Comprehensive Guide to Pharmaceutical Drugs and Analytical Chemistry
Diuretics
Drugs promoting urine output are known as diuretic drugs, which refer only to those agents that act directly on the kidneys. These drugs primarily increase the excretion of water and ions like sodium (Na+), chloride (Cl-, or bicarbonates HCO3-) from the body. Glomerular filtration, tubular reabsorption, and tubular secretion in kidneys determine the excretion of substances. They are employed in the treatment of various disorders like diabetes insipidus, nephrotic syndrome, hypertension, nutritional edema, edema of pregnancy, and liver cirrhosis. They also decrease the intracellular and cerebrospinal fluid pressure.
Examples of diuretics:
- Acetazolamide
- Furosemide
- Bumetanide
Acetazolamide
Acetazolamide is the prototype carbonic anhydrase inhibitor. This type of diuretic inhibits the carbonic anhydrase enzyme in the membrane and cytoplasm of epithelial cells.
Uses:
- Acetazolamide is self-limiting in nature.
- It produces adverse effects like acidosis and hypokalemia.
Stability and Storage Conditions: It can be stored up to 48 months. It should not be stored above 25° C. It should be stored in the original pack in order to protect from light and moisture.
Types of Formulations:
- Capsules
- Tablets
Popular Brand Names:
- Diamox
- Diamox Sequels
Furosemide
Furosemide is a benzole-sulfonamide-furan with fast onset and short duration of action. It is used for treating edema and chronic renal insufficiency.
Uses:
It is used for the treatment of edema related to congestive heart failure, liver cirrhosis, and renal disease. It is also used either alone or with other antihypertensive agents for the management of hypertension.
Stability and Storage Conditions: It should be kept at room temperature from 59°F (15°C) and 86° F (30°C). This drug should be kept away from light.
Antiviral Agents
Antiviral agents are used for treating viral infections. Similar to antibiotics for bacteria, specific antivirals are effective against specific viruses. Antiviral drugs, instead of destroying their target pathogen, inhibit their development. Since antiviral drugs are harmless to the host, they can be used to treat infections.
Acyclovir
Acyclovir is a nucleotide analog antiviral that is used for treating infections like herpes simplex, herpes zoster, herpes labialis, and acute herpetic keratitis.
It is the first-line drug to be used in the treatment of infections caused by these viruses.
Chemical Name: 2-Amino-1,9-dihydro-9-((2-hydroxyethoxy)methyl)-3H-purin-6-one
Uses:
- Acyclovir cream with hydrocortisone is used in recurrent herpes labialis, and shortening lesion healing time in 6 years and older patients.
- Acyclovir ophthalmic ointment is used in acute herpetic keratitis.
- Acyclovir oral tablets, capsules, and suspensions are used in herpes zoster, genital herpes, and chicken pox.
- Acyclovir buccal tablet is used in recurrent herpes labialis.
Antifungal Drugs
The drugs which are used in the treatment of fungal infections are called antifungal agents.
Classification of Antifungal Agents:
- Antibiotics, e.g. amphotericin-B, griseofulvin, nystatin.
- Pyrimidine derivatives, e.g. 5-flucytosine.
- Azoles/ Imidazoles e.g. clotrimazole, miconazole, ketoconazole.
- Allylamines, e.g. terbinafine
- Thiocarbanilic acid derivatives e.g. tolnaflate
- Phenolic compounds e.g. salicylic acid
- Diamidines e.g. stilbamidine.
- Dyes e.g. Gention voilet, malachite green
- Unsaturated fatty acids undecylenic acid
Ketoconazole
It is an imidazole derivative.
Chemical Name: 1-Acetyl-4-(4-[[2-(2,4-dichlorophenyl)-2(1H-imidazole-1-ylmeth- yl)-1,3-dioxolan-4-yl] methoxy] phenyl] piperazine.
Other Medical Terms and Definitions
Hypoglycemic drugs: Drugs used to treat diabetes mellitus by decreasing glucose levels in the blood.
Causative agent of tuberculosis: Mycobacterium tuberculosis.
Cystitis: The abnormality of urinary tract infection.
Symptoms of diabetes: Feeling very thirsty, blurred vision, feeling tired, urinating more often.
Analgesic: A drug that reduces pain.
UTI: Urinary Tract Infection.
Types of diabetes mellitus:
- Type 1 Insulin dependent
- Type 2 Non-insulin dependent
INH: Isoniazid
NSAIDs examples: Aspirin, Ibuprofen, naproxen, diclofenac.
Diabetes: The abnormality of pancreatic islets occurs in Diabetes.
MAOIs: Monoamine oxidase inhibitors.
Heart arrhythmia: The disturbance of rhythm.
Symptoms of hypertension: Severe headaches, chest pain, dizziness, nausea, vomiting.
Angina pectoris: Chest pain that keeps coming back.
IDDM: Insulin-dependent diabetes mellitus
PABA: Para amino benzoic acid
Insomnia: A sleep disorder in which you have trouble falling or staying asleep.
