.5Ecological problem 13

1.6FTIR study 14

1.7Scope of study 15

CHAPTER 2 INSTRUMENTATION OF FTIR 16

2.1Infrared spectroscopy 16

2.2Theory of infrared absorption17

2.3FTIR spectroscopy22

2.4Description of FTIR spectrophotometer 28

2.5Applications of FTIR 29

2.6Advantages of FTIR29

CHAPTER 3 RESULTS AND DISCUSSION31

3.1Conclusion38

LIST OF TABLES

1 Infrared region and corresponding wave numbers16

2 Vibrational frequencies for Normal and Sunlight condition34

3 Vibrational frequencies for Normal and ice point condition37

LIST OF FIGURES

1Chemical Structure of Diclofenac Sodium4

2Optical geometries of two conformational isomers6

3Photodegradation of Diclofenac sodium 12

4Bending and Stretching vibrations19

5Optical diagram of FTIR spectrophotometer24

CHAPTER 1

1.1 INTRODUCTION TO SPECTROSCOPY

Spectroscopy is studying the properties of matter through its interaction with different frequency components of the electromagnetic spectrum. Although almost all parts of the electromagnetic spectrum are used for studying matter in organic chemistry, we are mainly concerned with energy absorption from three or four regions: Ultraviolet and visible; infrared (IR); microwave; and radio frequency absorption.

Infrared spectroscopy is the subset of spectroscopy that deals with the infrared region of the electromagnetic spectrum. IR spectroscopy is basically vibrational spectroscopy. It covers a range of techniques, the most common being a form of absorption spectroscopy. As with all spectroscopic techniques, it can be used to identify compounds and investigate sample composition. A common laboratory instrument that uses this technique is an infrared spectrophotometer.

The infrared portion of the electromagnetic spectrum is usually divided into three regions; the near-, mid- and far- infrared, named for their relation to the visible spectrum. The far-infrared, approximately 400-10 cm-1 (1000-30 m), lying adjacent to the microwave region, has low energy and may be used for rotational spectroscopy. The mid-infrared, approximately 4000-400 cm-1 (30-2.5 m) may be used to study the fundamental vibrations and associated rotational-vibrational structure. The higher energy near-IR, approximately 14000-4000 cm-1 (2.5-0.8 m) can excite overtone or harmonic vibrations. The names and classifications of these subregions are merely conventions. They are neither strict divisions nor based on exact molecular or electromagnetic properties.

The infrared spectrum of a sample is recorded by passing a beam of infrared light through the sample. Examination of the transmitted light reveals how much energy was absorbed at each wavelength. This can be done with a monochromatic beam, which changes in wavelength over time, or by using a Fourier transform instrument to measure all wavelengths at once. From this, a transmittance or absorbance spectrum can be produced, showing at which IR wavelengths the sample absorbs. Analysis of these absorption characteristics reveals details about the molecular structure of the sample. When the frequency of the IR is the same as the vibrational frequency of a bond, absorption occurs.

This technique works almost exclusively on samples with covalent bonds. Simple spectra are obtained from samples with few IR active bonds and high levels of purity. More complex molecular structures lead to more absorption bands and more complex spectra. The technique has been used for the characterization of very complex mixtures.

1.2 FOURIER TRANSFORM INFRARED SPECTROSCOPY (FTIR)

FTIR is most useful for identifying chemicals that are either organic or inorganic. It can be utilized to quantitate some components of an unknown mixture. It can be applied to the analysis of solids, liquids, and gasses. The term Fourier Transform Infrared Spectroscopy (FTIR) refers to a fairly recent development in the manner in which the data is collected and converted from an interference pattern to a spectrum. Today's FTIR instruments are computerized which makes them faster and more sensitive than the older dispersive instruments.

Fourier transform infrared (FTIR) spectroscopy is a measurement technique for collecting infrared spectra. Instead of recording the amount of energy absorbed when the frequency of the infra-red light is varied (monochromator), the IR light is guided through an interferometer. After passing through the sample, the measured signal is the interferogram. Performing a Fourier transform on this signal data results in a spectrum identical to that from conventional (dispersive) infrared spectroscopy.

1.2.1 QUALITATIVE ANALYSIS

FTIR can be used to identify chemicals from spills, paints, polymers, coatings, drugs, and contaminants. FTIR is perhaps the most powerful tool for identifying types of chemical bonds (functional groups). The wavelength of light absorbed is characteristic of the chemical bond as can be seen in this annotated spectrum.

By interpreting the infrared absorption spectrum, the chemical bonds in a molecule can be determined. FTIR spectra of pure compounds are generally so unique that they are like a molecular "fingerprint". While organic compounds have very rich, detailed spectra, inorganic compounds are usually much simpler. For most common materials, the spectrum of an unknown can be identified by comparison to a library of known compounds. We have several infrared spectral libraries including on-line computer libraries. To identify less common materials, IR will need to be combined with nuclear magnetic resonance, mass spectrometry, emission spectroscopy, X-ray diffraction, and/or other techniques.

