This document discusses approaches to controlled release oral drug delivery systems using hydrodynamically balanced systems. It describes various gastrointestinal anatomy and physiology factors that influence gastric retention time such as size, density, and food intake. Several mechanistic approaches to achieve prolonged gastric retention are outlined, including high-density systems, bioadhesive systems, swelling and expanding systems, magnetic systems, superporous hydrogels, and floating systems. Floating drug delivery systems that form rafts or generate gas are described as important approaches to obtain sufficient drug bioavailability through gastric retention.
Evaluation methods for drug excipients and container interactionSagar Savale
Excipients are one of the three components that in combination produce the medicine that the patient will take.
In therapeutic terms, the API is of primary importance because without it there is no treatment and no product.
In term of drug manufacturing all three of them are equally important so we cannot neglect anyone of them.
The interactions between excipients and the other two components (the API and the manufacturing process), and/or between two or more excipients, are fundamental to the transformation of an API into a medicinal product.
POLYMERS IN SOLID STATE, PHARMACEUTICAL APPLICATIONS OF POLYMERS AND RECENT A...Priyanka Modugu
A description on polymers in solid state, solid state properties of polymers, mechanical properties of polymers, heat of crystallization & fusion, thermodynamics of fusion & crystallization, pharmaceutical applications of polymers and recent advances in the use of polymers for drug delivery system
it provide a brief note on the drug excipient interaction and various technique to find it which is a part of preformulation studies. it gives help to mpharm(pharmaceutics) students. i.
Controlled Release Oral Drug Delivery System
Controlled drug delivery is one which delivers the drug at a predetermined rate, for locally or systemically, for a specified period of time.
Evaluation methods for drug excipients and container interactionSagar Savale
Excipients are one of the three components that in combination produce the medicine that the patient will take.
In therapeutic terms, the API is of primary importance because without it there is no treatment and no product.
In term of drug manufacturing all three of them are equally important so we cannot neglect anyone of them.
The interactions between excipients and the other two components (the API and the manufacturing process), and/or between two or more excipients, are fundamental to the transformation of an API into a medicinal product.
POLYMERS IN SOLID STATE, PHARMACEUTICAL APPLICATIONS OF POLYMERS AND RECENT A...Priyanka Modugu
A description on polymers in solid state, solid state properties of polymers, mechanical properties of polymers, heat of crystallization & fusion, thermodynamics of fusion & crystallization, pharmaceutical applications of polymers and recent advances in the use of polymers for drug delivery system
it provide a brief note on the drug excipient interaction and various technique to find it which is a part of preformulation studies. it gives help to mpharm(pharmaceutics) students. i.
Controlled Release Oral Drug Delivery System
Controlled drug delivery is one which delivers the drug at a predetermined rate, for locally or systemically, for a specified period of time.
Polymers Used in Pharmaceutical SciencesOyshe Ahmed
INTRODUCTION
CLASSIFICATION AND CHARACTERISTICS OF POLYMERS
MECHANISM OF DRUG RELEASE FROM POLYMER
BIO DEGRADATION OF POLYMERS
SYNTHESIS OF POLYMERS
POLYMERS USED IN FORMULATION OF DIFFERENT DRUG DELIVERY SYSTEM.
APPLICATION OF POLYMERS
Polymers Used in Pharmaceutical SciencesOyshe Ahmed
INTRODUCTION
CLASSIFICATION AND CHARACTERISTICS OF POLYMERS
MECHANISM OF DRUG RELEASE FROM POLYMER
BIO DEGRADATION OF POLYMERS
SYNTHESIS OF POLYMERS
POLYMERS USED IN FORMULATION OF DIFFERENT DRUG DELIVERY SYSTEM.
APPLICATION OF POLYMERS
it describes the controlled drug release by diffusion or dissolution or both or swelling or erosion and which kinetics it follows either zero,first , higuchi or peppas
Single liposomes and vesicles are successfully utilized as delivery vehicles of pharmaceuticals. However limitations of these unilamellar, single compartments led to the development of encapsulated multicompartment systems that establishes the prospect of multicomponent or multifunctional drug delivery systems. So far compartmentalization is restricted to binary systems. To realize a personalized drug delivery, a programmable linkage of n-entities of different content will be needed. Here we present both a programmable DNA-mediated linkage of three distinct vesicle populations and a novel encapsulation protocol. We discuss how the techniques established in this study might be used in personalized healthcare based on custom tailored encapsulated multicompartment vesicular drug delivery systems.
