PHARMACEUTICAL CHEISTRY
213
Dr.Abdulkareem
1
Class Meetings:
to be arranged
Office Hours:
As posted and by appointment
The study of pharmacologically active compounds with emphasis on chemical
structure, mode of action, and the relationships of these factors to therapeutic effects
in humans.
The majors classes of drugs discussed are various central and
autonomic nervous system agents, diuretics, antibiotics and antineoplastic agents.
The aims of this course :
1. to provide students with the basic of medicinal chemistry
2. to provide students understand the structure of medicinal chemistry.
3. to provide students with an understand of major classes of
medicinal chemicals and their modes of action4. to understand the drug, structure-activity-relationship theory
5.study stability, methods of qualitative, quantitative analysis ..
-There is a laboratory with this course
Aims
1. Identify compounds classes
2. Name according to IUPAC
3. Corelate structure to stability ,storage ,solubility, activity.drug
Instructional method :
Class lecture, questioning, group discussion, demonstration, case study.
COURSE CONTENT
- Non narcotic, narcotics.
- CNS depressants( general anesthetic, sedatives- hypnotics
Tranquillizers, antiepileptics )
- CNS stimulants (analeptics , xanthenes , amphetamines , antidepressants
- H 1, H2 antihistamines .
- Antidiabetics
- Local anesthetics .
- Cardiovascular drugs ( cardiac stimulants , antihypertensives, antianginals
- Antimicrobials (antibiotics, chemotherapy)
- Anti asthmatics
2
-
Corticosteroids
Vitamins
Hormones
route of drug administration
mechanism drug action
TEXTBOOKS
1. Derge ,R. F. Wilson and Gisvold's textbook of organic medicinal .
and pharmaceutical chemistry, 9th ed ,USA (1991)
2 .Korolkovas , A. Essnetials of medicinal chemistry 2 nd ed UAS (1988). .
3. Internet search
Grades
3 exams
first =20
Lab Final 30
-----------
second =25
third = 25
100
‫يعهىيات يهًه نهطانة‬
‫ انحضىر وانغٍاب عهٍه درجات‬-1
‫ انشهاده انًزضٍه ٌجة اٌ تعتًد يٍ اداره انكهٍه‬-2
‫ عدو تأدٌه انطانة اي اختثار ٌؤدي انى حزياٌ انطانة يٍ اندرجه‬-3
‫ يٍ اندرجه‬%22 ‫ فً حال وجىد عذر طثً ٌعاد االختثار يع خصى‬-4
‫ االنتزاو تانحضىر تًىعد انًحاضزه والٌسًح نهطانة تاندخىل تعد تدا انًحاضزه‬-5
‫ يشاركه انطانة فً انفصم يهًه‬-6
3
1. Drugs ( OTC , prescription )
2. Computer ( drug expire, order)
3. Patient counltation
4 . books refrences
Pharmaceutical drugs :
The course of pharmaceutical chemistry provides a study of different classes of
pharmaceutical compounds. This study includes the chemical structure of some
selected examples, pharmacological actions and medicnal uses, dosage forms,
major physicochemical properties, identity tests and methods of quantitative
analysis and structure activity relationships (SAR)
The following classes will be studied;
1-Analgesics ( narcotics and non- narcotics)
7-Antidiabetics
2-CNS depressants
8-Antimicrobial agents
3-CNS stimulants
9- Vitamins
4-Antihistamines
10-Corticosteroids
5-Local anesthetics
6-Cardiovascular
11- Hormones
4
Pharmaceutical dosage forms
• Capsules: Sustained Release, Enteric Coated
•Chapsticks
•Creams: topical, rectal, Vaginal disposable applicators,etc.
