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Right answer is (B) Scatchard plot

Easiest EXPLANATION: The plot between r/d v/s r is known as Scatchard plot. This plot is a STRAIGHT line. The SLOPE of the line –Ka, Y INTERCEPT is NKa and X intercept is N.

The correct answer is (d) Amount of drug in the body

To elaborate: The relationship between tissue-drug binding and apparent VOLUME of distribution can be established as VD = amount of drug in the body (X)/ PLASMA drug concentration (C).

Correct ANSWER is (a) COMPETITION between drugs for the BINDING site

Explanation: Physicochemical interaction is not a drug interaction factor. Competition between the drug and the binding site and competition between drug and other normal body constituents, allosteric changes in PROTEIN molecule all these factors are RELATED to drug interaction with the protein. Age is a patient-related factor.

Right choice is (a) Steroidal drugs

The best I can explain: Several plasma GLOBULINS were identified and NAMED as Α1, Α2, Β1, Β2, γ globulins. Α1 globulin bind to steroidal drugs. For example cortisone, PREDNISONE, thyroxine, cyanocobalamin. It is ALSO KNOWN as transcortin.

The CORRECT answer is (d) Lipophilic drug

To explain I would say: Lipophilic drugs such as that of thiopental and pesticides such as DDT accumulate in adipose tissue. Halogenated HYDROCARBON and PARACETAMOL bind irreversibly to the liver tissues RESULTING in hepatotoxicity. Tetracycline tends to bind to bones and teeth.

Right answer is (d) Chloroquinine

For explanation I would say: Chloroquine and phenothiazines accumulate in skin by interacting with melanin.Since our RETINAL pigment of eye also has melanin, BINDING of chloroquine and phenothiazines to it is RESPONSIBLE for retinopathy.

Right choice is (d) CAROTENOIDS

The EXPLANATION: Several PLASMA globulins were identified and named as Α1, Α2, Β1, Β2, γ globulins. Β2 globulin BINDS to carotenoids.

Correct option is (b) False

Easy EXPLANATION: Alpha 1 ACID GLYCOPROTEIN is also called as orsomucoid. It has a molecular weight of 44,000 and a plasma concentration of range 0.04-0.1%. It BINDS basic drugs like imipramine, lidocaine, quinidine, etc.

Right option is (a) Cationic drug

The EXPLANATION is: ANIONIC or acidic drugs bind to HSA easily. Cationic or basic drugs having negative charge can bind easily to alpha 1 acid glycoprotein, for example, IMIPRAMINE and alprenolol. Neutral and unionized drugs bind to lipoproteins. Lipophilic drugs localize more into adipose TISSUE.

The correct ANSWER is (c) Lipophilic drug

To elaborate: Anionic or acidic drugs bind to HSA easily. Cationic or basic drugs bind easily to alpha 1 acid glycoprotein. Neutral and unionized drugs bind to lipoproteins. Lipophilic drugs localize more into ADIPOSE tissue. SINCE lipophilic drugs are lipid loving they can easily get DEPOSITED on the adipose tissue.

The correct answer is (d) WARFARIN and azapropazone binding SITE

Easiest explanation: In the structure of HSA there 4 main binding sites for drugs. The site I am CALLED as the warfarin and azapropazone binding site. In this REGION, a large number of drugs can bind. For example several NSAIDs, phenytoin, sodium valproate, bilirubin.

Right ANSWER is (C) Double reciprocal plot

The explanation: Double reciprocal plot is also KNOWN as Lineweaver Burk plot. This plot of 1/r versus 1/D yields a STRAIGHT LINE with slope 1/NKa and Y-intercept 1/N.

The correct option is (d) Inter subject variation

The explanation is: Competition between the drug and the BINDING site, competition between drugs and normal body constituents, ALLOSTERIC changes in protein molecule these factors are related to drug interactions. Inter subject variation is a patient-related FACTOR.

Right answer is (b) Tetracycline

Explanation: Tetracycline, this DRUG tends to bind to bones and teeth. Administration of this antibiotic to infants or CHILDREN during odontogenesis results in permanent BROWN YELLOW colour discoloration of teeth.

The correct choice is (a) True

The explanation: PENICILLIN has a short plasma half-life. Though it can rigidly bind to the plasma still it has short ELIMINATION half live. This is because equilibration occurs between the free and the bound PROTEIN and the free drug is equally rapidly excreted by active secretion in renal TUBULES.

The correct OPTION is (d) Number of binding SITES on the binding AGENT

For explanation: There are many factors affecting protein-DRUG binding. The factors related to the drug, are PHYSICOCHEMICAL characteristics of a drug, concentration of the drug in the body, affinity of the drug for binding. A number of binding sites on the binding agent are related to the protein and other binding components.