TOWARDS PERSONALIZED DRUG DELIVERY – Preparation of an Encapsulated Multicompartment System. Third International Conference on Biomedical Electronics and Devices (BIODEVICES 2010), Valencia, Spain (20-23 January, 2010), 30 minutes oral presentation.
This presentation includes introduction, physiology of GIT, factors affecting GRDDS, Advantages and disadvantages, approaches to GRDDS and their mechanism, some of the marketed products using GRDDS mechanism.
GASTRO RETENTIVE DRUG DELIVERY SYSTEM (GRDDS)JayeshRajput7
Gastro retentive drug delivery system which includes, principles concepts, advantages and disadvantages of GRDDS, Modulation of GI transit time, Approaches to extend GI transit, Buccal drug delivery systems, Principle of muco adhesion, advantages and disadvantages of GRDDS, Mechanism of drug permeation, Methods of formulation and its evaluations.
This slides deeply explains about the physiology of stomach and the suitable and non suitable drugs absorbed in stomach and the approaches in the gastrointestinal drug delivery system
Gastro retentive drug delivery system (GRDDS)Ravish Yadav
gastro retentive drug delivery system topic include
1. introduction
2.advantages
3.technology
4.evaluation
5.disadvantages
6. matrix tablet
and other relative information regarding the topic
Contents:- Introduction, Need for GRDDS, Criteria for selection of drug for GRDDS, Advantages and Disadvantages, Factor affecting gastric retention time of a drug.
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
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Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
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1. APPROACHES TO
CONTROLLED RELEASE ORAL
DRUG DELIVERY SYSTEMS
HYDRODYNAMICALLY
BALANCED SYSTEMS
BY-NIKHIL A. BHANDIWAD
M.PHARM 1ST YEAR
DEPARTMENT OF
PHARMACEUTICS
2. Introduction
• The design of hydrodynamically balanced drug
delivery system is based on prolong GI residence time
of drug in an area of the GI tract to maximize drug
reaching its absorption.
• Gastrointestinal transit time of orally administered
dosage forms are controlled by using gastro retentive
drug delivery systems (GRDDS). Need for GRDDS a
controlled drug delivery system with prolonged
residence time in the stomach.
• Floating drug delivery systems is one of the important
approaches to achieve gastric retention to obtain
sufficient drug bioavailability.
3. Which type of drugs we can formulate
GRDDS?
• We formulate the following class of drugs-
Are locally active in the stomach
(misoprostol,antacids,antibiotics against H. pylori).
Have an absorption window in stomach or in the upper small
intestine (L-dopa, P-amino benzoic acid, furosemide).
Are unstable in the intestine or colonic environment
(captopril).
Exhibit low solubility at high pH values (diazepam,verapamil).
Alter normal flora of the colon (antibiotics).
Absorbed by transporter mechanism (paclitaxel).
4. Which type of drugs we cannot
formulate as GRDDS?
• Drugs which have very limited acid solubility.
Eg: Phenytoin
• Drugs which suffer instability in gastric
environment. Eg: Erythromycin HCL
• Drugs intended for release in colon.
Eg: 5- amino salicylic acid and corticosteroids.
5. Stomach: Basic Anatomy, Physiology and
Problems
• Anatomy-
Anatomically, the stomach is
divided into 3 parts -
Fundus: the superior part
of the stomach, this lies
above the imaginary
horizontal plane passing
through the cardiac orifice.
Body: this lies between the
fundus and the antrum, and it
is the largest part of the
stomach.
Antrum: this lies in the
imaginary transpyloric plane
and to the right of the
angular notch (incisura
angularis). It joins the pyloric
canal on its right.
6. Stomach: Basic Anatomy, Physiology
and Problems
• The main function of fundus and body is storage
whereas that of antrum is mixing or grinding.
• The fundus adjusts to the increased volume during
eating by relaxation of the fundal muscle fibres.
• The fundus also exerts a steady pressure on the gastric
contents, pressing them towards the distal stomach.
• To pass through the pyloric valve into the small
intestine, particles should be of the order of 1-2 mm.
• The antrum does this grinding.
• The stomach has limitation of short residence time.
7. Stomach: Basic Anatomy, Physiology
and Problems
• Physiology-
• The Gastrointestinal tract is essentially a tube about nine
metres long that runs through the middle of the body from
the mouth to the anus and includes the throat (pharynx),
oesophagus, stomach, small intestine (consisting of the
duodenum, jejunum and ileum) and large intestine (consisting
of the cecum, appendix, colon and rectum).