• Ear Drops: Solutions &Suspension
• Enemas
• Eye Drops: Sterile and Preservative Free
• Gels: Topical and Oral
• Injectables
• Liquids
• Mouth rinses
• Nasal Sprays+Solutions
• Non-Aerosol Sprays: Nasal, Oral, Topical and other
.Opthalmics
•Otics
• Patches
• Pellet Implants
• Powders
• Pulmonary Inhalation Preparations
•Suppositories: rectal, vaginal
•Suspensions
•Syrups: Pain Cocktails, Discontinued and Customized Cough Syrups, Other
•Tablets
•Troches (Sublingual)
• Urethral Inserts
•Vaginal Individualized Applicators
• Ointments
• Lotions
5
Route of administration
6
a) Enteral route (GIT tract)
1. Oral
2. Sublingual
3. Rectum
4. Inhalation
(b) Parenteral route (Systemic or blood)
1. Intravascular ( vein – artery )
2. Intramuscular
3. Subcutaneous
(A) Enteral Route: In this route the drug is placed in the Gastrointestinal Tract and then it absorbs to the
blood.This route is further classified into three
classes:
1-Oral Route: In this route the drug is placed in the mouth and Swallowed. It is also called per oral (p.o.)
Advantages of Oral Route
• Convenient - Can be self administered, pain free, easy to take
• Absorption - Takes place along the whole length of the gastro intestinal tract
• Cheap - Compared to most other parenteral routes
Disadvantages of Oral Route
• Sometimes inefficient - only part of the drug may be absorbed
• First-pass effect - drugs absorbed orally are initially transported to the
liver via the portal vein – drug destroyed
• Irritation to gastric mucosa – nausea and vomiting
• Destruction of drugs by gastric acid and digestive juices
• Effect too slow for emergencies
• Unpleasant taste of some drugs
• Unable to use in unconscious patient
7
First-pass effect:This is effect which occurs with oral route of administration. The first pass
effect is the term used for the hepatic metabolism of a pharmacological agent when it is
absorbed from the gut and delivered to the liver via the portal circulation. The greater the
first-pass effect, the less the agent will reach the systemic circulation when the agent is
administered orally.
Examples of drugs which undergo marked First Pass Effect:• Imipramine, Propranolol, • Lidocaine.
2-Sublingual: - drug is placed under the tongue. And it is taken without the use of water.
- disintegrates there and the absorption occurs in mouth. The tablets are small size
- eg. Nitroglycerine tablets
Advantages
• Rapid absorption:• Avoid first-pass effect.
Disadvantages
• Inconvenient: • Small Doses: - can be swallowed
-The drugs having unpleasant taste can
8
Buccal Route
In this route of administration the drug is kept in the buccal cavity where it
disintegrates and absorption occurs in the mouth.
3-Rectal Route ( suppository): Many drugs that are administered orally can also be administered rectally as asuppository.
In this form, a drug is mixed with a waxy substance that dissolves or liquefies after it is
inserted into the rectum.Because the rectum's wall is thin and its blood supply rich, the drug
is readily absorbed.
Advantages
1-people who cannot take a drug orally because they have nausea .
2-cannot swallow,or have restrictions on eating, as is required
3-after many surgical operations.
4-Drugs that are irritating in suppository form may have to be given by injection.
9
4-Vaginal Route:
Some drugs may be administered vaginally to women as a solution, tablet, cream,
gel,suppository, or ring. The drug is slowly absorbed through the vaginal wall. This route is
often used to give estrogen to women at menopause, because the drug helps prevent
thinning of the vaginal wall.
Advantages:1. Unconscious patients and children:-If the patient is unconscious
then it is not possible to give the drug orally. So in this situation the drug can be
given through rectal/urethral/vaginal route.
2. If patient is having nauseous or vomiting
Disadvantages:1. May cause irritation
2. Absorption may be variable.
Examples:- Suppositories , Vaginal Bogies
B- Parenteral Routes:In this route of administration the drug does not pass through the gastrointestinal tract. It
directly reaches to the blood.
It can further be classified into two classes:1. With injections:- in this class the drugs are administered with the
use of Injections e.g. Intravascular , Intramuscular ,Subcutaneous
2. Without injections: - in this class the drugs are administered without use of
injections.e.g. Inhalations. Epidermal –batches , sublinqual ,transdermal
12
With Injections:1. Intravascular:- vein or artery
In this route of administration the drug is directly taken into the blood with the help of
injection. Absorption phase is bypassed.
