FirstHope 
Law of Flow (Newton’s Law of Viscosity) states shear stress is directly proportional to velocity gradient. Law of Flow (Newton’s Law of Viscosity) explains Newtonian fluid behavior in pharmaceutical systems. This refers to the application of Newton’s law in describing fluid behavior. Newton’s Law (Restated): $\frac{F}{A} = \eta \cdot \frac{du}{dy}$ Where: F/A = applied force … Read more
Newtonian Systems show constant viscosity, independent of applied shear rate. Newtonian Systems is a fluid whose flow behavior follows Newton’s law of viscosity, which means: The viscosity remains constant regardless of the shear rate or the force applied. The relationship between shear stress (F/A) and shear rate (du/dx) is linear. Definition: A Newtonian fluid is … Read more
Rheology is the science of flow and deformation of matter, especially liquids and semisolids. In physical pharmaceutics, understanding rheology is crucial for: Designing liquid formulations (e.g., syrups, emulsions, suspensions), Semi-solids (e.g., creams, ointments, gels), And ensuring proper processing, mixing, filling, and dispensing of products. Rheology is important for: Processing (pumping, mixing, filling bottles) Product performance … Read more
Synthesis of Isoquinoline covers Bischler–Napieralski, Pictet–Spengler, and Pomeranz–Fritsch routes with key steps for drug design. Bischler–Napieralski Synthesis Reactants: β-Phenylethylamine + acyl chloride → Cyclization Reagents: POCl₃ or P₂O₅ (dehydrating agents) Steps: Acylation of phenylethylamine Cyclization under acidic conditions Dehydrogenation → Isoquinoline Pomeranz–Fritsch Reaction Reactants: Benzaldehyde + aminoacetaldehyde diethyl acetal Conditions: Acidic cyclization Reaction: Benzaldehyde + … Read more
Synthesis of Indole covers Fischer indole, Madelung, Bartoli, and Nenitzescu methods with key steps for medicinal chemistry. Fischer (Most common method) Reactants: Phenylhydrazine + Aldehyde or Ketone Conditions: Acidic, heat Example: Phenylhydrazine + Acetone → Indole (after cyclization and rearrangement) Mechanism: Hydrazone formation [3,3]-Sigmatropic rearrangement (Fischer) Cyclization and aromatization Bischler–Möhlau Indole Synthesis Reactants: Aniline + … Read more
Indole is a bicyclic heterocyclic compound found in tryptophan, alkaloids, and widely used in pharmaceuticals and organic synthesis. Chemical Formula of Indole: C₈H₇N Physical Properties of Indole: Property Value Appearance White to pale yellow crystals Melting Point ~52 °C Boiling Point ~254 °C Solubility Soluble in ethanol, ether, slightly in water Basicity Very weak (non-basic) … Read more
Reactions of Acridine involve electrophilic substitution, oxidation, and reduction processes important in pharmaceuticals and dyes. Reactions of Acridine Electrophilic Substitution (EAS) Preferred at positions 2 and 7 (central ring). Examples: Nitration: 2-nitroacridine (HNO₃ + H₂SO₄) Halogenation: Br₂ → 2-bromoacridine Nucleophilic Substitution (NAS) C-9 and neighboring positions can undergo substitution when activated (e.g., by halogen + … Read more
Synthesis of Acridine covers Bernthsen condensation, Ullmann coupling, and intramolecular cyclization for dyes and drug discovery. Bernthsen Synthesis (Classical Method) Reactants: Diphenylamine + Carboxylic acid (or acid anhydride) Catalyst: Zinc chloride (ZnCl₂) Conditions: High temperature (~250–270 °C) Reaction: Diphenylamine + Formic acid → Acridine + Water Mechanism: Involves Friedel–Crafts acylation, cyclization, and dehydration. From Anthranilic … Read more
Acridine is a nitrogen heterocyclic compound used in dyes, antiseptics, and anticancer research in medicinal chemistry. Chemical Formula of Acridine: C₁₃H₉N Physical Properties of Acridine: Property Value Appearance Yellow crystalline solid Melting Point ~110 °C Boiling Point ~345 °C Solubility Slightly soluble in water, soluble in ethanol and ether Basicity pKa ~5.5 Medicinal Uses: Used … Read more
Reactions of Isoquinoline include electrophilic substitution, nucleophilic substitution, oxidation, and reduction important in medicinal chemistry. Reactions of Isoquinoline Electrophilic Aromatic Substitution (EAS) Preferred at benzene ring positions: Especially C-5 and C-8 (similar to quinoline). EAS is harder on the pyridine ring (C-1 to C-4). Examples: Nitration: HNO₃/H₂SO₄ → 5-nitroisoquinoline Bromination: Br₂/FeBr₃ → 5-bromoisoquinoline Sulfonation: Concentrated … Read more