• The wall of the Gatrointestinal tract has the same general
structure throughout most of its length from the oesophagus
to the anus, with some local variations for each region.
9. Stomach: Basic Anatomy, Physiology and Problems
• The stomach is an organ with a capacity for storage and mixing. The antrum region is
responsible for the mixing and grinding of gastric contents.
• The interdigestive motility pattern is commonly called the ‘migrating motor complex’
(‘MMC’) and is organised in cycles of activity and quiescence.
• Each cycle lasts 90–120 minutes and consists of four phases. The concentration of the
hormone motilin in the blood controls the duration of the phases. In the interdigestive or
fasted state, an MMC wave migrates from the stomach down the GI tract every 90–120
minutes.
• A full cycle consists of four phases, beginning in the lower oesophageal sphincter/gastric
pacemaker, propagating over the whole stomach, the duodenum and jejunum, and
finishing at the ileum. Phase III is termed the ‘housekeeper wave’ as the powerful
contractions in this phase tend to empty the Stomach of its fasting contents and
indigestible debris.
• The administration and subsequent ingestion of food rapidly interrupts the MMC cycle, and
the digestive phase is allowed to take place. The upper part of the stomach stores the
ingested food initially, where it is compressed gradually by the phasic contractions.
• The digestive or fed state is observed in response to meal ingestion. It resembles the fasting
Phase II and is not cyclical, but continuous, provided that the food remains in the stomach.
Large objects are retained by the stomach during the fed pattern but are allowed to pass
during Phase III of the interdigestive MMC.
• It is thought that the sieving efficiency (i.e. the ability of the stomach to grind the food into
smaller size) of the stomach is enhanced by the fed pattern or by the presence of food.
10. Stomach: Basic Anatomy, Physiology
and Problems
• Different features of stomach-
• Gastric pH: Fasted healthy subject 1.1 ± 0.15
• Fed healthy subject 3.6 ± 0.4
• Volume : Resting volume is about 25-50 mL
• Gastric secretion: Acid, pepsin, gastrin, mucus and some enzymes
about 60 ml with approximately 4 mmol of hydrogen ions per hour.
• Effect of food on Gastric secretion: Type of meal and its caloric
content, volume, viscosity and co-administered drugs affect gastric
secretions and gastric emptying time. The rate of emptying
primarily depends on caloric contents of the ingested meal. It does
not differ for proteins, fats and carbohydrates as long as their
caloric contents are the same. Generally gastric emptying is slowed
down because of increased acidity, osmolarity and calorific values.
11.
12. Factors influencing gastric residence time
• Density of dosage form: Dosage forms having density lower than
that of gastric fluids experience floating behaviour and greater
gastric residence time.
• Size of dosage form: In most cases larger the size greater the
gastric residence time because larger size will not allow dosage
form to quickly pass through pyloric sphincter to intestine.
• Food intake and nature of food: Usually presence of food in
stomach increases the GRT of the dosage form and increases drug
absorption by allowing it to stay at absorption site for longer time.
• Affect of age, gender, posture and disease state: Elderly persons
and females has slow gastric emptying rate. It was found that
gastric emptying in women is slower than in men regardless of
height, weight, body surface area.
• When individual rests on left side floating of dosage form will be
towards pyloric antrum.
• If rests on right side it will be in opposite direction.
14. APPROACHES TO ACHIEVE PROLONGED GASTRIC
RETENTION
1. High-density systems
2. Bioadhesive or Mucoadhesive systems
3. Swelling and Expanding Systems
4. Magnetic Systems
5. Superporous Hydrogels
6. Incorporation of Passage Delaying Food Agents
7. Ion Exchange Resins
8. Bioadhesive liposomal Systems
9. Floating systems
Raft-forming systems
Gas-generating systems
Low-density systems
Hydrodynamically Balanced Systems
15. High-Density Systems
• High density formulations include coated pellets that have
density greater than that of stomach contents (1.004 g/cm3).
• This is accomplished by coating the drug with heavy inert
materials such as barium sulphate, zinc oxide, titanium
dioxide, iron powder etc.
• The weighted pellet can then be covered with a diffusion
controlling polymer membrane.
16. Bio/Muco-Adhesive Systems
• The term 'Mucoadhesion' is commonly used to describe an
interaction between the mucin layer that lines the entire GIT and a
bioadhesive polymer.
• Bioadhesive drug delivery systems are used as a delivery device
within the lumen and cavity of the body to enhance drug
absorption in a site-specific manner.
