Pharmaceutical Technology I Lecture 3 - Solvent Use in Oral Solutions PDF

Pharmaceutical Technology I By 3rd Stage Dr/ Ahmed Shawky Srag El-Din Solvent used in pharmaceutical Preparation Assistant Professor of Pharmaceutics and &...

Pharmaceutical Technology I By 3rd Stage Dr/ Ahmed Shawky Srag El-Din Solvent used in pharmaceutical Preparation Assistant Professor of Pharmaceutics and & Industrial Pharmacy Oral Solutions  (A) Water Water is the most widely used solvent for use as a vehicle for pharmaceutical products due to: 1. Lack of toxicity. 2. Physiological compatibility. 3. Ability to dissolve a wide range of materials. Naturally occurring water containing varying amounts of dissolved inorganic salts, usually sodium , potassium, calcium, magnesium and iron, chlorides, sulfates and bicarbonates, along with dissolved and undissolved organic matter and microorganisms. Types of Pharmaceutical Water Tap water or Purified Sterile Water for Injection, Bacteriostatic Water for drinking Water, USP. Injection, USP. water or USP Potable Water Sterile , pyrogen free, and SWFI + antimicrobial agent packaged in single units (less For multiple dosing than 1 litre in volume).  Tap water or drinking water or Potable Water Contains less than 0.1% of total solids. Clear, colorless, odorless, and neutral or only slightly acidic or alkaline due to the nature of the dissolved solids and gases (carbon dioxide contributing to the acidity and ammonia to the alkalinity of water). Unsuitable for most pharmaceutical preparations due to potential chemical incompatibilities like precipitation, discoloration, and effervescence. Used for : 1. washing 2. Extraction of crude vegetable drugs. 3. Preparation of certain products for external use. For cleaning pharmaceutical machinery and equipment, tap water can be used economically, but purified water must be used for the final rinse to prevent residue.  Purified Water, USP Contains fewer solid impurities than tap water, with a maximum of 0.001% residue. Used for preparing aqueous dosage forms, except for parenteral administration (injections). Obtained through: 1. Distillation. 2. Ion exchange. 3. Reverse osmosis.  Distillation Method Discarding the First Portion of Distillate: The initial 10% to 20% of the distillate must be discarded because it contains volatile substances commonly found in urban drinking water, which is often the starting material. Discarding the Last Portion of Water: The final 10% of the original water as Distilling to dryness could decompose the remaining solid impurities into volatile substances, contaminating the previously collected distillate.  Ion Exchange demineralizer Advantages over Distillation: Eliminates the need for heat, reducing costs Simpler equipment and easier operation with minimal maintenance. Offers more mobile facility and convenience. Ion Exchange Equipment: Water is passed through columns containing cation and anion exchangers. These exchangers are water-insoluble synthetic polymerized phenolic, carboxylic, amino, or sulfonated resins of high molecular weight.  Ion Exchange demineralizer Types of Resins: Cation (Acid) Exchangers: Replace cations in solution (e.g., Na⁺) with hydrogen ions from the resin. Anion (Base) Exchangers: Remove anions (e.g., Cl⁻) from the solution. Water purified in this manner; referred to as demineralized or deionized water.  Reverse Osmosis A type of cross-flow (or tangential flow) membrane filtration. Operation 1- Pressurized water is passed parallel to the inner side of a filter membrane. 2- A portion of the water, called permeate or influent, passes through the membrane as filtrate. 3- The remaining water, called concentrate, sweeps tangentially along the membrane , carries away the concentrated contaminants. Cross-flow system Unlike osmosis, where water flows from a less concentrated to a more concentrated solution, in reverse osmosis, water flows from a more concentrated to a less concentrated solution. thus, the term reverse osmosis Membrane Filtration Levels: Microfiltration: 0.1 to 2 µm (e.g., bacteria) Nanofiltration: 0.001 to 0.01 µm (e.g., organic compounds in the molecular weight range of 300 to 1,000) Ultrafiltration: 0.01 to 0.1 µm (e.g., viruses) Reverse Osmosis: