Unorganized drugs – dried latex MCQs With Answer

Unorganized drugs – dried latex MCQs With Answer

This concise introduction covers dried latex as an important group of unorganized drugs in pharmacognosy for B.Pharm students. It explains origins, characteristic constituents (alkaloids, polyisoprene, resins, proteins), common examples (opium, natural rubber, gutta-percha, chicle), key identification features, pharmaceutical processing, storage and common uses in medicines and dentistry. Emphasis is on analytical tests, isolation of active principles, physicochemical properties, adulteration and pharmacological relevance. The content is practical and exam-oriented to strengthen both theoretical understanding and application in lab practice. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What is meant by ‘dried latex’ in the context of unorganized drugs?

• A solidified plant exudate that was originally a milky aqueous suspension containing resins, proteins and rubber particles
• A crystalline secreted sap composed only of sugars and starch
• A woody tissue removed from stems and bark
• A fermented plant juice used for beverages

Correct Answer: A solidified plant exudate that was originally a milky aqueous suspension containing resins, proteins and rubber particles

Q2. Which of the following is a classic example of dried latex used in pharmacognosy?

• Digitalis leaves
• Opium from Papaver somniferum
• Clove bud oil
• Cinchona bark

Correct Answer: Opium from Papaver somniferum

Q3. The primary polymer responsible for the elastic properties of natural rubber is:

• Cellulose
• Cis-1,4-polyisoprene
• Starch
• Gutta-percha (trans-1,4-polyisoprene)

Correct Answer: Cis-1,4-polyisoprene

Q4. Gutta-percha differs from natural rubber primarily because it is composed mainly of:

• Cis-1,4-polyisoprene
• Trans-1,4-polyisoprene
• Polyethylene
• Cellulose acetate

Correct Answer: Trans-1,4-polyisoprene

Q5. Which dried latex is commonly used for root canal filling in dentistry?

• Natural rubber
• Opium
• Gutta-percha
• Chicle

Correct Answer: Gutta-percha

Q6. The major pharmacologically active alkaloid in opium that produces strong analgesic effects is:

• Quinine
• Morphine
• Atropine
• Caffeine

Correct Answer: Morphine

Q7. Which constituent class is typically abundant in dried opium?

• Alkaloids (e.g., morphine, codeine)
• Essential fatty acids
• Polysaccharide gums only
• Tannins exclusively

Correct Answer: Alkaloids (e.g., morphine, codeine)

Q8. A practical method to collect plant latex for production of dried latex is:

• Steaming the roots and collecting steam condensate
• Incising the bark or pods and allowing the exudate to coagulate on exposure to air
• Pressing fresh leaves to obtain juice
• Fermenting flower petals in water

Correct Answer: Incising the bark or pods and allowing the exudate to coagulate on exposure to air

Q9. Which plant is the principal commercial source of natural rubber?

• Palaquium gutta
• Hevea brasiliensis
• Manilkara zapota
• Papaver somniferum

Correct Answer: Hevea brasiliensis

Q10. Chicle, a traditional chewing gum base, is obtained as dried latex from which plant?

• Manilkara zapota (sapodilla)
• Papaver somniferum
• Hevea brasiliensis
• Piper nigrum

Correct Answer: Manilkara zapota (sapodilla)

Q11. Which statement best contrasts latex and resin?

• Latex is an aqueous emulsion containing proteins and rubber particles; resin is a non-aqueous, viscous secretion of terpenoids and resin acids
• Resins are always water soluble while latex is insoluble in organic solvents
• Latex and resin are chemically identical in composition
• Latex is crystalline, whereas resin is gaseous

Correct Answer: Latex is an aqueous emulsion containing proteins and rubber particles; resin is a non-aqueous, viscous secretion of terpenoids and resin acids

Q12. Which analytical property helps to separate rubber particles from the aqueous serum during processing?

• Boiling under high pressure
• Coagulation by acids or mechanical means followed by washing
• Fermentation with yeast
• Extraction with hot water

Correct Answer: Coagulation by acids or mechanical means followed by washing

Q13. In pharmacognostic examination, alkaloids present in dried latex like opium are best extracted into:

• Dilute aqueous acid to form water-soluble salts
• Pure hexane for direct crystallization
• Cold ethanol without acidification
• Distilled water with no pH adjustment

Correct Answer: Dilute aqueous acid to form water-soluble salts

Q14. Which compound in opium is primarily responsible for its antitussive (cough suppressant) action?

• Noscapine
• Codeine
• Quinine
• Caffeine

Correct Answer: Codeine

Q15. Which physical test would indicate the presence of rubber-like polyisoprene in a dried latex sample?

