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Right option is (a) DRUGS bound to PLASMA proteins

To explain: Drugs that are bound to plasma behave as macromolecules don’t GET filtered through the glomerulus. Unbound free drug which are less than 300 Dalton get filtered by the glomerulus.

The correct answer is (b) False

For explanation: COMPOUNDS with molecular weight below 300 Dalton will be filtered easily through the glomerulus. Drugs in the molecular weight range of 300-500 Dalton will be filtered through the bile and URINE both. Molecules of SIZE more than 500 Dalton will be filtered out through urine but to a lesser EXTENT.

Correct answer is (d) The cleaving of the carrier is also site-specific

To explain I would say: The LIMITATION of the prodrug designing is the formation of unexpected metabolite, the inert carrier can be cleaved off forming a toxic molecule, and prodrug might CONSUME vital nutrients. If the carrier cleavage is site specific it is an advantage.

Right choice is (c) Drug filtered as well as actively secreted

The explanation: The DRUGS which are secreted or reabsorbed, the rate increases with an increase in PLASMA concentration to a point where SATURATION occurs. Drugs that are actively secreted, the rate of excretion increases with increase in plasma concentration up to a saturation level. A drug that will not be bound to the plasma proteins and excreted by only FILTRATION will have linear relationship between the rate of excretion and plasma drug concentration.

Right answer is (B) Disintegration RATE

To elaborate: Important PHYSICOCHEMICAL factor that has effect on the renal excretion are molecular size, PKA of the drug, and lipid solubility. A small molecular sized compound can easily get filtered out by the glomerulus. Compounds of eight below 300 Dalton and WATER soluble, can get readily excreted by glomerulus. Disintegration rate does not affect the excretion, it will affect absorption.

Right answer is (a) True

Easiest explanation: A higher AMOUNT of URINE FLOW leads to less reabsorption. A lower amount of urine flow leads to more reabsorption. Polar drugs whose excretion is independent of urine pH and are not reabsorbed are unaffected by urine flow rate. Those drugs whose reabsorption is pH sensitive is DEPENDENT on the flow rate of urine.

Correct choice is (d) Heart rate

To ELABORATE: Heart rate does not DIRECTLY influence the pulmonary excretion. Though it might be a factor influence is very less. The other three factors are directly RELATED to the LUNGS and the rate of absorption of the drug from the lungs and out of the lungs BACK to alveoli.

Correct option is (c) Site-specific drug delivery

The explanation: Pharmaceutical applications are those where the UNDESIRABLE properties and the physicochemical problems can be SOLVED. These are, for example, improving taste, ODOUR, change of PHYSICAL form, reduction in GI irritation, reduction of pain on INJECTION. Pharmacokinetic applications are such as enhancement of bioavailability, prevention of presystemic metabolism, prolongation of the duration of action, reduction of toxicity, etc.

The correct option is (c) FORM esters and ETHER products

The best explanation: Providing orally will have to pass through the hepatic 1st pass. Forming ETHERS and esters can prevent extensive first-pass hepatic metabolism. Propanol has the HIGH hepatic first pass, it is pro-drug hemisuccinate is resistant to esterases of the liver.

The CORRECT option is (b) FAVOURS passive DIFFUSION

To elaborate: Lipophilic drugs has high membrane-water partition coefficient thus it favours passive diffusion. These are more lipophilic, better absorbed and rapidly hydrolysed to the parent DRUG in BLOOD.

Correct choice is (B) False

The EXPLANATION: Drugs can cause IRRITATION and damage to the gastric mucosa, it can increase stimulation of ACID SECRETION or cause damage to the mucosal layer. NSAIDs cause serious harm to our mucosal layer. They are one of the main causing agents of ulcer.

The correct answer is (c) Benorylate prodrug for NSAIDs and paracetamol

For explanation: Mutual prodrug is pro-drugs COMPRISING of 2 pharmacologically active AGENTS COUPLED together to form a single product. Thus, benorylate prodrug for NSAIDs and paracetamol is an EXAMPLE of mutual prodrug.