• In this approach, bio adhesive polymers are used and they can
adhere to the epithelial surface in the stomach.
• Thus, they improve the prolongation of gastric retention. The basis
of adhesion in that a dosage form can stick to the mucosal surface
by different mechanism.
• Materials commonly used for bioadhesion are poly acrylic acid,
Chitosan, cholestyramine, sodium alginate, hydroxypropyl
methylcellulose (HPMC), sucralfate, tragacanth, dextrin,
polyethylene glycol (PEG) and polylactic acids etc.
18. Swelling and Expanding Systems
• These are the dosage forms, which after
swallowing, swell to an extent that prevent
their exit from the pylorus.
• As a result, the dosage form is retained for a
longer period of time. These systems may be
named as “plug type systems”, since they
exhibit the tendency to remain lodged at the
pyloric sphincter.
20. Magnetic Systems
• This approach to enhance the gastric retention time (GRT) is based on
the simple principle that the dosage form contains a small internal
magnet, and a magnet placed on the abdomen over the position of the
stomach.
• Groning et al. developed a method for determining gastrointestinal
transit of magnetic dosage forms under the influence of an
extracorporeal magnet, using a pH telemetering capsule (Heidelberg
capsule).
• Small magnets were attached to the capsule and administered to
humans.
• Using an extracorporeal magnet, gastric residence time of the dosage
form was found to be >6 hours compared with 2.5 hours for the
control.
• Although magnetic systems seem to work, the external magnet must
be positioned with a degree of precision that might compromise
patient compliance.
21. Superporous Hydrogels
• In this approach to improve gastric retention time (GRT) super porous
hydrogels of average pore size >100μ, swell to equilibrium size within a
minute due to rapid water uptake by capillary wetting through numerous
interconnected open pores.
• They swell to a large size (swelling ratio: 100 or more) and are intended to
have sufficient mechanical strength to withstand pressure by gastric
contraction.
• This is achieved by co-formulation with a hydrophilic particulate material,
croscarmellose sodium.
• This forms a dispersed phase within the continuous polymer matrix
duringthe synthesis (‘superporous hydrogel composites’).
• The super porous hydrogel composites stay in the human stomach for >24
hours.
• Recent advances in the field have led to 'superporous hydrogel hybrids",
which are prepared by adding a water-soluble or water dispersible polymer
that can be cross-linked after the superporous hydrogel is formed.
• Examples of hybrid agents include polysaccharides such as Sodium alginate.
Pectin and Chitosan.
23. Incorporation of Passage delaying
Food Agents
• The food excipients like fatty acids, e.g. salts of
myrestic acid change and modify the pattern
of the stomach to a fed state, thereby
decreasing gastric emptying rate and
permitting considerable prolongation of
release.
• The delay in the gastric emptying after meals
rich in fats is largely caused by saturated fatty
acids with chain length of C10-C14.
24. Ion Exchange Resin
• A coated ion exchange resin bead formulation has been
shown to have gastric retentive properties, which was loaded
with bicarbonates.
• Ion exchange resins are loaded with bicarbonate and a
negatively charged drug is bound to the resin, resultant beads
were then encapsulated in a semi permeable membrane to
overcome the rapid loss of carbon dioxide.
• Upon arrival in the acidic environment of the stomach and
exchange of chloride and bicarbonate ions take place.
• As a result of this reaction carbon dioxide was released and
trapped in a membrane thereby carrying beads towards the
top of gastric content and producing a floating layer of resin
beads in contrast the uncoated beads, which will sink quickly.
25. Bioadhesive liposomal Systems
• Mucoadhesive liposomal systems are developed
by using a polymer coating technique to facilitate
enteral absorption of poorly absorbed drugs.
• Liposomes are generally coated with
Mucoadhesive polymers such as chitosan,
carbopol, Carboxymethyl chitin and
Carboxymethyl Chitosan.
• The Mucoadhesion of the resultant Liposome
leads to an enhanced gastro retentive time of the
dosage form.
26. Floating Drug Delivery Systems
• Floating drug delivery systems is one of the important
approaches to achieve gastric retention to obtain sufficient
drug bioavailability.
• This delivery system is desirable for drugs with an absorption
window in the stomach or in the upper small intestine.
• These systems have a bulk density lower than gastric fluids and
thus remain buoyant in the stomach without affecting the
gastric emptying rate for a prolonged period of time.
• While the system is floating in the gastric contents, the drug is
released slowly at a desired rate from the system.