• Good solubility in water
• Solubility in organic solvents such as chloroform or benzene
• Complete dissolution in dilute acid
• Immediate combustion without residue

Correct Answer: Solubility in organic solvents such as chloroform or benzene

Q16. A common adulterant added to increase bulk in dried latex products is:

• Starch
• Pure morphine
• Guttapercha
• Citric acid

Correct Answer: Starch

Q17. Which storage condition is most suitable for preserving the quality of dried latex samples?

• Open shelf at room humidity
• Airtight, cool, dry container protected from light
• Exposure to direct sunlight to keep it dry
• High humidity cold room with no ventilation

Correct Answer: Airtight, cool, dry container protected from light

Q18. Which statement describes the pharmacognostical classification of dried latex?

• It is classified under organized drugs derived from plant organs with defined tissues
• It is classified as an unorganized drug because it lacks definite cellular structure
• It is classified as an inorganic salt
• It belongs to the class of essential oils only

Correct Answer: It is classified as an unorganized drug because it lacks definite cellular structure

Q19. Which molecule is commonly used as an index alkaloid for standardization of opium preparations?

• Papaverine
• Morphine
• Nitric acid
• Citric acid

Correct Answer: Morphine

Q20. Which drying/coagulating agent is frequently used in latex processing to promote coagulation?

• Acetic acid or formic acid
• Sodium hydroxide solution
• Strong oxidizing bleach
• Pure ethanol without acid

Correct Answer: Acetic acid or formic acid

Q21. Which of the following is a major quality concern specific to dried latex materials?

• Low melting point below 0°C
• Susceptibility to oxidative rancidity and microbial spoilage
• Excessive solubility in water
• Spontaneous polymerization to cellulose

Correct Answer: Susceptibility to oxidative rancidity and microbial spoilage

Q22. Which dried latex is notable for containing the alkaloid papaverine?

• Gutta-percha
• Opium
• Natural rubber
• Chicle

Correct Answer: Opium

Q23. For pharmacological extraction of alkaloids from opium, which solvent system is commonly used after acid extraction?

• Basification followed by extraction into chloroform or ether
• Direct hot water extraction only
• Extraction into hexane without pH change
• Precipitation with ethanol immediately

Correct Answer: Basification followed by extraction into chloroform or ether

Q24. Which botanical source yields gutta-percha used in pharmacy and dentistry?

• Palaquium gutta
• Hevea brasiliensis
• Ficus elastica
• Manilkara zapota

Correct Answer: Palaquium gutta

Q25. Which of these correctly pairs a dried latex with its primary industrial or medicinal use?

• Natural rubber — dental root filling
• Gutta-percha — elastic tire manufacture
• Opium — source of narcotic analgesics
• Chicle — source of papaverine

Correct Answer: Opium — source of narcotic analgesics

Q26. Which factor most affects the polymer configuration (cis or trans) in plant-derived polyisoprenes?

• Genetic and enzymatic biosynthetic pathways in the plant species
• Storage temperature after coagulation only
• The type of container used for collection
• Exposure to sunlight for one hour

Correct Answer: Genetic and enzymatic biosynthetic pathways in the plant species

Q27. A pharmacognosy practical distinguishing natural rubber from gutta-percha is based on:

• Both dissolve equally in cold water
• Thermoplastic behaviour: gutta-percha becomes plastic on heating whereas natural rubber is elastic and more resilient
• Both are brittle and non-thermoplastic
• Only rubber contains alkaloids detectable by Dragendorff’s reagent

Correct Answer: Thermoplastic behaviour: gutta-percha becomes plastic on heating whereas natural rubber is elastic and more resilient

Q28. Which statement is true about meconic acid in opium?

• Meconic acid is an inorganic salt present in rubber
• Meconic acid is a characteristic organic acid present in opium and used in identification
• Meconic acid is the primary analgesic alkaloid
• Meconic acid is exclusive to gutta-percha

Correct Answer: Meconic acid is a characteristic organic acid present in opium and used in identification

Q29. Which documentation is essential for quality control of dried latex in a pharmaceutical laboratory?

• Pharmacopoeial monograph including identification, assay, moisture and impurity limits
• Only a verbal description from the supplier
• No documentation is required for natural products
• Only an expiry date without tests

Correct Answer: Pharmacopoeial monograph including identification, assay, moisture and impurity limits

Q30. An appropriate primary packaging material for long-term storage of dried latex samples is:

• Perforated paper bags left open
• Airtight, opaque container with a desiccant
• Thin transparent plastic film exposed to sunlight
• Wet cloth wrapping to maintain humidity

Correct Answer: Airtight, opaque container with a desiccant

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com