Pharmaceutical Chemistry and Analysis Flashcards
7 cards from real KAPS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Pharmaceutical Chemistry and Analysis flashcards as text
A drug with a pKa of 4.5 is administered orally. In the stomach (pH 1.5), the drug exists predominantly as:
Answer: Ionized (acid form)
For a weak acid with pKa 4.5 at pH 1.5, the pH < pKa, so the drug is predominantly in the ionized (protonated acid) form — actually unionized for a weak acid; at pH 1.5 (below pKa 4.5), the acidic drug is predominantly unionized (HA form).
Which analytical technique provides both molecular weight and structural fragmentation information simultaneously?
Answer: Mass spectrometry
Mass spectrometry ionizes molecules and measures mass-to-charge ratios of the parent ion and fragment ions, giving MW and structural data.
The Maillard reaction in pharmaceutical formulations occurs between:
Answer: Primary amines and reducing sugars
The Maillard reaction is a non-enzymatic browning reaction between primary amines (e.g., drug amine groups) and reducing sugars used as excipients.
In titrimetry, what is the primary purpose of a primary standard?
Answer: To standardize the concentration of the titrant solution accurately
A primary standard is a highly pure, stable compound used to accurately determine (standardize) the exact concentration of a titrant.
Which phenomenon describes the ability of a drug molecule to exist in multiple crystalline forms with different physicochemical properties?
Answer: Polymorphism
Polymorphism refers to the existence of a drug in two or more distinct crystalline forms with different packing arrangements, affecting solubility and stability.
Which functional group is responsible for the characteristic absorption around 1710 cm⁻¹ in an IR spectrum?
Answer: C=O stretch of carbonyls
The carbonyl C=O stretch typically absorbs strongly near 1710 cm⁻¹ in ketones and carboxylic acids in IR spectroscopy.
Accelerated stability testing of pharmaceuticals is conducted at elevated temperatures and humidity primarily to:
Answer: Predict shelf-life using the Arrhenius equation
Accelerated stability studies use elevated conditions to accelerate degradation; the Arrhenius equation extrapolates data to predict shelf-life at storage conditions.