• After the release of the drug, the residual system is emptied
from the stomach.
• This results in an increase in the gastric retention time and a
better control of fluctuations in plasma drug concentration.
27. Requirements for Floating Drug
Delivery System
• It must maintain specific gravity lower than gastric contents
(1.004 gm/cm3).
• It must form a cohesive gel barrier.
• It should release contents slowly to serve as a reservoir.
• Depending upon the mechanism of buoyancy, two different
types of systems have been used, i.e. effervescent and non-effervescent.
29. Raft-Forming Systems
• The mechanism involved in the raft formation includes
the formation of viscous cohesive gel in contact with
gastric fluids, where in each portion of the liquid swells
forming a continuous layer called a raft.
• This raft floats on gastric fluids because of low bulk
density created by the formation of CO2.
• Usually, the system ingredients includes a gel forming
agent and alkaline bicarbonates or carbonates
responsible for the formation of CO2 to make the
system less dense and float on the gastric fluids .
30. Raft-Forming Systems
• Jorgen et al described an antacid raft forming
floating system.
• The system contains a gel forming agent (e.g.
sodium alginate), sodium bicarbonate and acid
neutralizer, which forms a foaming sodium
alginate gel (raft), which when comes in contact
with gastric fluids, the raft floats on the gastric
fluids and prevents the reflux of the gastric
contents (i.e. gastric acid) into the esophagus by
acting as a barrier between the stomach and
esophagus.
31. Gas-Generating Systems
• In this system floatability can be achieved by the generation of gas
bubbles.
• Carbon dioxide can be generated in situ by incorporation of
carbonates or bicarbonates, which react with acid either natural
gastric acid or co-formulated citric or tartaric acid in single unit
systems, such as capsules or tablets.
• Effervescent substances are incorporated in a hydrophilic polymer
and carbon dioxide bubbles are trapped in the swollen matrix.
• In vitro, the lag time before the unit floats is <l minute and buoyancy
is prolonged for 8-10 hours.
• Bilayer or multilayer systems have also been designed in which drug
and excipients can be formulated independently, and the gas
generating unit can be incorporated into any of the layers of multiple
unit systems, which avoids the 'all-or nothing' emptying process
encountered in single unit systems.
32. Low-density systems
• Gas-generating systems inevitably have a lag time
before floating on the stomach contents, during
which the dosage form may undergo premature
evacuation through the pyloric sphincter.
• Low density systems (<1 g/cm3) with immediate
buoyancy have therefore been developed.
• They are made of low-density materials
entrapping oil or air.
33. Low-density systems
• Most examples are multiple unit systems such as hollow microspheres
(microballoons), hollow beads, micro particles, emulgel beads or floating
pellets.
• At present, hollow microspheres are considered to be one of the most
promising buoyancy systems because they combine the advantages of
multiple unit systems and good floating properties.
• However like all floating systems, their efficacy is dependent on the
presence of enough liquid in the stomach, requiring frequent water.
•
34. Hydro-Dynamically Balanced Systems
• These are single-unit dosage forms, containing one or more gel-forming
hydrophilic polymers.
• The polymer is mixed with drug and usually administered in a
gelatin capsule.
• The capsule rapidly dissolves in the gastric fluid at body
temperature, and hydration and swelling of the surface polymers
produces a floating mass.
• Drug release is controlled by the formation of a hydrated boundary
at the surface.
• Continuous erosion of the surface allows water penetration to the
inner layers maintaining surface hydration and buoyancy
• Incorporation of fatty excipients gives low density formulations and
reduced penetration of water, reducing the erosion.
35. Hydro-Dynamically Balanced Systems
• To remain in the stomach for a prolonged period
of time the dosage form must have a bulk density
of less than 1.
• It should stay in the stomach, maintain its
structural integrity, and release drug constantly
from the dosage form.
• Hydrodynamically balance systems are best
suited for drugs having a better solubility in acidic
environment and also for the drugs having
specific site of absorption in the upper part of the
small intestine.
38. Evaluation
1. In vitro
Floating systems
a) Buoyancy lag time
b) Floating time
c) Specific gravity/density
Swelling systems
A. Swelling Index
• Water Uptake-It is an indirect measurement of swelling property of
swellable matrix. Here dosage form is removed out at regular interval and
weight changes are determined with respect to time. So it is also termed as
Weight Gain.
• Water uptake = WU = (Wt – Wo) * 100 / Wo
• Where, Wt = Weight of dosage form at time t
• Wo = Initial weight of dosage form
39. Evaluation
• Rate of water penetration is also important
parameter for swelling matrix, that how fast
swelling occurs is determined by equation.
