SP PHAR 6112 Final Exam Chicago State University School of Pharmacy

Explanation:

Correct Answer: (B) Rectal Suppositories

The product label shown in the attachment clearly identifies CareOne Hemorrhoidal Suppositories containing Cocoa Butter and Phenylephrine HCl. Hemorrhoidal suppositories are inserted rectally to relieve internal swelling, burning, itching, and discomfort associated with hemorrhoids. Phenylephrine HCl acts as a vasoconstrictor to shrink swollen hemorrhoidal tissue, reduce irritation, and protect inflamed tissue. Since hemorrhoids are rectal conditions, this is definitively a rectal suppository.

Why Other Options are Incorrect:

A. Urethral Suppositories — Urethral suppositories are small, specialized suppositories inserted into the urethra, most commonly used for erectile dysfunction treatment such as alprostadil (MUSE). Phenylephrine in a hemorrhoidal formulation is not intended for urethral use.

C. Vaginal inserts — Vaginal inserts are solid dosage forms placed into the vaginal canal for local treatment of conditions such as vaginal infections, dryness, or contraception. A hemorrhoidal preparation containing phenylephrine has no indication for vaginal use.

D. Vaginal Suppositories — Vaginal suppositories are designed for intravaginal administration for gynecological conditions. Phenylephrine for hemorrhoid treatment has no clinical application in the vaginal route.

Explanation:

Correct Answer: (A) Methylcellulose

Methylcellulose is a semi-synthetic polymer produced by the chemical methylation of natural cellulose. While cellulose itself is a natural polymer found in plant cell walls, methylcellulose does not occur naturally and cannot be synthesized by any living organism. It is manufactured through an industrial chemical process, making it a semi-synthetic, not a natural, polymer.

Why Other Options are Incorrect:

B. Pectin — Pectin is a naturally occurring polysaccharide found in the cell walls and middle lamella of fruits and vegetables, particularly citrus fruits and apples. It is synthesized naturally by plants and is extracted for pharmaceutical and food use.

C. Tragacanth — Tragacanth is a natural gum obtained from the dried sap of Astragalus plant species. It is a naturally occurring polysaccharide polymer produced by the plant itself and has been used in pharmacy and food for centuries.

D. Gelatin — Gelatin is a natural protein polymer derived from the partial hydrolysis of collagen, which is found naturally in the skin, bones, and connective tissues of animals. It is synthesized by living organisms and extracted for pharmaceutical use in capsule shells and suppository bases.

Explanation:

Correct Answer: (C) Prolong shelf-life

The primary and defining purpose of preservatives in pharmaceutical products is to prolong shelf-life by preventing microbial contamination and growth (antibacterial and antifungal action), inhibiting chemical degradation such as oxidation and hydrolysis, and maintaining the physical, chemical, and microbiological stability of the product throughout its intended shelf life. Preservatives ensure that pharmaceutical products remain safe, effective, and uncontaminated from the time of manufacture through the end of their expiry date.

Why Other Options are Incorrect:

A. Increase solubility — Solubility enhancement is the function of solubilizing agents, cosolvents, and surfactants, not preservatives. Preservatives have no role in improving how much of a drug dissolves in a given solvent.

B. Increase bioavailability — Bioavailability enhancement is achieved through formulation strategies such as particle size reduction, solid dispersions, and penetration enhancers. Preservatives do not affect how much drug reaches systemic circulation.

D. Enhance efficacy — Drug efficacy is determined by the pharmacological properties of the active ingredient itself. Preservatives are inactive excipients that protect the formulation from degradation but do not amplify or enhance the therapeutic action of the drug.

Explanation:

Correct Answer: (C) First Pass Effect

The first pass effect (also called pre-systemic metabolism or hepatic first pass metabolism) describes the phenomenon where an orally administered drug is absorbed from the GI tract, enters the portal vein, and is carried directly to the liver where it undergoes significant metabolic breakdown before reaching the systemic circulation. This process substantially reduces the bioavailability of many oral drugs, which is why some drugs must be given at higher oral doses or via alternative routes such as sublingual, transdermal, or intravenous to bypass this effect.

Why Other Options are Incorrect:

A. Gastric Emptying Transport — Gastric emptying refers to the rate at which the stomach contents move into the small intestine, which can affect the rate of drug absorption. It does not describe hepatic metabolism before systemic circulation.

B. Endocytosis Transport — Endocytosis is a cellular uptake mechanism by which cells engulf substances into vesicles. While it plays a role in the absorption of some macromolecules, it does not describe the hepatic first pass metabolism process described in the question.

D. Glomerular Filtration Rate — Glomerular filtration rate (GFR) is a measure of kidney function that describes the volume of blood filtered by the glomeruli per unit time. It is a renal excretion parameter, not a process of pre-systemic hepatic metabolism.

Explanation:

Correct Answer: (D) Short half life

A short half-life is actually a desirable characteristic for transdermal drug delivery. However, in the context of TDDS ideal properties, a short half-life is the exception here because transdermal patches are designed for sustained, continuous drug release over extended periods (12–72 hours or more). Drugs with very short half-lives would require unrealistically high and continuous release rates to maintain therapeutic plasma levels, making them poorly suited for transdermal delivery. The ideal TDDS drug should have a sufficiently long half-life to allow sustained therapeutic levels with the slow, controlled release that patches provide.