Advantages:1. Precise, accurate
2. Large quantities can be given, fairly pain free eg. Blood transfusion .
saline (NaCl) ,dextrose
3. Can be given to unconscious patients.
4. immediate onset of action
5. Drugs having unpleasant taste can be given.
Disadvantages:1. Pain at the site of injection.
2. Greater risk of adverse effects
3. High concentration attained rapidly
4.( Risk of embolism )
2. Intramuscular:In this route of administration the drug is given into the muscles with the help of injection.
Drug once reaches to the muscles,absorbs into the blood.
a. Very rapid absorption of drugs in aqueous solution
b. Depot and slow release preparations
c. Pain at injection sites for certain drugs
Without Injections:- Inhalation . Epidermal –batches , sublinqual ,transdermal
11
Inhalation
In this class the drug is administered to the blood without going to the gastrointestinal tract.
In this class the drug is not administered with the help of injections. In this administration
the drug is administered in the gaseous form.
Advantages:1. Rapid onset of action due to rapid access to circulation.
2. Pain free.
Examples :- Inhalers ( ventolin ) , Aerosols ( beconase)
.Local/Topical Route of Drug
AdministrationIn this route the drug is applied on the skin and mucous membrane for the
local action.
• Mucosal membranes (eye drops, antiseptic, sunscreen, callous
removal,nasal, etc.)
• Skin ,Dermal - Rubbing in of oil or ointment (local action).
• Transdermal - Absorption of drug through skin (systemic action) eg . angised
i. No first pass metabolism
ii. Drug must be potent
eg. Creams ,Gels , Lotions
12
h
13
Onset of ActionThe length of time needed for a medicine to give its action. This time varies for different
types of routes of administrations.
• Intravenous 30-60 seconds
• Inhalation
2-3
minutes
• Sublingual
3-5
minutes eg . angised
• Intramuscular 10-20 minutes
• Subcutaneous 15-30 minutes
• Rectal
5-30
minutes
• Oral
30-90
minutes
• Topical/transdermal (topical) variable (minutes to hours)
14
ANALGESICS
Definition
An analgesic is a CNS depressant which reliefs pain when it is Internally administered.
Most of analgesics may have antipyretic or anti-inflammatory action.
Classification
Analgesics are classified into :
a) Non-narcotic analgesics
b) Narcotic analgesics
A) Non-Narcotic Analgesics
a. Acetyl Salicylic acid
15
b.
Aniline derivatives : paracetamol
c. Anthranilic acid derivatives
. - Mefanamic acid (ponstan )
.Diclofenac sodium ( Voltaren )
f. Phenyl acetic acetic acid
eg. Ibuprofen (profinal )
Pharmacology
a.Aspirin
- It is an example of OTC drugs
- It has an analgesic (headache), antipyretic (fever), anti- inflammatory
(rheumatic arthritis) action.
- Recently, aspirin is used as antiplattlet agent to prevent blood clot formation
Side effects ; gastric (stomach ) Irritation, allergy
Contraindications ; patients having peptic ulcers and allergy
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Dosage forms
:either single or combined as tablets,
effervescence tablets.
b.Paracetamol
- an example of OTC drugs
- It is medicinally used as analgesic and antipyretic
-side effects Very low compared to aspirin
17
Dosage forms : either single or combined as tablets, syrups, and suppositories.
Non-steroidal anti-inflamatory [NS AI] drugs
c - Mefenamic acid (ponostan)
d - diclofenac sodium (voltaren)
e - Ibuprofen, ketoprofen
f - indomethacin ( indocid).
NSAI drugs are mainly used as anti-inflammatory agents(rheumatic arthritis,
rheumatism.
ketoprofen as analgesic (tooth pain , headache).
* Side effects : Gastric irritation
* Contraindications : Peptic ulcer
* Dosage forma : Tablets (diclofenac sodium, ibuprofen),
capsules (indomethacin, mefenamic acid, ketoprofen), injections
(diclofenac sodium, gel (diclofenac sodium), suppositories
(indomethacin).
externally applied analgesics
Examples : Menthol, Thymol, methylsalicylate, Camphor,
Externally used as creams, ointments, lotions
They act as counter Irritants in simple muscle pain
Physico chemical properties
Aspirin : Aspirin Is easily degraded by hydrolysis, in presence of moisture
into inactive and irritant acids.