40. Evaluation
• in vitro dissolution tests-In vitro dissolution
test is generally done by using USP apparatus
with paddle and GRDDS is placed normally as
for other conventional tablets. But sometimes
as the vessel is large and paddles are at
bottom, there is much lesser paddle force acts
on floating dosage form which generally floats
on surface.
41. Evaluation
• Inspite of the various modifications done to get the reproducible results,
none of them showed correlation with the in vivo conditions. So a novel
dissolution test apparatus with modification of
• Rossett-Rice test Apparatus was proposed
• Rossett-Rice test is used for predicting in-vitro evaluation of directly acting
antacid (action by chemical neutralization of acid), where HCl is added
gradually to mimic the secretion rate of acid from the stomach.
• In this modified apparatus as shown in figure, it has side arm from bottom of
beaker such that it maintains volume of 70 mL in beaker and fresh SGF is
added from burette at 2 mL/min rate. Thus sink condition is maintained.
Stirring is done by magnetic stirrer at 70-75 RPM.
42. Evaluation
• In vivo evaluation-a)
Radiology
b) Scintigraphy
c) Gastroscopy
d) Magnetic marker monitoring
43. Merits
• Delivery of drugs with narrow absorption window in the
small intestine region.
• Longer residence time in the stomach could be
advantageous for local action in the upper part of the
small intestine, for example treatment of peptic ulcer
disease.
• Improved bio-availability is expected for drugs that are
absorbed readily upon release in the GI tract such as
cyclosporine, ciprofloxacin, ranitidine, amoxycillin,
captopril, etc.
• Patient compliance by making a once a day therapy.
• Improved therapeutic efficacy.
• Improved bioavailability due to reduced P-glycoprotein
activity in the duodenum.
• Reduces frequency of dosing.
• Targeted therapy for local ailments in the upper GI tract
44. Demerits
• Floating systems has limitation, that they require high level of
fluids in stomach for floating and working efficiently. So more water
intake is prescribed with such dosage form.
• In supine posture (like sleeping), floating dosage form may swept
away (if not of larger size) by contractile waves. So patient should
not take floating dosage form just before going to bed.
• Drugs having stability problem in high acidic environment, having
very low solubility in acidic environment and drugs causing
irritation to gastric mucosa cannot be incorporated into GRDDS.
• Bio/mucoadhesives systems have problem of high turnover rate
of mucus layer, thick mucus layer & soluble mucus related
limitations.
• Swellable dosage form must be capable to swell fast before its
exit from stomach and achieve size larger than pylorus aperture. It
must be capable to resist the housekeeper waves of Phase III of
MMC.
45. CONCLUSION
• The Hydrodynamically balanced systems (HBS) are very
effective system because it is designed to prolong GI
residence time of drug in an area of the GI tract and it
maximizes drug absorption. There are many factors
which effect the gastric retention time. There are so
many problems occur to found prolong gastric
retention so use many approaches to achieved it.
• Floating Drug Delivery Systems (FDDS) or Hydro
dynamically Balanced Systems (HBS) have been
developed in order to increase the gastric residence
time (GRT).
46. References
• Journal of Pharmaceutical and Scientific Innovation ‘HYDRODYNAMICALLY
BALANCED SYSTEMS: INNOVATIVE APPROACH OF GASTRO RETENTION: A
REVIEW’ by Dubey Vivek, Arora Vandana and Singh Amit Kumar ; Volume
1(3)-May- June 2012, Pg No 16-22.
• Acta Chimica and Pharmaceutica Indica ‘A COMPREHENSIVE REVIEW ON
GASTRO RETENTIVE DRUG DELIVERY SYSTEM’ by MARINAGANTI RAJEEV
KUMAR, BONTHU SATYANARAYANA, NAGAKANYAKA DEVI PALADUGU,
NEERUKONDAVAMSI, SHEIK MUDDASAR, SHAIK IRFAN PASHA, SPANDANA
VEMIREDDY and DEEPTHI POLOJU; Vol 3(2), 2013 Pg No 149-164.
• Journal of Drug Delivery & Therapeutics , ‘ADVANCEMENTS IN
CONTROLLED RELEASE GASTRORETENTIVE DRUG DELIVERY SYSTEM: A
REVIEW’ by Makwana Ami; Sameja Krunal; Parekh Hejal; Pandya Yogi;
Volume 2(3) 2012 Pg No 12-21.