FTIR spectrometers are cheaper than conventional spectrometers because building an interferometer is easier than the fabrication of a monochromator. In addition, measurement of a single spectrum is faster for the FTIR technique because the information at all frequencies is collected simultaneously. This allows multiple samples to be collected and averaged together resulting in an improvement in sensitivity.

1.3 DICLOFENAC SODIUM

IUPAC Name: sodium (O-(2,6-dichloroanilino)phenyl)acetate. Molecular Formula: C14H10Cl2NNaO2. Molecular Weight: 318.1 g/mol.

Non-steroidal anti-inflammatory drugs (NSAIDs) comprise a large group of compounds that can be divided into two main sub-groups namely carboxylic acid and enolic acid sub-groups. Diclofenac sodium is a strong anti-inflammatory drug. Like other NSAIDs, diclofenac sodium has three basic properties-anti-inflammatory, antipyretic and analgesic. The anti-inflammatory action is due to inhibition of prostaglandin (PG) synthesis, and preventing action of other mediators of inflammation locally. The agent enhances recovery by abolishing inflammation, diminishing pain and providing symptomatic relief and well being to the patient.

Diclofenac sodium that consists of a phenylacetate group, a secondary amino group and a dichlorophenyl ring has limited water solubility especially in gastric juice. A possibility to overcome this limitation is the complexation with -cyclodextrin. -cyclodextrin is a cyclic oligosaccharide consisting of seven glucopyranose units that can be represented as truncated cone structure with the wide and narrow rims occupied by the secondary and primary hydroxyl group, respectively. The central cavities of these molecules are hydrophobic and thus are able to encapsulate a wide variety of molecules.

1.3.1 PHARMACOLOGY

The exact mechanism of action is not entirely known, but it is thought that the primary mechanism responsible for its anti-inflammatory, antipyretic, and analgesic action is inhibition of prostaglandin synthesis by inhibition of cyclooxygenase (COX) and it appears to inhibit DNA synthesis. Inhibition of COX also decreases prostaglandins in the epithelium of the stomach, making it more sensitive to corrosion by gastric acid. This is also the main side effect of diclofenac sodium. It has a low to moderate preference to block the COX-2-isoenzyme (approximately 10-fold) and is said to have therefore a somewhat lower incidence of gastrointestinal complaints than noted with aspirin.

Optimized geometries of two conformational isomers of Diclofenac sodium

There are two isomers of diclofenac sodium. Conformer-2 isomer of diclofenac sodium is more stable than the other isomer. The biological half-life of diclofenac sodium is about 1-2h, therefore it requires multiple dosing to maintain therapeutic drug blood level.

1.3.2 INDICATIONS

Diclofenac sodium is used for musculoskeletal complaints, especially arthritis, rheumatoid arthritis, Polymyositis, Dermatomyositis, osteoarthritis,dental pain, spondylarthritis, ankylosing spondylitis, and pain management in cases of kidney stones and gallstones. An additional indication is the treatment of acute migraines. Diclofenac sodium is used commonly to treat mild to moderate post-operative or post-traumatic pain, particularly when inflammation is also present, and is effective against menstrual pain and endometriosis. Diclofenac sodium is often used to treat chronic pain associated with cancer, particularly if inflammation is also present.

1.3.3 SIDE EFFECTS

Cardiac

Following the identification of increased risks of heart attacks with the selective COX-2 inhibitor, it is concluded that diclofenac sodium does increase the risk of myocardial infarction.

Gastrointestinal

Gastrointestinal complaints are most often noted. The development of ulceration and/or bleeding requires immediate termination of treatment with diclofenac sodium. Most patients receive an ulcer-protective drug as prophylaxis during long-term treatment.

Hepatic

Liver damage occurs infrequently, and is usually reversible. Hepatitis may occur rarely without any warning symptoms and may be fatal. Patients with osteoarthritis more often develop symptomatic liver disease than patients with rheumatoid arthritis. Liver function should be monitored regularly during long-term treatment. If used for the short term treatment of pain or fever, diclofenac sodium has not been found to be more hepatotoxic than other NSAIDs.

Renal

Studies showed that diclofenac sodium caused acute kidney failure in sensitive persons or animal species, and potentially during long term use. In non-sensitive persons resistance to side effects decreases with age. However, diclofenac sodium appears to have a different mechanism of renal toxicity.

1.3.4 FORMULATION

Diclofenac sodium is available in stomach acid resistant formulations (25 and 50 mg), fast disintegrating oral formulations (25 and 50 mg), slow- and controlled-release forms (75, 100 or 150 mg), suppositories (50 and 100 mg), and injectable forms (50 and 75 mg).