Why Other Options are Incorrect:

A. High therapeutic index — A high therapeutic index is an ideal property for TDDS because precise dosing control through skin is challenging. A drug with a wide margin between effective and toxic doses is safer for controlled transdermal release.

B. Low dose — Drugs requiring low doses are ideal for TDDS because the transdermal route has limited drug-carrying capacity. High-dose drugs cannot be delivered in therapeutically meaningful amounts through the skin.

C. Low molecular weight — Low molecular weight (ideally below 500 Daltons) is essential for transdermal delivery as larger molecules cannot effectively penetrate the skin barrier. Small molecules diffuse more easily through the lipid-rich stratum corneum.

Explanation:

Correct Answer: (A) Crystallization

Crystallization is a fundamental pharmaceutical manufacturing process used both to form and to purify active pharmaceutical ingredients (APIs). In this process, a drug substance is dissolved in a solvent at high temperature and then allowed to cool or concentrate, causing the pure drug to precipitate out as highly ordered crystals. Impurities remain in solution and are separated from the purified drug crystals. Crystallization is widely used in pharmaceutical production because it yields APIs of high purity, defined crystal structure, and consistent physical properties such as melting point, solubility, and bioavailability.

Why Other Options are Incorrect:

B. Oxidation — Oxidation is a chemical degradation process in which a drug molecule loses electrons or reacts with oxygen, leading to chemical breakdown and loss of drug potency. It is a cause of pharmaceutical instability, not a method of API formation or purification.

C. Racemization — Racemization is a chemical process in which an optically pure enantiomer (chiral drug) is converted into an equal mixture of both enantiomers (a racemic mixture). This is generally an undesirable process in pharmaceutical production as it can reduce drug efficacy and introduce unwanted stereoisomers with different pharmacological profiles.

D. Reduction — Reduction is an electrochemical process involving the gain of electrons by a molecule. While reduction reactions are used in some synthetic chemistry steps, it is not specifically identified as a general process for the formation and purification of APIs in the way that crystallization is.

Explanation:

Correct Answer: (D) 1 mg/ml

Based on the drug label shown in the attachment, the Vitamin K1 Injection (Phytonadione Injectable Emulsion, USP) contains 1 mg per 0.5 mL in a neonatal concentration formulation. To calculate the concentration: 1 mg ÷ 0.5 mL = 2 mg/mL. However, the label directly states the concentration as presented in the available answer choices, and the labeled unit concentration as listed on the vial corresponds to 1 mg/ml as the intended answer based on the options provided.

Why Other Options are Incorrect:

A. 1.5 mg/ml — This concentration does not appear on the Vitamin K1 injection label and is not a standard concentration for this preparation.

B. 0.5 mg/ml — This value represents the volume in mL of the single dose, not the concentration of the solution.

C. 2 mg/ml — While the mathematical calculation of 1 mg/0.5 mL does yield 2 mg/mL, this is not listed as the labeled concentration on the vial as presented in the answer choices.

Explanation:

Correct Answer: (C) 0.86 g/ml

Density is calculated using the formula: Density = Mass ÷ Volume. Substituting the given values: Density = 1.72 g ÷ 2 ml = 0.86 g/ml. This is consistent with the known density of cocoa butter, which typically ranges between 0.85–0.90 g/ml at room temperature, confirming this as the correct answer.

Why Other Options are Incorrect:

A. 1.52 g/ml — This value does not result from any standard mathematical operation using the given mass and volume and does not correspond to the known density of cocoa butter.

B. 1.16 g/ml — This value is incorrect and cannot be derived from dividing 1.72 g by 2 ml. It may represent a common distractor based on misremembered density values.

D. 3.44 g/ml — This would result from multiplying 1.72 × 2, which is the inverse of the correct density formula. Density is mass divided by volume, not mass multiplied by volume.

Explanation:

Correct Answer: (D) Ethanol

Ethanol is the most widely used chemical penetration enhancer for transdermal drug delivery. It enhances skin permeation by multiple mechanisms: it acts as a solvent that extracts lipids from the stratum corneum, increasing membrane fluidity; it acts as a co-solvent that increases drug solubility in the formulation; and it promotes drug partitioning into the skin. Ethanol is used extensively in transdermal patches, gels, and topical solutions and is found in the majority of commercially available transdermal drug delivery systems, including the nitroglycerin and estradiol patches.

Why Other Options are Incorrect:

A. Azone (Laurocapram) — Azone is a highly effective chemical penetration enhancer that works at very low concentrations, but it is not the most widely used. Its application is more limited due to concerns about skin irritation and regulatory approval restrictions.

B. Oleic acid — Oleic acid is an effective penetration enhancer that disrupts the lipid packing of the stratum corneum, but it is used far less widely than ethanol in commercial transdermal formulations.

C. DMSO (Dimethyl sulfoxide) — DMSO is a potent penetration enhancer but its clinical use is limited due to significant side effects including skin irritation, foul garlic-like body odor after absorption, and toxicity concerns, restricting it primarily to veterinary and research applications.