its about Ultraviolet and visible spectrophotometer and Its application in pharmaceuticals & cosmetics in year 2017-18

1. Ultraviolet and visible
spectrophotometer and Its
application in pharmaceuticals &
cosmetics.
Presented by: NIKHIL NANDAKUMAR KADAM
roll no : 153010003
PGFDC

2. SR.
NO
content
1 introduction
2 principle
3 instrumentation
4 application
5 application in pharmaceuticals
6 application in cosmetics
INDEX

3. Introduction:
 The word spectroscopy implies that we will use the
electromagnetic spectrum to gain information about
organic molecules. The modifier ultraviolet means that
the information will come from a specific region of the
electromagnetic spectrum called the ultraviolet region
(190 to 400 nm U.V. Region and 400 to 800 nm Visible
Region) .

4. INTRODUCTION
• UV visible spectroscopy is also known as
electronic spectroscopy in which the amount
of light absorbed at each wavelength of UV
and visible regions of electromagnetic
spectrum is measured.
• As it involves the promotion of the electrons
from the ground state to Excited state
• The absorption of electromagnetic
radiations by the molecules leads to
molecular excitation

5.  The interaction between radiation
and matter is a fascinating area in its
own right. Most drug molecules
absorb radiation in the ultraviolet
region of the spectrum although
some are coloured and thus absorb
radiation in the visible region, e.g. a
substance with a blue colour absorbs
radiation in the red region of the
spectrum.
prof. aza 5

6. Theoretical principles
If a molecule is allowed to interact with the EMR of a proper frequency,
the energy of the molecule is raised from one level to a higher one; we say
that absorption of radiation takes place. In order for absorption to occur,
the energy difference between the two energy level must be equal to the
energy of the photon absorbed
E2 – E1 = hυ where E1 is energy of lower level and E2 is the energy of
upper level
- This energy jump from one level to another is called transition
- The graph of the light absorption against the frequency is called
absorption spectra.
- Visible and Ultraviolet light provides enough energy for electronic
transition there for called electronic spectra.

7. -On absorption of energy by a molecule in the ultraviolet region, changes are
produced in the electronic energy of the molecule due to transitions of
valence electrons in the molecule.
E
6* Anti-bonding
π* Anti-bonding
n Non-bonding
π Bonding
6 Bonding

9. Types of transitions:
1) 6 6*: A transitions of electrons from a bonding sigma orbital
to the higher energy antibonding orbitals. ( eg. Alkane). Sigma
bonds are, in general, very strong, there fore they require high
energy for the transitions and this transitions requires very short
wavelength (near about 150 nm)
2) n 6*: This transition involves saturated compounds with one
hetero atom with unshared pair of electrons (n electrons).
Corresponding band appears at 180-200 nm.
3) π π*: This transition is available in compounds with un-
saturation (eg. Alkene). Corresponding band appears at 170-190
nm.
4) n π*: This type of transitions are shown by the unsaturated
molecules containing one or more hetero atoms. (O, N, S)

10. 5) Conjugated system: In conjugated dienes, the π orbitals of the
separate alkene group combine to give new orbitals i.e. the two new
bonding orbitals which are designated π1 and π2 and new two anti-
bonding orbitals designated as π3* and π4*. So for the π2 π3*
transition very low energy is requires corresponding to the higher
wavelength.

11. Some important terms:
1) Chromophore: It is a group of molecules, which is responsible for
the absorption of light by molecules. It is conjugated dienes. It is
minimum structural requirements for the absorption of radiation in UV
range.
2) Auxochrome: It is a saturated group containing unshared electrons
which when attached to a Chromophore changes both intensity as well as
the wavelength of the absorption maxima. e.g. OH, NH2, Cl etc.
3) λ-max: It is a wavelength at which there is a maximum absorption or
absorption intensity. It is a physical constant and characteristic of structure
and so useful for identification of compounds. It is independent of
concentration.
4) Bathochromic shift: The shifting of absorption to a longer
wavelength due to substitution or solvent is called as bathochromic shift.
It is also called as Red shift. e.g., λmax of Ascorbic acid=243nm, λmax of
Ascorbic acid in alkali medium=299nm.