Correct choice is (b) RATE of filtration + rate of SECRETION – Rate of absorption

Explanation: The rate of excretion through the kidneys is given by Rate of filtration + rate of secretion – Rate of absorption. Absorption is the reabsorption of the drug particles BACK to the SYSTEM thus it gets minus from the filtrated amount and secreted amount.

Right choice is (b) Biliary excretion rate/ plasma drug concentration

For explanation: The ability of the liver to EXCRETE drug into the bile is expressed as bile clearance. The equation for bile clearance is biliary excretion rate/ plasma drug concentration. Since biliary excretion can also be written as bile FLOW * biliary drug concentration. The other equation for bile clearance is bile flow * biliary drug concentration/ plasma drug concentration.

Right choice is (c) Less DISTRIBUTION TIME

To explain I would say: Less distribution time is an advantage for the drug. The disadvantages are may lead to toxic effects to other non-TARGET TISSUES, may get diluted due to distribution and smaller fraction reach the target tissue, May not be able to penetrate the target tissue, higher distribution time.

The CORRECT answer is (d) Hydrolysed easily

The explanation is: Carbenicillin, broad-spectrum penicillin, gets hydrolyzed very easily. Thus if given orally it will be a REACTION with ACID in the stomach. Thus these are MADE into ester prodrugs which are stable at gastric pH and above 7.

Correct answer is (C) Passive diffusion

Explanation: Passive excretion of drugs occurs through the SKIN. In the case of excretion through the skin, drugs follow pH PARTITION hypothesis. Free, unionized, LIPOPHILIC drugs can passively be diffused into the SWEAT.

Right ANSWER is (b) False

Explanation: A soft drug is a biologically active compound which GETS bio-transformed rapidly in vivo and starts the pharmacological activity. A hard drug is one which is RESISTANT to biotransformation and THEREFORE has a LONG half-life.

Right option is (a) True

To explain I would say: In the creation of prodrug, INSUFFICIENCIES of a DRUG are corrected through chemical conversion or multiple chemical CHANGES. Due to these chemical conversions which are done to make the drug to BECOME an acceptable form prodrug designing is also known as chemical FORMULATION.

The CORRECT choice is (a) Rate of urinary excretion/plasma drug concentration

To elaborate: Renal CLEARANCE is defined as the VOLUME of plasma or blood which is completely cleared of the unchanged drug by the kidney per unit TIME. It is expressed as an equation that is the Rate of urinary excretion/plasma drug concentration. It is the sum of the rate of glomerular filtration and rate of secretion minus the rate of absorption to the plasma drug concentration.

Right answer is (d) Reducing drug solubility in SALIVA and lower affinity for taste receptors

Explanation: Reason for poor patient compliance particularly for children is very important. For children, bitterness, acidity, causticity, and even the COLOR MATTERS a lot. Two APPROACHES for changing or DECREASING bad taste are, reducing drug solubility in saliva and lower affinity of the drug for taste receptors, thus patients cannot taste the drug.

The correct answer is (c) Improvement of odour

Explanation: Pharmaceutical applications are those where the undesirable properties and the physicochemical problems associated with drug formulations can be solved. These are, for example, improving taste, odour, CHANGE of physical form, REDUCTION in GI IRRITATION, reduction of PAIN on injection.

Correct option is (d) The active drug is converted to its inert FORM chemically

Explanation: Bioprecursors/ METABOLIC precursors are obtained after chemical modification of the active drug. They are made to form inert molecules and thus they do not need a carrier. This MOIETY has the same lipophilicity as the PARENT drug.

The correct choice is (a) 104g/min

The best I can explain: Clearance is expressed through the equation of elimination RATE/PLASMA drug CONCENTRATION. So, for the elimination rate, the equation BECOMES clearance * plasma drug concentration. Thus the answer becomes 130*0.8= 104 g/min.