The correct answer is (b) BASIC drugs LIKE IMIPRAMINE

To explain: Imipramine is a basic drug. Basic drug like imipramine, CHLORPROMAZINE and anti-histamines accumulate in LUNGS.

Correct choice is (a) True

Easy EXPLANATION: A displacement of 1% and 99% bound drug RESULTS in doubling of the FREE drug concentration i.e. a 100% rise. For a drug which is bound to 99% and a displacement of 1% results in only a 10% rise in FREED rug concentration which may be insignificant clinically.

The correct OPTION is (c) Imipramine

For explanation: The red blood cell comprises of 3 components each can bind to different KIND of drugs. HAEMOGLOBIN, Carbonic ANHYDRASE, and cell membrane. The cell membrane is reported to bind with CHLORPROMAZINE and imipramine.

Right choice is (a) Globulin

To explain I would SAY: The human SERUM ALBUMIN is the most abundant PROTEIN in the human body. It has a large DRUG binding capacity. It can bind to several compounds with a variety of structure. There are 4 different drugs binding site in HSA. It is of globulin family.

The CORRECT answer is (a) True

For explanation: The concentration of drug that binds to HSA do not have much influence on HA, since any concentration of drug in LESS than the concentration of HSA. The therapeutic concentration of lidocaine can saturate AAG with which it binds as the concentration of AAG is much less in comparison to that of HSA in blood.

Right option is (c) Diazepam binding site

The best explanation: In the structure of HSA there 4 main binding sites for drugs. The 2nd drug binding site is Diazepam binding site. Drugs that binds to this site INCLUDES BENZODIAZEPINES, medium chain fatty ACIDS, cloxacillin, probenecid, tryptophan, KETOPROFEN, ibuprofen, etc.

The CORRECT choice is (c) Cu/C

To explain I would SAY: The fraction of unbound drug can be CALCULATED with the formula fu = Cu/C, where Cu is the CONCENTRATION of unbound drug and C is TOTAL plasma drug concentration and fu is the unbound drug.

Right CHOICE is (b) Anionic drug

To elaborate: Anionic or acidic drugs bind to HSA EASILY, for example, penicillin and sulphonamides. Cationic or BASIC drugs bind easily to alpha 1 acid glycoprotein, for example, imipramine and alprenolol. Neutral and unionized drugs bind to lipoproteins. Lipophilic drugs LOCALIZE more into adipose tissue.

Correct answer is (b) Digitoxin binding SITE

For explanation I would say: In the structure of HSA there 4 main binding sites for drugs. The 3RD drug binding site NAME is Digitoxin binding site.

The CORRECT CHOICE is (d) Fatty acids

Explanation: Lipoproteins are classified into 4 classes. The classes are CHYLOMICRONS, very low-density lipoproteins (VLDL), low-density lipoproteins (LDL), high-density lipoproteins (HDL).

The correct option is (a) DIRECT plot

For explanation I would say: The GRAPH which is got by potting r v/s D then we call it a direct plot. When all the binding sites are OCCUPIED by the drug, the protein is saturated and plateau is reached. At the plateau r=N.

The correct option is (a) Arsenicals

For explanation I would say: Arsenicals, chloroquine, PHENOTHIAZINES are reported to deposit in hair shaft. Tetracycline binds to BONES and teeths. Lipophilic DRUGS accumulate in adipose tissues. Epoxides of number of Halogenated hydrocarbon and paracetamol BIND irreversibly to the liver tissues resulting in hepatotoxicity.

The correct OPTION is (d) LIVER > KIDNEY > lung > muscle

Easiest EXPLANATION: Factors influencing localization of drugs are tissues lipophilicity, structure of drug, perfusion rate, pH differences etc. Drugs binding to the extracellular site has the order of binding in DECREASING order liver > kidney > lung > muscle.

Correct CHOICE is (a) Increases the volume of distribution of drugs and RESULTS in localization of DRUG at a specific SITE

For EXPLANATION: Tissue-drug binding is important in the distribution of drugs. This is because it increases the apparent volume of distribution of drugs in contrast to plasma protein which decreases it. Tissue-drug binding results in localization of the drug at a specific site in the body.

Right answer is (d) COVALENT bond

To explain: Covalent bonds are strong bonds. Drugs always bind through weak chemical bonds such as that of the hydrogen bond, hydrophobic bond, ionic bond, and van der Waal’s FORCES. These are reversible processes. Irreversible BONDING i.e. covalent bonding arises the issue of toxicity or carcinogenicity.