12. 5) Hypsochromic shift (Blue shift): Shifting of λmax to lower value or left
hand side due to substitution, solvent, pH etc is called as Hypsochromic
shift. e.g. λmax of Phenol in basic media=297nm, λmax of Phenol in acidic
media=277nm.
6) Hyperchromism: Increase in absorption intensity (e) due to solvent,
pH or some other factors called hyperchromic effect.
7) Hypochromism : Decrease in absorption intensity due to substituent,
solvent, pH etc. called hypochromic effect.
8) A1%
1cm (A one percent one centimeter): Is the absorbance of the
solution having concentration 1 gm per 100 ml of the solution.
9) Molar absorptivity (ε): Is the absorbance of the solution having
concentration gm.mol.weight/1000 ml of the solution. [ε = (A1%
1cm X
Mol. Wt.)/10]
10) Transmittance (T): is the ratio of IT/I0 and % transmittance (%T) is
given by %T=100 IT/I0

13. Principles of
UV - Visible
Spectroscopy

14. PRINCIPLE
UV spectroscopy obeys the Beer-Lambert law, which states that:
when monochromatic light passes through a transparent medium,
the rate of decrease of intensity of light with respect to
thickness and concentration of absorbing species is proportional
to intensity of light.
A = log (I0/I) = ECL
Where,
A = absorbance
I0 = intensity of light incident upon sample cell
I = intensity of light leaving sample cell
C = molar concentration of solute
L = length of sample cell (cm.)
E = molar absorptivity

15. Principle
 The UV radiation region extends from 10 nm
to 400 nm and the visible radiation region
extends from 400 nm to 800 nm.
Near UV Region: 200 nm to 400 nm
Far UV Region: below 200 nm
 Far UV spectroscopy is studied under vacuum
condition.The common solvent used for
preparing sample to be analyzed is either ethyl
alcohol or hexane.

16. UV Visible spectrophotometer

17. Instrumention
Components of UV-visible
spectrophotometer
• Lamp
• Filter
• Monochromator
• Beam splitter/mirror
• Sample holder
• Detector
• Recorder

18. Lamps –
 Two types of lamps are used.
 Deuterium lamp/ Tungsten filament lamp.
 Deuterium lamp is useful for the wavelength region
between 160 to 375nm.
 Tungsten filament lamp is useful for the wavelength
region between 350 to 2500nm.

19. filter
 Device that allow the radiation of required
wavelength to pass through it
 Two types of filter
 Absorption filter
 Interference filter
 Absorption filter absorb unwanted wavelength
and allow passing through them a wavelength of
interest
 Interference filter use for obtaining narrow
band of wavelength

20. Monochromator
• It is a device use for wavelength selector in
spectrophotometer
• There are two types of monochromators
Monochromator
Grating
Reflection Transmission
Prism

21. Detector:-
• The device which detects energy of an incident
beam and of transmitted beam.
( It converts radiant energy ( photons ) into a electrical
signal.The photocell and phototube are the simplest
photo detectors, producing current proportional to the
intensity of the light striking them.)
• The difference between the energy of these
two beam indicate energy absorb by analyte
Three types of detector
1. Barrier layer cell
2. A photocell
3. photo multiplier tube

22. Sample holder:-
sample can be store in cuvettes
made of quartz or fused silica
Display devices : the data from a detector are display by a
readout device , such as an analog meter , a light beam,
reflector on a scale, or digital display or LCD.
The output can also be transmitted to a computer or printer.

23. Single beam spectrophotometer

24. Double beam spectrophotometer

25. Single beam spectrophotometer
• A single beam of light which can pass through one
solution at a time ( sample or reference)
 Simple configuration (less complicated)
 Cheaper instrument
Double beam spectrophotometer
• A single beam of light spilt into two separate beam.
One pass through the sample and another pass through
reference
 Complex configuration
 Higher cost ,high stability and low sensitivity

26. Concept of Chromophore and Auxochrome in
the UV spectroscopy
chromophore
The functional groups containing multiple bonds
capable of absorbing radiations above 200 nm due to n
–›л* and л–›л* transitions.
e.g.NO2, N=O,C=O,C=C,C=S, etc
Auxochrome
The functional group with non-bonding
electrons that does not absorb radiation in
near UV-region but when attached to a
chromophore alters the wavelength and
intensity of absorption

27.  Blue shift(n-л*)(Hypsochromic shift)
• Increasing polarity of solvent – better solvation of
electron pairs (n level has lower energy)
• Peak shifts to the blue (more energetic)
• 30 nm (hydrogen bond energy)
 Red shift(n-л*and л–л*) (Bathochromic shift)
• Increasing polarity of solvent, then increase the
attractive polarization forces between solvent and
decreases the energy of the excited states with then
later grater
• Peaks shift to the red
• 5 nm

28. Advantages and disadvantages
 Advantages
• Simple and inexpensive experimentation.
• Most organic molecules absorb UV/Vis light.
• Quantitative(beer`s law).
 Disadvantages
• Mixtures of molecules can be a problem due to overlap
(hence, routinely significant sample preparation).
• Spectra are not highly specific for particular molecules.
• Expensive instrumentation