Correct CHOICE is (a) True

The best I can explain: The clearance decreases when a DRUG has a large VOLUME of distribution. A drug with large Vd is POORLY excreted in URINE. Blood restricted to blood compartments have higher excretion rates.

Correct ANSWER is (d) 1.3ml/sec

The explanation is: The rate of EXCRETION through the KIDNEYS is given by the Rate of filtration + rate of SECRETION – Rate of absorption. Thus, for the rate of filtration, the equation becomes Rate of excretion – the rate of secretion + rate of absorption.

The correct option is (a) 0.421

To EXPLAIN: Renal clearance RATIO is the ratio between renal clearance of the drug and the renal clearance VALUE compound which gets cleared by glomerular FILTRATION only. Thus, the answer is 40/95=0.421.

Correct choice is (d) 72.8 g/ml

Explanation: The FRACTION of DRUG bound to plasma proteins can be calculated by the equation fu = Cu/C. Here Fu is fraction of unbound drug and Cu is the concentration of unbound drug in plasma and C is the total plasma concentration of the drug. For the CALCULATION of unbound drug concentration, the equation will be unbound drug fraction * total plasma concentration. Thus the answer will be 0.52*140 = 72.8 g/ml.

The correct option is (a) Covalent bond

Best EXPLANATION: This TYPE of prodrug where the active ingredient and inert drug is bonded by the covalent bond comes under carrier-linked prodrug. They are generally esters or amide. These drugs and modified their LIPOPHILICITY to a great EXTENT because of being attached to a carrier. The active drug is RELEASED by hydrolytic cleavage. The hydrolytic cleavage can be chemical or enzymatic.

Correct option is (d) SUM of renal and non-renal clearances

Easiest EXPLANATION: The sum of INDIVIDUAL clearances by all eliminating organs is called total body clearance or total systemic clearance. It is expressed as the sum of renal and non-renal clearance. This term is APPLIED to all organs involved in drug ELIMINATION.

Right choice is (c) Creatinine

To elaborate: GFR is determined by AGENT which is excreted exclusively by glomerular filtration and is neither secreted nor reabsorbed in the tubules. The excretion RATE of such compounds is 120-130 ml/min. The compounds USED are creatinine, INSULIN, mannitol, sodium thiosulfate.

Correct choice is (C) Blood PH

To ELABORATE: The factors that AFFECT the urinary excretion are, physicochemical properties of the drug, plasma concentration of the drug, Distribution and binding characteristics of the drug, urine pH, and blood flow to the kidneys, disease state, drug interactions, and other biological factors. The blood pH don’t directly affect the renal clearance.

The correct option is (C) Renal CLEARANCE of drug/ renal clearance of creatinine

For explanation: It is the clearance ratio of a drug with that of the clearance value compound which gets CLEARED by glomerular filtration only. Thus, the renal clearance ratio is EXPRESSED by clearance of drug/clearance of creatinine.

Correct choice is (a) 6.4-7.6

To explain I would say: The PH of the milk varies 6.4 – 7.6. The MEAN pH is 7. Unionized and lipid soluble drugs can easily diffuse into the mammary ALVEOLAR cells passively.

Correct option is (b) Gaseous

The best explanation: Gaseous substances and volatile substances find their excretion way through the lungs into the expired air. These substances easily get absorbed through the TISSUE of the lungs by simple DIFFUSION. Such as general anesthetics are absorbed through the lungs. Intact gaseous DRUGS are excreted but not the METABOLITES.

The correct option is (d) Drugs with bile/plasma concentration ratio above 1000

The EXPLANATION: The categories are divided into Group A, Group B, Group C. Group A has drugs with bile/plasma concentration ratio approximately 1 e.g. sodium. Group B has drugs with bile/plasma concentration ratio between 10 -1000 e.g. CREATININE. Group C has drugs with bile/plasma concentration ratio LESS than 1 e.g. sucrose.