MSAI Drugs
Water-insoluble except diclofenac sodium (water-soluble)
Paracetamol :Water-insoluble but soluble In Phenolic compound
Identity bests
Aspirin :
Ferric chloride test ——— >
+ve
(after hydrolysis)
Paracetamol ;Ferric chloride test ———— > +ve
Diazo test ——— > ve (after hydrolysis)
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B- Narcotic Analgesics
Opium
It Is the dried latex obtained from the un-ripe papaver capsules.
The major active constituents of opium are alkaloids, which are classified according to chemical
structure into :
1.
Phenanthrene alkaloids e.g. Morphine, Codeine
Codeine
2-
lsoqquinoline alkaloids e.g.
Papaverine
Structure activity relationships (SAR) of Morphine and its derivatives
19
-The phenanthrene ring structure is essential for analgesic activity.
-Saturation of phenyl ring or double bond at C7—C8 results in loss of activity
Substitution of R1 , R 2 by (H,H) gives morphine which is
a potent analgesic.
- Heroin : Increase the analgesic activity 10 times
An increase in activity in heroin, bstitution of R1,R2.=CH3CO
- substitution R1 by CH3 decreases the analgesic activity and
increases the antitussive (cough suppressant) activity (codeine)
Major Pharmacology and Medicinal uses
Morphine:
Very potent narcotic analgesic which has very rapid onset of action.
Medicinally,
it Is used as analgesic in severe pain as in cancer, bone
fractures, angina pectors, after surgical operation.... .etc.
Morphine has a potent muscle relaxant properties (as in renal colics).
Side effects : respiratory depression.
Repeated doses of morphine lead to drug addiction (drug misuse).
- Dispensing of morphine preparations should be under medical and
pharmaceutical control.
- Dosage forms : Injections , tablets.
Codeine
i
* It is less analgesic than morphine.
Medicinally, it is used as antitussive (cough suppressant ), and as
22
analgesic for slide pain.
Dispensing of codeine preparations should be, as morphine, under
medical and pharmaceutical control.
Dosage forms : single or combined as tablets, syrups and suppositories
Papaverine
It has no analgesic properties as morphine .
Medicinally it is used as muscle relaxant in renal, abdominal and bladder colics.
The drug may be used with other broncnodilators In bronchial asthma and
angina pectoris.
Dosage forms : single or combined as tablets, injections, suppositories.
Physicochenical properties :
Morphine, codeine and papaverine are basic compounds.
They form water soluble salts e.g.
Morphine ————> Morphine hydrochloride and morphine sulfate
Codeine
————> Codeine phosphate
Papaverine ————> Papaverine hydrochloride .
Identity Tests :
Marquis test ——-------> + ve
(morphine , codeine)
Ferric chloride test ———> + ve(only morphine)
Morphine substitutes
These are chemically synthetic compound having nearly the same
analgesic effect as morphine.
Properties of morphine substitute :
-They are used for mild and severe pain.
-They have less respiratory depressant properties than morphine
-They are dispensed under medical and pharmaceutical control as morphine .
Eg.
a.Pentazocine (Sosegon )
b. Pethidine
c. .Dextropropoxyphene (Algaphan)
21
Morphine antagonists :
- These drugs block the action of morphine at morphine receptors.
- They are used in the treatment of morphine and morphine substitutes addicts.
Eg.
a. Nalorphine
b. Naloxone
- theses drugs does not cause addiction
Morphine derivatives
Diacetyl morphine (Herroin)
-Herroin Is more potent than morphine
-The drug is no longer used due to high liability of drug addiction
-drug lead to euphoria and state of hallucination
Route of administration: snuffing, injection
Toxicity : respiratory depression , death.
Cough treatment
A- Cough Suppressants
They are used In dry and painful cough
Examples : a. Codeine
B-
b. Noscapine
c. Clobutinol (silomat )
Mucolytice_
They are used to facilitate expectoration by reducing sputum viscosity
Eg. Bromohexine (Bisolvon )
CEg.