29. There are four types of
shift are observed in UV
 Bathochromic shift (red
shift); a shift to longer
wavelength ; lower energy.
 Hyperchromic effect ; an
increase in intensity
 Hypsochromic shift(blue
shift);shift to shorter
wavelength; higher energy
 Hypochromic effect ; a
decrease in intensity

30. Detection of impurities
UV absorption spectroscopy is one of the best methods for
determination of impurities in organic molecules. Additional peaks
can be observed due to impurities in the sample and it can be
compared with that of standard raw material. By also measuring the
absorbance at specific wavelength, the impurities can be detected.
Structure elucidation of organic compound
From the location of peaks and combination of peaks UV
spectroscopy elucidate structure of organic molecules.
I.E. 1) The presence or absence of unsaturation.
2) The presence of hetero atoms.

31. Chemical kinetics
kinetics of reaction can also be studied
using UV spectroscopy. The UV radiation is passed
through the reaction cell and the absorbance changes can
be observed.
Determination of structure of organic compound
example;- element , functional group.
Determine strength of hydrogen bond.

32. Applications in pharmaceutical analysis
 A robust, workhorse method for the
quantification of drugs in
formulations where there is no
interference from excipients.
 Determination of the pKa values of
some drugs.
 Determination of partition
coefficients and solubilities of drugs.
prof. aza 32

33.  Used to determine the release of
drugs from formulations with time,
e.g. in dissolution testing.
 Can be used to monitor the reaction
kinetics of drug degradation.
 The UV spectrum of a drug is often
used as one of a number of
pharmacopoeial identity checks.
prof. aza 33

34. Application in pharmaceutical
1. Determination of aspirin and salicylic acid in
Aspirin tablet by UV spectrometry.
2.Determination of morphin and heroin by UV
Spectrophotometry.
3. Many a drug are either is form of raw material
Or in form of formulation ,they can be assayed by
Making a suitable solution of drug in solvent and
Measuring at specific wavelength

35. Application in cosmetics
Sun protection factor determination of marketed
sunscreen Formulation by In-vitro method using
UV-VISIBLE spectrometer

36. ESTIMATION OF PARACETAMOL TABLET.
Standards :- paracetamol tablet (contain not less
than 95%and not more than 105% of
stated amount of paracetamol.
Uniformity of tablet :-
weigh 20 tablet individually and calculate from the average
weight as per requirement under tablet.

37. Assay:
1.Weight and powder 20 tablet, a quantity of the powder
equivalent to about 0.15g of paracetamol.
2. Add 50ml of 0.1N NaOH dil with 100ml water
3.Shake for 15 min and add sufficient water to produce
200 ml.
4. Mix filter and dilute 10ml of filtrate to 100 ml with
water.
5. To that 10 ml of resulting solution add 10 ml of 0.1N
NaOH, dilute to 100 ml with water and mix .
6. Measure the absorbance of resulting solution at the
maximum at about 257nm.

38. Concentration Of
Paracetamol
Absorbance
0 0
10 0.654
20 1.2925
30 1.938
40 2.521
50 2.698
60 3.173
Result and conclusion

39. U.V. Spectra of Paracetamol (PCM)

40. Structure Illustration of organic compounds.
 UV spectroscopy is useful in the structure elucidation of organic molecules, the presence or
absence of unsaturation, the presence of hetero atoms.
 From the location of peaks and combination of peaks, it can be concluded that whether the
compound is saturated or unsaturated, hetero atoms are present or not etc.
 Quantitative analysis : UV absorption spectroscopy can be used for the
quantitative determination of compounds that absorb UV radiation.
 Qualitative analysis: UV absorption spectroscopy can characterize those types
of compounds which absorbs UV radiation. Identification is done by comparing
the absorption spectrum with the spectra of known compounds.

41. U.V. Spectra's of Ibuprofen

42. Detection of Functional Groups
 This technique is used to detect the presence or
absence of functional group in the compound
 Absence of a band at particular wavelength
regarded as an evidence for absence of
particular group

43. Quantitative analysis of pharmaceutical substances
 Many drugs are either in the form of raw material or in
the form of formulation. They can be assayed by making
a suitable solution of the drug in a solvent and measuring
the absorbance at specific wavelength.
 Diazepam tablet can be analyzed by 0.5% H2SO4 in
methanol at the wavelength 284 nm.