Normal range of Blood pressure: 120/80mm hg
Normal range of blood sugar levels: 70 mg/dl-100mg/dl.
Three-Membered Heterocyclic Compounds
These heterocyclic compounds contain three atoms which may be saturated or unsaturated. Based on the number of heteroatoms present, we can further classify them into two categories:
Heterocyclic Compounds with One Heteroatom
As the name suggests, it has one heteroatom present in its ring.
Examples: Aziridine, Oxirane, Thiirane, Azirine, Oxirene and Thiirene
Heterocyclic Compounds with More Than One Heteroatom
As the name suggests, it has more than one heteroatom present in its ring. The heteroatom atom in the ring can be the same or different.
Examples: Diaziridine and Oxiaziridine
Anesthetics
Anesthetics are drugs that are used to induce anesthesia, which is a temporary loss of sensation or awareness. There are two main types of anesthetics: local anesthetics and general anesthetics.
Local anesthetics block the sensation of pain in a specific area of the body. They are often used for dental procedures, minor surgery, and injections. General anesthetics cause a loss of consciousness and a general loss of sensation throughout the body. They are used for major surgery, childbirth, and other procedures that require the patient to be completely unconscious.
Thiopental Sodium
Chemical name: sodium 5-ethyl-5-pentan-2-yl-2-sulfanylidene-1,3-diazinane-4,6-dione
Uses: They are used to treat convulsions, and reduce intracranial pressure. Thiopental sodium may be employed in the ICU to provide sedation for patients requiring mechanical ventilation or other invasive procedures.
Stability and storage conditions: It should be stored at 22°C. Thiopental remains stable and sterile for 6 days and well beyond 7 days at 3°C.
Types of formulations:
- Injection
- Powder
- Solution
Brand names:
- Thiojex
- Pentone
- Pentothal
Urinary Tract Anti-infective Agents
The drugs which are used to treat or prevent infections of the urinary tract are called urinary tract anti-infective agents.
Ofloxacin
Ofloxacin is a synthetic fluoroquinolone antibiotic.
Chemical Name: 9-Fluoro-2,3-dihydro-3-methyl-104(4-methyl-1-piperazin-yl)-7- xo-7H-pyrido[1, 2, 3-de]-1,4,-benzoxazine-6-carboxylic acid.
Properties:
- It occurs as a pale yellow or bright yellow, crystalline powder.
- It is soluble in glacial acetic acid.
- It is slightly soluble in water, dichloromethane and methanol.
Stability and Storage: It should be stored at room temperature and should be kept away from light and moisture.
Uses:
- It is useful in the treatment of genitourinary, respiratory, gastrointestinal infections.
- It is used in the treatment of bronchitis and pneumonia.
Pharmaceutical Formulations:
- Ofloxacin tablets IP
- Ofloxacin oral suspension IP
- Ofloxacin ophthalmic solution IP
- Ofloxacin infusion IP
Brand Names:
- Oflox
- Exocin
- Zenflox
- Zanocin
- Tarivid
Antiarrhythmic Drugs
Antiarrhythmics are medications that prevent and treat heart rhythm that is too fast or irregular, also known as arrhythmias. Arrhythmia involves a problem with your heart’s electrical system. Your heart may beat too quickly, too slowly, or erratically.
Procainamide Hydrochloride
Chemical Name: 2-(diethylamino)ethyl 4-aminobenzoate
Uses:
- It is mainly used for infiltration anesthesia, peripheral nerve block, and spinal block.
Stability and storage conditions:
- It should be kept in a cool, dry place and stored at room temperature. Direct sunlight is prohibited.
Types of formulations:
- Injection
- Tablet
Popular brand names:
- Procanbid
- Pronestyl
Antianginal Drugs
Definition of ‘antianginal’: Antianginal is any drug that reduces the consumption of oxygen in the myocardium (the muscular tissue of the heart) or increases oxygen supply to the myocardium to prevent the symptoms of angina.
Antidepressants
Antidepressants are a class of medications used to treat depression and other mental health conditions.
Examples:
Imipramine Hydrochloride
Chemical Name: 3-(10,11-dihydro-5H-dibenzo[b,f]azepin-5-yl)-N,N-dimethylpropan-1-amine
Uses: Imipramine is a medication used in the treatment of depression and anxiety.
Stability and Storage Conditions: It should be kept in a cool, dry place and stored at room temperature. Direct sunlight is prohibited.
Type of Formulation:
- Tablet
- Capsule
- Oral suspension
Brand Name: Tofranil
Fluoxetine
Chemical Name: N-methyl-3-phenyl-3-[4-(trifluoromethyl)phenoxy]propan-1-amine.
Uses: Fluoxetine is used to treat depression, obsessive-compulsive disorder (OCD), bulimia nervosa, premenstrual dysphoric disorder (PMDD).
Stability and Storage Conditions: It should be kept in a cool, dry place and stored at room temperature. Direct sunlight is prohibited.
Type of Formulation:
- Tablet
- Capsule
- Oral suspension
Brand Name: Prozac
Anticonvulsants
Anticonvulsants, also known as antiepileptic drugs (AEDs) or antiseizure drugs, are medications used to prevent or control seizures. They work by affecting the electrical activity in the brain.