Expectorants
: They expel sputum
Actifid , Diphenhydramine Expectorant
22
List of Analgesic Preparations
Mon narcotic analgesics
Aspirin
Aspegic
Adol
Revanin
Calpol
Panadol
Brufen
ProfinaI
Ponstan Gllfanan Proxen
Doloxene
narcotic analgesics
Algaphan
Sosegon
Morphine sulfate
Stadol , pethidine
Non-steroid, anti-inflammatory agents
Dolobid
Proxen
Voltaren
Aspirin
Tanderil
Indocid
23
Central nervous system (C NS ) depressant
1.
2.
3.
4.
General anesthetics
Sedatives and hypnotics
Tranquillizers
Antiepeileptics
1. General Anesthetics
Definition :
It is a drug which produces anesthesia ( loss of sensation ) during surgical operations.
a. Inhalational General Anesthetics
- Gases
eg. cyclopropane
- Volatile liquids eg. Ether
b.
Intravenous General Anesthetics ( Barbturates
eg. Thiopental sodium (Pentothal )
Major pharmacology, medicinal uses
-
General anesthetics are non selective CNS depressants.
Intravenous general anesthetic is generally used to induce ( start) anesthesia,
While inhaled general anesthetic is used to maintain ( continue ) anesthesia.
Intravenous general anesthetics have very rapid onset of action, but they
are of short duration.
Major side effects
are respiratory and cardiac depression.
Physicochemical Properties:
Ether
- Highly volatile liquid
- Highly inflammable liquid
- toxic and explosive
2.Sedatives and Hypnotics
Definition Drugs act on central nervous system ,
These drugs may produce either sedation or hypnosis
depending on dose of drug given.
Classification
a)
Phenobarbitone
( luminal)
b)
Aldehyde Chloral hydrate ( chloral)
c)
Benzodiazepam
.
(valium)
Structure - activity relationships (SAR of Barbiturates ):
Barbiturates are chemically synthetic compounds derived from barbituric
acid. They have the same ring, but of different substituents (R 1 , R2 ) at
C 5. Substitution of hydrogen atoms at C-5 by phenyl, ethyl,.... increases
the penetrating power to the brain with subsequent increase of sedative hypnotic activity The type of substituents at C-5 influence the onset and
duration of action. Therefore, barbiturates are classified into short,
intermediate and long acting compounds.
Introduction of -S- into the ring, increases the lypophilic character with a
very rapid onset of action.
Major pharmacology and medical uses
a.Barbiturates :
- Phenobarbitone is the most widely used derivative.
The drug may be medicinally used as sedative, hypnotic and antiepileptic
depending on the dose.
- Phenobarbitone : Is frequently used in insomnia
- Repeated doses of drug lead to drug habituation (drug abuse ).
However administration of large doses leads to death.
Addiction
psychcological - physiology
habituation psychcological
Side effects: respiratory depression
- Dosage forms : single or combined as tablets, injections,
suppositories, syrups.
b. Aldehydes
Eg. Chloral hydrate
25
- Medicinally, the drug is only used as hypnotic in insomnia
- Dosage form : Elixir
c. Benzodiazepan
Eg. Diazepam ( valium)
valium
-
Medicinaly, diazepam is used as sedative, hypnotic, tranquillizer,
Antiepileptic depending on the dose.
- It is indicated in anxiety and insomnia .
- Repeated doses lead to drug habituation (drug misuse).
- Dosage forms :
tablets, Injections.
D .Chlordiazepoxide ( Librium)
- Medicinally used as sedative and muscle relaxant.
- Dosage forms: single or combined as tablets.
Physicohemical Properties;
Phenobarbitone
- Weak acid
- Water insoluble but soluble in organic solvents
Form a basic salt (phenobarbitone sodium) wnich is water-soluble
Quantitative analysis : Alkalimetric non aqueous titration
26
3.Tranquillizers :
These are drugs which produce strong sedation of CNS
They are effective in control of severe excitation ( schizophrenia ) = double
personality
Eg.
Eg .