44. Examination of Polynuclear Hydrocarbons
 Benzene and Polynuclear hydrocarbons have characteristic
spectra in ultraviolet and visible region. Thus identification of
Polynuclear hydrocarbons can be made by comparison with
the spectra of known Polynuclear compounds.
 Polynuclear hydrocarbons are the Hydrocarbon molecule with
two or more closed rings; examples are naphthalene, C10H8,
with two benzene rings side by side, or diphenyl, (C6H5)2,
with two bond-connected benzene rings. Also known as
polycyclic hydrocarbon.

45. Naphthalene DIPHENYL

46. Molecular weight determination
 Molecular weights of compounds can be measured
spectrophotometrically by preparing the suitable derivatives
of these compounds.
 For example, if we want to determine the molecular weight of
amine then it is converted in to amine picrate. Then known
concentration of amine picrate is dissolved in a litre
of solution and its optical density is measured at λmax 380
nm.

47. APPLICATIONS:
1. Qualitative Analysis:
The UV spectra of most compounds are of limited value for
qualitative analysis as compared to IR and Mass spectra. Qualitative
analytical use of UV spectra has largely involved λ-max and
absorptivities, occasionally includes absorption minima. In
pharmacopoeias, absorption ratios have found use in identity tests, and are
referred to as Q-values in USP.
2. Quantitative Analysis:
UV spectroscopy is perhaps the most widely used spectroscopic
techniques for the quantitative analysis of chemical substances as pure
materials and as components of dosage forms.

48. Use of UV/visible spectrophotometry to
determine pKa values(ACID DISSOCIATION CONSTANT)
 Where a pH-dependent UV shift is
produced, it is possible to use it to
determine the pKa (ACID DISSOCIATION CONSTANT) of
the ionisable group responsible for
the shift.
 In the case of phenylephrine, the
pKa value of the phenolic group can
be determined conveniently from the
absorbance at 292 nm since
48

49.  The wavelength used for analysis is
one where there is the greatest
difference between the ionised and
un-ionised species.
 An approximate knowledge of the
pKa value is required to select a
suitable pH value, within ± 1 of the
pKa value (ACID DISSOCIATION CONSTANT), for
measurement of absorbance
prof. aza 49

50.  For accurate determination
measurement is made at a number of
closely spaced pH values.
 It should be noted that if the acid or
base undergoes a shift to lower
absorbance and shorter wavelength
with increasing pH the log term above
is subtracted; this situation is less
common in drug molecules.
prof. aza 50

51. Phenylephrine: hydroxyl group
auxochrome
 The chromophore of phenylephrine is not
extended but its structure includes a
phenolic hydroxyl group. The phenolic
group functions as an auxochrome under
both acidic and alkaline conditions. Under
acidic conditions it has two lone pairs of
electrons, which can interact with the
benzene ring and under basic conditions it
has three.
51

52. UV spectrum of phenylephrine under
acidic and basic conditions, 273→292 nm
52

53.  figure shows the bathochromic and
hyperchromic shift in the spectrum of
phenylephrine, which occurs when 0.1 M
NaOH is used as a solvent instead of 0.1
M HC1.
 Under acidic conditions the λ max is at
273 and has an A (1%, 1 cm) value of 110
and under alkaline conditions the λ max
is a 292 nm and has an A (1%, 1 cm) value
of 182.
prof. aza 53

59. Sun Protection Factor(SPF)

63. Limitations
 Only moderately selective.The selectivity
of the method depends on the
chromophore of the individual drugs, e.g
a coloured drug with an extended
chromophore is more distinctive than a
drug with a simple benzene ring
chromophore
 Not readily applicable to the analysis of
mixtures.
prof. aza 63

64. Conclusion
 Despite being costly uv-visible
spectrophotometry is a valid method used
for determining the absorption or
transmission of UV/VIS light by a sample.
 It measures concentration of absorbing
materials based on developed calibration
curves of the material.
 the purpose in vitro SPF determination method is
simple, rapid, and can used for many types of
cosmetics formulation.

65. REFERENCES

66. Online Resources
 http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/S
pectrpy/UV-Vis/spectrum.htmlm
 http://teaching.shu.ac.uk/hwb/chemistry/tutorials/molspec/u
vvisab1.html
 http://www.slideshare.net/search/slideshow?searchfrom=hea
der&q=cosmetics

67. Book References:
1. Sharma. Y.R. Elementary Organic Spectroscopy.
First edition .S.Chand Publisher; 2010.
2. Chatwal G.R. Instrumental methods of chemical
analysis. First edition. Himalaya Publisher; 2010.
3. www.chem.agilent.com/Library/applications/uv3
1.pdf.

68. COSMETICS BOOKS REFERENCE