However, the solubility of diclofenac sodium is very limited in aqueous solutions around physiological pH. Parenteral or injectable formulations of diclofenac sodium have therefore necessitated the use of solubilizing additives such as propylene glycol.

1.3.5 INTERACTIONS WITH DIETARY SUPPLEMENTS

Calcium

Diclofenac sodium decreases the amount of calcium lost in the urine, which may help prevent bone loss in postmenopausal women.

L-tryptophan

Diclofenac sodium causes complex changes to L-tryptophan levels in the blood, but the clinical implications of this are unknown. More research is needed to determine whether supplementation with L-tryptophan is a good idea for people taking diclofenac.

Lithium

Lithium is a mineral that may be present in some supplements and is also used in large amounts to treat mood disorders such as manic-depression. Diclofenac sodium may inhibit the excretion of lithium from the body, resulting in higher blood levels of the mineral. Since minor changes in lithium blood levels can produce unwanted side effects, diclofenac sodium should be used with caution in people taking lithium supplements.

1.4 PHOTOTOXICITY AND PHOTOSENSITIVITY

Phototoxicity and photoallergy are the two major types of photosensitisation. Phototoxicity occurs more frequently than photoallergy and does not involve an immunological mechanism. Phototoxic reactions, which resemble severe sunburn and may even blister, are dose dependent for both drugs and sunlight. These reactions occur immediately after, or within a few hours of taking the drug and simultaneous exposure to radiation of the

appropriate wavelength and will subside if the drug is withdrawn and/or if possible the patient avoids excessive exposure to sunlight. Phototoxicity may cause damage to cells by modification of certain targets such as DNA, lipids and/or amino acids and proteins.

Drugs may be exposed to a variety of light conditions, including direct sunlight, filtered (window) sunlight and various artificial light sources during manufacture, storage, distribution and administration to the patient. Although the ultraviolet (UV) component of sunlight is considered the most problematic, exposure to fluorescent lighting for prolonged periods of time needs to be taken into consideration in terms of the spectral distribution of these light sources, which extends from 300nm to 3000nm. UV-C (200-280nm), UV-B (280-320nm) and UV-A (320-400nm) comprise the three regions of the UV-spectrum. Although eliminated from the earths surface by absorption by molecular oxygen and ozone, UV-C, which may cause adverse effects, is present in artificial light sources such as germicidal lamps and welding arcs. Although the UV-A reaches the earths surface to a greater extent than that of UV-B, it is the UV-B which causes sunburn and skin cancer. While sunlight and fluorescent light sources have a high output in the visible region of the spectrum (400-800 nm), the significant output in the UV-region must be noted for the fluorescent light sources. Most drugs absorb UV-C, while UV-B is responsible for the photoreactivity of drugs in the presence of sunlight and UV-A in addition to being absorbed by DNA, may cause photosensitisation reactions. In order to cause a reaction, the UV radiation must penetrate, whether it is the drug in the formulation or in the patient. The former is dependant on the transparency of the packaging. In the patient, although UV radiation shorter than 320nm penetrates the stratum corneum of the Caucasian skin, it must reach the absorbing drug molecule in the peripheral blood capillaries in order to illicit a photochemical response.

Studies on the photodegradation of drugs are relevant to the drug development process, because the photolysis products may have biological effects different from those of the parent compounds. This may explain, at least partially, the phototoxicity mechanism. Reports on cutaneous photosensitivity disorders provoked by new pharmaceuticals appear with increasing frequency.

A mechanistic study of the photodegradation is found in the recent literature. The major photoproducts of diclofenac sodium are carbazole derivatives (compounds 8Clcb and cb).

Assays in vitro performed with Diclofenac sodium and the photoproducts show positive photoxicity only for 8Clcb. Likewise, the analysis of the photophysical data are interpreted considering the participation of the triplet state of 8Clcb. Thermodynamic considerations as well as an observed quenching of triplet state as the concentration of 8Clcb is increased lead to formulate the formation of an excimer from which a radical ion could be formed. Dehalogenation is followed to yield an aryl radical and chloride anion.

In other words, irradiation with UVA light of the anti-inflammatory drug diclofenac sodium in aqueous buffer or methanol solution leads to sequential loss of both chlorine substituents and ring closure to carbazole-1-acetic acid as the major product. Minor products result from substitution by the solvent. Diclofenac sodium, after photodehalogenation (removal of both chlorine atoms) takes place, the carboxyl group remains intact which allows the photoproduct to be readily excreted. Drug concentration needs to be taken into consideration in all photosensitivity reactions and this involves the dosage of the drug concerned the higher the dose the higher the circulation concentration of the drug and the greater the potential for a photosensitivity reaction to occur. This needs to be taken into consideration when comparing the ability of diclofenac sodium to cause photosensitivity effects in patients.