Phenothiazine derivatives
Chloropromazine ( largactil )
largactil
Benzodiazepines :
- Diazepam
-Chlorodiazepoxide
( valium )
( Librium)
Structure - activity relationships (SAR) of Phenothiazines
Unoxidized phenothiazine ring is necessary for activity.
-The best position of ring substitution is 2-positlon; Substitution
with electron with drawing group e.g. Cl, CF -, SCH3increases the activity.
-The three atom chain between position-10 and nitrogen atom
of amino group is necessary for optimum activity,
The dimethyl amino group is essential for activity.
27
Major pharmacology , medicinal uses
Chloropromazine:
Medicinally, the drug acts a major tranquillizer (schizophrenia,
psychoses) and antiemetic.
- Dosage forms : single or combined as tablets, syrups,
Injections, suppositories
and drops.
Physicochemical properties Chloropromzine
Basic compound:
Forms an acidic salt (chlorpromazine hydrochloride)
Chlorpromazine is very sensitive to oxidation giving Inactive red colored
product. Light, heat and heavy metals {iron ion) catalyze drug
degradation.
Chlorpromazine should be prepared In dark colored glass containers
Quantitative analysis Acidimetric non aqueous titration
28
4, Antiepileptics
These are drugs which control epilepsy (grandmal and petitmal epilepsy).
a. phenobarbitone :
eg. phenytoin ( epanutin)
phenytoin
b Clonazepam ( Revotril )
c.Carbamazepine ( Tegretol )
Major pharmacology and medicinal uses
Phenytoin
- The drug is widely used as antiepileptic in grandmal epilepsy.
- Phenytoin is a serious drug which may produce toxic symptoms on
prolong medical use.
-
The level of drug should be monitored (Therapeutic drug monitoring)
(TDM) in blood of epileptic patients to:
a. Avoid toxic and subtherapeutic drug concentration In blood.
b. Ensure optimum therapeutic level of drug in the blood
-TDM is also applied for other drugs such phenobarbitone,
diazepam,
carbamazepine, clonazepam.
Dosage forms : single and combined as tablets and Injections.
29
Physicochemical properties
phenytoin
Weak acid
Water-Insoluble
Forms salt (phenytoin sodium)
List of anti- Depressants
Chloral
Valium
Librium
Ativan
Equanil Serepax Largactil Melleril
Atarax Epanutin
Revotril
Tegretol
Local Anesthetics
Definition
- These are drugs that produce loss of sensation in a given area of the
body.
Types of L A
1234-
-
teeth
topical on the skin
spinal - labor
peripheral minor surgical operation
The local anesthetics are useful for temporary relief of localized
pain In dentistry, minor burns, hemorrhoids and to initiate
anesthesia to minor surgical operations.
- properties An Ideal local anesthetic :
1. Should be of rapid onset of action ( fast ) and short duration( end
quickly ) .
2. Should be of low systemic ( blood ) absorption .
3. Can be given in different dosage forms (creams, lotions, sprays.)
4. Should be non-toxic.
Classification
1. P-Aminobenzoic acid derivatives
32
a. benzocaine ( ester )
b.Procaine ( ester )
2. Anilide
Lidocaine ( xylocaine)
Ester
Amide
oxygen O - c=o
nitrogen N c=o
- amide
( destroy ) metabolite blood or tissue
=
liver
Identity tests
Benzocaine, procaine
-------- Diazo test ———> +ve
Quantitative analysis
Procaine, Lidocaine
Acidimetric non aqueous titration
List of some local anesthetics
31
Xylocaine Injections
Xylocaine Ointaent, spray
Cichonal
Ointment
ANTI - HISTAMIMES
Definition
These are drugs which antagonize the action of histamine on certain receptors.
Histamine
Histamine is a chemical substance which Is present In mast cells in tissues and
organs. The level of histamine In blood increases only during anaphylactic
reactions.
Pharmacologically action of histamine : ?


In blood – body Produces vasodilation of blood vessels with an
increase of blood flow (redness)
In the lung : produces contraction of bronchial muscles (asthma) and
- In the stomach : -increases gastric secretion.( peptic ulcer )
Pharmacological studies Indicates that histamine has two types of receptors:
 -H1 receptors in blood vessels+ lung
 -H2 receptors in gastric mucosa ( stomach )
Interaction of histamine with these receptors gives the above
32
pharmacological actions.
