BPS 2110 MIDTERM 2 EXAM QUESTIONS
AND ANSWERS GRADED A+ 2026
What is Lipinski's Rule of Five? - ANS A guideline used in drug discovery to predict the
likelihood of poor absorption or permeation based on specific molecular properties.
What are the criteria for a compound to be poorly absorbed according to Lipinski's Rule of Five?
- ANS More than 5 hydrogen bond donors, more than 10 hydrogen bond acceptors,
molecular weight greater than 500, or calculated LogP greater than 5.
What are hydrogen bond donors and acceptors in the context of Lipinski's Rule? -
ANS Donors are functional groups containing -OH or -NH, while acceptors are nitrogen and
oxygen atoms with lone pairs of electrons.
How does molecular weight affect drug absorption? - ANS Larger molecules tend to be less
soluble and cross membranes less easily due to size preventing diffusion through lipid bilayers.
What is lipophilicity and why is it important for drugs? - ANS Lipophilicity refers to a
compound's affinity for lipids; effective drugs must balance lipophilicity and hydrophilicity to
dissolve in biological fluids and cross membranes.
What is LogP? - ANS The logarithm of the partition coefficient between octanol and water for
the neutral form of a drug, indicating its lipophilicity.
@COPYRIGHT 2026/2027 ALL RIGHTS RESERVED
1
, What is LogD and how does it differ from LogP? - ANS LogD is the partition coefficient at a
specific pH, relevant for ionizable compounds, while LogP is measured under non-physiological
conditions.
What are the two common methods to measure LogP? - ANS Shake-Flask method and High-
Performance Liquid Chromatography (HPLC).
How does pKa influence drug solubility? - ANS pKa controls water solubility as solubility in
aqueous environments is pH-dependent, with ionization increasing solubility.
What happens to a drug's ionization at pH < pKa? - ANS Acids are neutral, while bases are
charged.
What happens to a drug's ionization at pH > pKa? - ANS Acids are charged, while bases are
neutral.
What is the significance of the pKa range for drug absorption? - ANS Optimal absorption
occurs when pKa is within 2-3 pH units of physiological pH (7.4).
What is the pKa of water? - ANS The pKa of water is 15.7.
What is the pKa of H3O+? - ANS The pKa of H3O+ is -1.7.
What is the relevance of knowing both pKa values for a functional group? - ANS It helps
determine whether the compound will act as an acid or a base at a specific pH.
@COPYRIGHT 2026/2027 ALL RIGHTS RESERVED
2
AND ANSWERS GRADED A+ 2026
What is Lipinski's Rule of Five? - ANS A guideline used in drug discovery to predict the
likelihood of poor absorption or permeation based on specific molecular properties.
What are the criteria for a compound to be poorly absorbed according to Lipinski's Rule of Five?
- ANS More than 5 hydrogen bond donors, more than 10 hydrogen bond acceptors,
molecular weight greater than 500, or calculated LogP greater than 5.
What are hydrogen bond donors and acceptors in the context of Lipinski's Rule? -
ANS Donors are functional groups containing -OH or -NH, while acceptors are nitrogen and
oxygen atoms with lone pairs of electrons.
How does molecular weight affect drug absorption? - ANS Larger molecules tend to be less
soluble and cross membranes less easily due to size preventing diffusion through lipid bilayers.
What is lipophilicity and why is it important for drugs? - ANS Lipophilicity refers to a
compound's affinity for lipids; effective drugs must balance lipophilicity and hydrophilicity to
dissolve in biological fluids and cross membranes.
What is LogP? - ANS The logarithm of the partition coefficient between octanol and water for
the neutral form of a drug, indicating its lipophilicity.
@COPYRIGHT 2026/2027 ALL RIGHTS RESERVED
1
, What is LogD and how does it differ from LogP? - ANS LogD is the partition coefficient at a
specific pH, relevant for ionizable compounds, while LogP is measured under non-physiological
conditions.
What are the two common methods to measure LogP? - ANS Shake-Flask method and High-
Performance Liquid Chromatography (HPLC).
How does pKa influence drug solubility? - ANS pKa controls water solubility as solubility in
aqueous environments is pH-dependent, with ionization increasing solubility.
What happens to a drug's ionization at pH < pKa? - ANS Acids are neutral, while bases are
charged.
What happens to a drug's ionization at pH > pKa? - ANS Acids are charged, while bases are
neutral.
What is the significance of the pKa range for drug absorption? - ANS Optimal absorption
occurs when pKa is within 2-3 pH units of physiological pH (7.4).
What is the pKa of water? - ANS The pKa of water is 15.7.
What is the pKa of H3O+? - ANS The pKa of H3O+ is -1.7.
What is the relevance of knowing both pKa values for a functional group? - ANS It helps
determine whether the compound will act as an acid or a base at a specific pH.
@COPYRIGHT 2026/2027 ALL RIGHTS RESERVED
2
