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Right choice is (a) An intermediate CONCENTRATION EXISTS at the interface

Easy explanation: An intermediate layer exist at the interface of the solid and liquid layers. This intermediate layer holds and intermediate concentration at the interface which results is solvation mechanism. The THEORY does not TALK about any turbulence, or presence of solutes.

Right answer is (d) PASSIVE diffusion

The EXPLANATION: Passive diffusion is also known as non-ionic diffusion. It is the major PROCESS through which 90% of the drugs get absorbed. The driving force for passive diffusion is the CONCENTRATION gradient and ELECTROCHEMICAL gradient.

Correct option is (d) A SALT solution of the drug

The EXPLANATION is: Vehicle is the solvent system for a liquid oral drug. There are 3 types of solvent drug, aqueous vehicle CONSISTING of water, syrup, etc. Non-aqueous water-miscible vehicles consisting of propylene GLYCOL, glycerol, sorbitol, etc. Nonaqueous water immiscible vehicles consisting of vegetable oils.

The CORRECT choice is (c) LARGE LIPOPHILIC GROUP

Easiest explanation: Ionised drugs if ATTACHED with a large lipophilic group in their structure. This helps them in getting absorbed passively e.g. morphine derivatives.

Correct answer is (a) PARACETAMOL

Easiest explanation: Paracetamol is a drug name. It is the active ingredient. EXCIPIENTS are all the other additional materials that HELP in drug formulation e.g. BINDERS, lubricants, DISINTEGRANTS, buffer, etc.

Correct choice is (a) ABSOLUTE surface AREA

To explain: Particle size and surface area of a solid DRUG are inversely related to each other. Absolute surface area is the total area of the solid surface of any particle and an effective surface area is the area of the solid surface exposed to the DISSOLUTION medium. Smaller the drug particle greater the surface area.

The correct option is (a) True

Easy explanation: Factors that are of in vivo IMPORTANCE, those which can affect the drug DISSOLUTION and absorption into the CELL MEMBRANE can be DIVIDED into 2 classes. One is the physicochemical properties of the drug and the dosage form factors.

Right CHOICE is (a) Promote cohesive compacts

Easy explanation: Binders and granulating agents are used to HOLD powders together to form compact tablets. They HELP in the formation of granules and promote cohesive compacts for COMPRESSIBLE materials. It ensures that the tablet remains INTACT after compression.

Right option is (a) True

For EXPLANATION: Disintegration of a tablet is directly proportional to the AMOUNT of binder present and the compression force i.e. the hardness of the tablet. A HARD tablet with a large amount of binder has a long DT.

The correct CHOICE is (C) CAPSULES and Tablets

Explanation: Disintegration time is of importance in the case of solid dosage forms like tablets and capsules. Disintegration time is the time TAKEN by the CAPSULE to disintegrate into smaller particles.

Right answer is (d) INCREASED ulcerogenic TENDENCY

The explanation: Including enhanced bioavailability, buffered aspirin TABLETS have more two ADVANTAGES that are, reduction of the gastric IRRITATION and ulcerogenic tendency of the drug. And second is the stability is increased by in-situ salt formation.

The CORRECT option is (b) False

For explanation I would say: The size of the counterion influences the SOLUBILITY of the salt forms. Smaller the size of the counterion greater the solubility of the salt. If the counter ion has a larger size or POOR ionic strength, the solubility DECREASES to a large extent.

Correct option is (b) False

To explain I would SAY: Absolute SURFACE area is not PROPORTIONAL to the Dissolution RATE. Effective surface area is proportional to the dissolution rate. Absolute surface area is the total area of the solid surface of any particle and an effective surface area is the area of the solid surface exposed to the dissolution medium. Effective surface area is the area of the solid surface exposed to the dissolution medium.

Right OPTION is (b) 1%

For explanation I WOULD say: Experiments have shown that a drug should have a minimum aqueous SOLUBILITY of 1% to avoid BIOAVAILABILITY PROBLEMS. Lesser than that it becomes a very serious issue for the drug to dissolve and give the proper effect.

Right choice is (B) Diffusion layer MODEL

The explanation is: Diffusion layer model states that solution of a SOLID form a thin film or layer at the solid-liquid interface which is called as the stagnant film or diffusion layer which GETS saturated with the drug. This step is RAPID.

Right CHOICE is (a) Carrier-mediated TRANSPORT

For explanation: Facilitated diffusion is a carrier-mediated transport which OPERATES down the concentration gradient. It is FASTER than passive diffusion because of the involvement of Carriers. The DRIVING force is the concentration gradient.

