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Buffers are integral to maintaining proper function and stability in both pharmaceuticals and biological systems.
Pharmaceutical Buffers
Purpose
Stability: Many drugs are pH-sensitive; buffers maintain pH to prevent degradation.
Solubility: The solubility of active ingredients can depend on pH.
Efficacy and Safety: Proper pH ensures optimal drug action and minimizes irritation.
Applications
Injectable Preparations: Must match physiological pH to avoid tissue damage.
Ophthalmic Solutions: Buffered to match the pH of tears (~7.4) for comfort.
Oral Medications: Buffers protect active ingredients from stomach acid or aid absorption.
Common Buffer Systems
Citrate Buffers: Used for a pH range of 3.0–6.2.
Phosphate Buffers: Effective between pH 5.8–8.0.
Acetate Buffers: Used in the pH range of 3.6–5.6.
Biological Buffers
Role in Physiology
Homeostasis: Buffers maintain constant pH in bodily fluids, crucial for life.
Enzyme Activity: Enzymes have optimal pH ranges; buffers ensure these conditions.
Metabolic Processes: pH affects metabolic pathways and energy production.
Major Biological Buffer Systems
Bicarbonate Buffer System
Predominant in blood plasma.
Regulates pH through respiratory (CO₂ exhalation) and renal (bicarbonate excretion) mechanisms.
Phosphate Buffer System
Active in intracellular fluids and kidneys.
Important in urine pH regulation.
Protein Buffers
Amino acids and proteins act as buffers due to their functional groups.
Hemoglobin in red blood cells buffers pH during oxygen and carbon dioxide transport.
Here's a small table summarizing body fluids, their pH values, and their buffer systems:
Body Fluid | pH Value | Body Fluid | pH Value | Buffer System |
Blood Plasma | 7.35 - 7.45 | Blood Plasma | 7.35 - 7.45 | Bicarbonate (HCO₃⁻/H₂CO₃) |
Intracellular Fluid | ~7.0 | Intracellular Fluid | ~7.0 | Phosphate (H₂PO₄⁻/HPO₄²⁻) |
Cerebrospinal Fluid | 7.4 | Cerebrospinal Fluid | 7.4 | Bicarbonate (HCO₃⁻/H₂CO₃) |
Gastric Fluid | 1.5 - 3.5 | Gastric Fluid | 1.5 - 3.5 | None (strong hydrochloric acid) |
Urine | 4.5 - 8.0 | Urine | 4.5 - 8.0 | Phosphate and ammonia systems |
This table highlights key buffer systems that help maintain pH stability in different body fluids.
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