Classification of
As previously discussed, antihistamines can be classified into:
1.
H1- antihistamines
2.
H2- antihistamines
H1 - antihistamines
H 1 antihistamines block the action of histamine on the H1 receptors in the
blood vessles and bronchi. Examples
a.Aminoalkyl ether
eg. Diphenhydramine ( Benadryl)
b.Propylamine :Chlorpheniramine (chlorohistol , piriton)
piriton
c. Phenothiazine
33
phenergan
d. Others
eg.
zyrtec
34
Structure activity relationships (SAR) of H1 antihistamines of aminoalkyl
ethers and propylamines
- Aryl group (phenyl, substituted phenyl, heteroaryl..,) on the carbon atom is
essential for activity ( ar1 ,ar2)
- Amino group (diethylamino) on the terminal nitrogen atom is necessary for
maximum activity.
- Intermediate chain should be of maximum 2 carbons for optimum activity.
- Medicinally 1H-antihistamines are indicated in treatment of
different types allergy e.g.
o
o
o
o
o
skin allergy (urticaria),
nasal allergy (rhinitis),
eye allergy (itching),
motion sickness
insect bites.
- Side effects :
1- Drowsiness - dizyness
2- increase appetite ( eating )
- Dosage forms Tablets,drops, suppositories,
syrups, injections, creams.
Physicochemical properties
- Diphenhydramine, chlorpheniramine and promethazine are weak bases.
-They form salts diphenhydramine hydrochloride and chlorpheniramine
maleate. and promethazine hydrochloride
-
Promethazine is sensitive to oxidation.
- Quantitative analysis
Acidimetric non-aqueous titration
H2 –antihistamines
Cemetidine
( stomach )
(Tagamet)
35
Rhanitidine
(zantac )
Famotidine
(Pepcid )
Omeprazole
(Losec ,Gasec , proton )
Structure - activity relationships (SAR) of -H-antihistamines
Imidazole ring or other heterocyclic ring (furan ring) should be present for
maximum H 2 antagonist activity.
-Hydrophilic group attached to terminal nitrogen Is necessary
-Thioether link between the ring and the terminal nitrogen atom is essential
for activity .
Major pharmacology, medicinal uses
Medicinally, 2H-antihlstamines are used as ulcer-healing agents in
peptic ulcer (gastric, doudenal) together with other drugs
e.g. antacids, protective colloids, antispasmodics.
- Side effects
: Diarrhea, rashes
- Dosage farms : Tablets, injections
3---Histamine Inhibitors (Mast cell stabilizers) Example
Cromolyn Sodium (Intal )
- These drugs inhibit the release of histamine from mast cells.
- Medicinally, they are used for the prophylaxis of asthma attack.
- Dosage forms : Spincaps
- Route of administration : Inhalation
Drugs : Antistine Chlorohistol Tavegyl
36
Allerfin
Piriton
Periactin ( eating )
Avil
Phenergan
Polaramine
Benadryl
zaditen
(Teldane x
Antidiabetics
Definition
These are drugs which control glucose blood level in diabetic patients.
Diabetes Mellitus
Diabetes Mellitus is a metabolic disease wnich is characterised by
hyperglycemia and glucosuria due to deficiency of insulin secretion.
Glucose blood level
- Normal glucose blood level is 80-120 mg % or (4-6 m mol / 1)
- Mild diabetics 250 mg% ,
- severe diabetics (> 250 mg%)
Types of diabetics
a. type 1 ;Insulin-dependent injection
Patients should be only treated with Insulin due to absolute
lack of insulin.
b.
type 11 :non-insulin dependent
Patients can be treated with insulin and oral hypoglycemics or
only with oral hypoglycemics.
Mode of action of insulin
Insulin regulates glucose blood level by :
1. Increase passage of glucose from plasma (blood) to the cells
2. Increase glycogensis
3. Decrease the conversion of fats to glucose.
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