Mechanism of drug absorption Git | factor influencing absorption | non per oral extra vascular route
DEPTH OF BIOLOGY・35 minutes read
Studying Biopharmaceutics and Pharmacokinetics involves absorption, distribution, metabolism, excretion, and bio-availability of drugs, focusing on factors like formulation, pH, and biological influences. Various administration routes impact drug bioavailability and metabolism, with differences in effectiveness, speed, and potential side effects.
Insights
- The study of Biopharmaceutics and Pharmacokinetics in B. Pharmacy delves into drug absorption, distribution, metabolism, excretion, and elimination, emphasizing crucial concepts like half-life and bio-availability, with a detailed breakdown of transport mechanisms like passive diffusion, filtration, and active transport.
- Formulation of tablets involves critical steps like dry and wet granules, with excipients playing a pivotal role in ensuring proper disintegration and absorption, highlighting the significance of maintaining a balance in excipient amounts for optimal drug effectiveness and quality.
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Recent questions
What is the importance of maintaining excipient balance in tablet formulations?
Maintaining a balance in excipient amounts in tablet formulations is crucial to ensure good quality and suitable formulation methods. Excessive binding agents in tablets can prevent proper disintegration, leading to absorption issues. By carefully controlling the excipient quantities, pharmaceutical companies can optimize the tablet's properties, such as disintegration time, dissolution rate, and overall effectiveness of the drug. This balance also impacts the bioavailability of the drug, as the excipients play a significant role in how the drug is released and absorbed in the body. Therefore, proper management of excipients is essential in producing high-quality tablets that deliver the intended therapeutic effects.
How does the pH of a drug affect its absorption in the body?
The pH of a drug can significantly impact its absorption in the body. Acidic drugs tend to dissolve in the stomach, where the acidic environment facilitates their absorption. On the other hand, basic drugs dissolve better in the intestine, which has a more basic pH. This pH-dependent absorption can influence the drug's bioavailability and effectiveness in reaching its target site for action. Understanding the pH characteristics of a drug is essential for determining the optimal route of administration and ensuring that the drug is absorbed efficiently in the body.
What are the different routes of drug administration and how do they impact bioavailability?
There are various routes of drug administration, such as enteral and parenteral, each impacting the drug's bioavailability and metabolism differently. Enteric-coated tablets, for example, are designed to bypass stomach dissolution for intestinal absorption, affecting the drug's bioavailability. Sublingual administration involves placing a tablet under the tongue, allowing for fast absorption through capillaries and bypassing the liver. Buccal administration, on the other hand, involves placing a tablet between the cheek and gum, ensuring quick action and maintaining bioavailability. Rectal administration bypasses the liver and first-pass metabolism, ensuring high bioavailability. Each route of administration offers unique advantages and considerations in terms of bioavailability, absorption rates, and effectiveness of the drug in producing the desired therapeutic effects.
How do biological factors like villi and gastric emptying rate influence drug absorption?
Biological factors such as villi in the small intestine and gastric emptying rate play a crucial role in drug absorption. Villi increase the surface area available for absorption in the small intestine, facilitating the uptake of drugs into the bloodstream. The gastric emptying rate determines how quickly the stomach empties its contents into the intestine, affecting the absorption rate of orally administered drugs. Faster gastric emptying can lead to rapid drug absorption, while slower emptying may delay the drug's onset of action. Understanding these biological factors is essential for predicting and optimizing drug absorption in the body.
Why is the timing of drug intake in relation to meals important for optimal effectiveness?
The timing of drug intake in relation to meals is crucial for ensuring optimal effectiveness and absorption of the drug. Some drugs require consumption before or after eating to enhance their bioavailability and therapeutic effects. For example, taking certain medications on an empty stomach can improve their absorption rate, while others may be more effective when taken with food to reduce stomach irritation or enhance absorption. Understanding the impact of meal timing on drug absorption is essential for maximizing the drug's efficacy and ensuring that it reaches its target site for action in the body.
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Summary
00:00
Biopharmaceutics and Pharmacokinetics: Drug Absorption and Distribution
- Starting B. Pharmacy Six Semester Biopharmaceutics and Pharmacokinetics
- Subject overview: study absorption, distribution, metabolism, excretion, elimination
- Focus on half-life of the drug and bio-availability
- Units 1-5 cover absorption, distribution, metabolism, excretion, elimination, and bio-availability
- Unit 1 begins with absorption, explaining routes of administration
- Drug enters systemic circulation, reaches target site for action
- Transport system: passive diffusion, filtration, active transport
- Passive transport: no ATP used, drug moves high to low concentration
- Filtration: small pores allow drug with molecular weight <100 to cross cell membrane
- Active transport: ATP used, drug moves low to high concentration, against gradient
14:25
Optimizing Tablet Formulation for Drug Absorption
- Formulation of tablets involves steps like dry granules and wet granules, with various excipients like coloring, flavoring, stunning, and binding agents.
- Excessive binding agent in tablets can prevent proper disintegration, leading to absorption issues.
- It is crucial to maintain a balance in excipient amounts, ensuring good quality and suitable formulation methods.
- The pH of a drug can affect its absorption, with acidic drugs dissolving in the stomach and basic drugs in the intestine.
- Ionization and lipophilic nature impact drug absorption, with lipophilic drugs easily crossing cell membranes.
- Increasing a drug's lipophilicity enhances absorption by facilitating membrane crossing.
- Biological factors like villi in the small intestine and gastric emptying rate influence absorption rates.
- Timing of drug intake in relation to meals is crucial, with some drugs requiring consumption before or after eating for optimal effectiveness.
- Diseases affecting the stomach, intestine, liver, or kidney can disrupt absorption, distribution, metabolism, and excretion processes.
- Different routes of drug administration, such as enteral and parenteral, impact drug bioavailability and metabolism, with enteric-coated tablets designed to bypass stomach dissolution for intestinal absorption.
28:44
Various Routes of Drug Administration Explained
- Sublingual administration involves placing a tablet under the tongue, allowing it to dissolve slowly, leading to absorption through capillaries and bypassing the liver for fast action and increased bioavailability.
- Buccal administration entails placing a tablet between the cheek and gum, ensuring quick action, bypassing first-pass metabolism, and maintaining bioavailability, although it may cause discomfort due to the lipid-soluble nature of the drug.
- Rectal administration involves introducing the drug through the anus, useful in conditions like piles, bypassing the liver, avoiding first-pass metabolism, and ensuring high bioavailability.
- Subcutaneous injections are administered beneath the skin, ensuring bypass metabolism, good bioavailability, potency, and efficacy, although the disadvantage includes the need for a trained person and limitations in drug quantity.
- Inhalation administration involves inhaling drugs, such as general anesthetics, into the lungs for absorption through capillaries, ensuring rapid action but requiring instruments and a trained person for proper use.
- Nasal administration involves delivering drugs through the nose, ensuring good bioavailability, bypassing first-pass metabolism, but may cause discomfort and require droplet-form drugs, like the GnRH Vaccine.
- Intramuscular administration requires lipid-soluble drugs injected into muscles, offering quick action but limited drug quantity, painful injections, and the need for a trained person.
- Intravenous administration involves directly inserting drugs into blood vessels, ensuring rapid action, 100% bioavailability, and bypassing first-pass metabolism, but requiring a skilled person, causing pain, and being unsuitable for untrained individuals.