The correct ANSWER is (c) Acacia

For explanation: CMC and MC are examples of semisynthetic GUMS. Acacia is an example of a VEGETABLE drug that is ORGANIC. CARBOWAXES is an example of a soluble lubricants.

The correct OPTION is (B) Carbowaxes

To elaborate: PVP is a binding agent. Carbowaxes is a soluble lubricant. CMC is an EXAMPLE of semisynthetic GUMS. And TETRACYCLINE is diluent.

Right choice is (b) Unionized FORM mostly

The best I can explain: DRUGS that are moderately weak bases with pKa 5-11 will get ionized at gastric pH, stay unionized at INTESTINAL pH and get ABSORBED through the intestinal wall. Thus, heroin being a weak base will stay at unionized condition in the intestinal pH. It will not form any aggregate.

Right option is (b) False

For EXPLANATION: Greater the SURFACE area greater is the DISSOLUTION. Thus micronization of the drug is PREFERRED. Dissolution can be increased by micronization.

The CORRECT ANSWER is (a) ENDOCYTOSIS

The best EXPLANATION: Endocytosis is the absorption method which includes engulfing of extracellular MATERIALS within a segment of the cell membrane to form a saccule or vesicle which will be then pinched off intracellularly.

Correct ANSWER is (c) Hydrophobic core

Easiest explanation: Hydrophobic core don’t bind to any polar compound being hydrophobic, THUS it doesn’t allow polar compounds to PASS through the MEMBRANES EASILY. Heads of phospholipid bi-layer in cell membrane are always polar and tails are non-polar in nature.

The correct option is (b) POLAR head

To elaborate: Proteins are always BONDED to the polar head PART of the cell MEMBRANE, which is usually hydrophilic in nature. It is known that the heads are always polar and the tails are nonpolar, i.e hydrophobic in nature.

Correct choice is (d) Dissolution rate

Explanation: Some of the deviations of the pH-partition hypothesis are the presence of virtual MEMBRANE, absorption of the ionized drug, the influence of GI surface AREA and residence TIME, Presence of AQUEOUS unstirred diffusion LAYER.

The correct choice is (a) Cromolyn

To ELABORATE: Cromolyn pKa is 2.5. Rest all the other drugs are bases of Pka range 5-11.These are morphine analogues. Such drugs are BETTER absorbed from relatively ALKALINE conditions of the intestine where these molecules LARGELY exist in unionized form.

Right answer is (a) –ve log of H+ concentration

To EXPLAIN I WOULD say: pH is a scale used to measure how much acidic or BASIC a solution is. PH is logarithmic and negative of the 10-base logarithm of the molar concentration of the hydrogen IONS present.

Right choice is (d) Extreme reduction in the size brings the hydrophobic amino acids to the surface

The explanation: In the case of hydrophobic drugs, MICRONIZATION results in a decrease in EFFECTIVE surface area and thus fall is dissolution rate. Three reasons are, Hydrophobic surface of the drugs ADSORBS onto their surface which inhibits their WETTABILITY, the particles reaggregate to form larger particles due to their high surface FREE energy, extreme reduction in the particle size impart surface charges that may prevent wetting.

Correct OPTION is (d) Molecules greater than 400 Dalton

Easy explanation: Pore transport is important for the absorption of low MOLECULAR weight and size molecules. Water-soluble drugs can also EASILY pass through the AQUEOUS filled spaces or pores in the cell membrane. LINEAR molecules of size up to 400 Dalton can be absorbed.

Correct choice is (b) False

Best explanation: Compression FORCE while the making of tablet and PACKING density (capsule packing) can INHIBIT or promote dissolution. Capsules with fine particles and intense packing have poor drug release and dissolution due to a decrease in the pore size between the molecules. THUS giving them poor penetrability into the GI fluids.

The correct answer is (b) False

For explanation I would SAY: Agglomerative phase of communication is a recent process which involves GRINDING the drug in a BALL mill for a long time to affect spontaneous agglomeration. The tablets so PRODUCED were stronger and showed RAPID dissolution in comparison to tablets made by other methods.

The correct answer is (b) False

For explanation: Particle SIZE and SURFACE AREA of a solid DRUG are inversely related to each other. Smaller the drug particle greater the surface area. Larger the area is higher the dissolution rate.

The correct answer is (B) Semipermeable

To ELABORATE: A cell MEMBRANE is always semi permeable that is it permits rapid and limited PASSAGE of some of the compounds and RESTRICTS other compounds.

The correct answer is (B) False

The BEST EXPLANATION: The head is PHOSPHATE containing POLAR or hydrophilic. The tail is non polar carbon tail or hydrophobic. The phospholipid bilayer of a cell membrane is composed of such lipids with polar head and non-polar tail.