Phenytoin
Chemical Name: Sodium 5,5-diphenyl-2, 4-imidazolidinedione
Uses:
- Phenytoin is a medication used in the management and treatment of epilepsy, generalized tonic-clonic seizures, complex partial seizures, and status epilepticus.
Stability and Storage Conditions: It should be stored in the tightly closed or sealed container.
Types of Formulations:
- Tablet
- Capsule
- Oral suspension
- Injectable solution
Brand Name:
- Epanutin
- Epanutin Infatabs
Cholinergic Drugs
Any drug that mimics the action and nature of acetylcholine or butrylcholine can be called cholinergic.
Acetylcholine
Acetylcholine is the neurotransmitter at neuromuscular junctions, at synapses in the ganglia of the visceral motor system, and at a variety of sites within the central nervous system.
Chemical Name: 2-Acetoxy-N,N,N-trimethylethanaminium
Anti-inflammatory Drugs
Anti-inflammatory agents are medications that reduce inflammation.
Diclofenac
Chemical Name: [2-(2,6-Dichloroanilino)phenyl]acetic acid.
Chemical structure:
Uses:
- Diclofenac is a medicine that reduces swelling (inflammation) and pain.
- It’s used to treat aches and pains, as well as problems with joints, muscles and bones.
Stability and storage conditions: It should be kept in a cool, dry place and stored at room temperature. Direct sunlight is prohibited.
Types of formulations: Tablets
Popular brand names:
- Zipsor
- Zorvolex
Types of Errors
There are three types of errors that are classified based on the source they arise from. They are:
- Gross Errors
- Random Errors
- Systematic Errors
Gross Errors
This category basically takes into account human oversight and other mistakes while reading, recording, and readings. The most common human error in measurement falls under this category of measurement errors.
Random Errors
The random errors are those errors, which occur irregularly and hence are random. These can arise due to random and unpredictable fluctuations in experimental conditions.
Systematic Errors
Systematic errors can be better understood if we divide them into subgroups. They are:
- Environmental Errors
- Observational Errors
- Instrumental Errors
Environmental Errors
This type of error arises in the measurement due to the effect of the external conditions on the measurement. The external condition includes temperature, pressure, and humidity and can also include an external magnetic field.
Limit Test of Chloride
This test is carried out for identifying the chloride ions present in a standard solution.
Principle: The limit test for chloride is based on a reaction that occurs between silver nitrate and soluble chloride which is insoluble in dilute nitric acid. The test solution appears turbid due to the formation of silver chloride in the presence of dilute nitric acid.
Procedure: In this limit test, a standard solution and test solution are prepared and then the appearance of these two solutions is compared.
Test solution: 1.0 gm of sample is accurately weighed and transferred to a Nessler cylinder, dissolved in 10 ml distilled water. 1 ml of nitric acid is added to this solution and the volume is made up to 50 ml with distilled water. 1 ml of silver nitrate is added to the solution, stirring for 5 min after which turbidity develops.
Specified substance (1gm) + 10 ml of water + 1 ml of nitric acid + 1 ml of silver nitrate = turbidity
Standard solution: 1 ml of 0.01 M HCl is mixed with 1 ml of nitric acid in Nessler cylinder B and the volume is made up to 50 ml with distilled water. 1 ml of silver nitrate solution is added, which produces turbidity after 5 min.
The sample passes the limit test if it is less turbid than the standard solution.
Neutralization Reaction
A reaction in which an acid reacts with a base to produce a salt and a neutralized base is known as a neutralization reaction.
Example: Hydrochloric acid reacts with sodium hydroxide to form sodium chloride & water
HCl + NaOH = H2O + NaCl
Neutralization Curve: It is obtained when pH is plotted against the percentage of acid neutralization or the number of milliliters of alkali added.
Complexometric Titration
Chelatometry is a form of volumetric analysis in which the formation of a colored complex is used to indicate the endpoint of a titration.
Volumetric and Gravimetric Analysis
The quantitative analytical method widely used is volumetric analysis. It is defined as the method involved in the measurement of the volume of a solution whose concentration is known. This method is also applied to determine the concentration of analyte. Volumetric analysis or titration is defined as the measurement of the volume of a second substance which combines with the first known concentration.
Procedure for Volumetric Analysis
The solution that needs to be analyzed should have a specific weight in the sample of +/- 0.0001g of the material. It is important to choose the right kind of material which is to be analyzed to obtain accurate results. Preference should be given to a substance that reacts rapidly and completely to produce a complete solution. The titration should be continued until the reaction is completed and the amount of reactant added should be exactly the amount required. A weighed amount of reagent should be taken and dissolved into a solution if the reagent or reactant is to be made into a standard solution so that it is in a definitive volume within a volumetric flask.
Non-aqueous Titration
– Non aqueous titration is the most common titration procedure used in pharmacopoeial assays and serves a double purpose, as it is suitable for the titration of weak acids and weak bases and provides a solvent in which organic compounds are soluble