The document discusses modulation of gastrointestinal (GI) transit time and floating drug delivery systems (FDDS). It begins with an introduction to GI transit and factors that affect transit time. It then discusses approaches to extend GI transit time including FDDS, which have a bulk density less than gastric fluids and remain buoyant in the stomach without affecting gastric emptying rate. The document covers classifications of FDDS, formulations, evaluation methods, advantages and applications. It provides examples of marketed floating drug products.
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
GRDDS is most widely used system for controlled delivery of drugs. various approaches for GRDDS is available including
floating ,gastroadhesive,high density ,unflatable system
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
GRDDS is most widely used system for controlled delivery of drugs. various approaches for GRDDS is available including
floating ,gastroadhesive,high density ,unflatable system
Introduction to colon drug delivery,Anatomy n physiology of colon,Factors affectind colon DDS,Limitations,Advantages,Approches to colon DDS,Evaluation of CDDS
Design, optimization and in vitro evaluation of gastroretentive hollow micros...SURYAKANTVERMA2
To modify the GIT time is one of the main challenge in the development of oral controlled drug delivery system.
Gastric emptying of pharmaceutical dosage form is highly variable and dependent on the dosage form and the fed/fasted state of the stomach.
Normal gastric residence time usually ranges between 5 minutes to 2 hours.
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Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
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2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
micro teaching on communication m.sc nursing.pdfAnurag Sharma
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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
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Title: Sense of Smell
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 primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
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
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1. K.B.H SS TRUST’S INSTITUTE OF PHARMACY
MALEGAON,NASHIK
GRDDS: MODULATION OF GI TRANSIT, APPROACHES
AND FLOATING DRUG DELIVERY SYSTEM
Presented By:
Osama Tauseef
M.Pharm 1st semester
Guided By:
Dr. A. B. Gangurde
Head of Department
Department of pharmaceutics
1
2. Contents
• Introduction
• Modulation of GI transit time
• Approaches to extend GI transit
• Floating drug delivery system
• Classifications
• Formulation
• Evaluations
• Advantages and Disadvantages
• Applications
• Marketed products
• Bibliography
2
3. INTRODUCTION:
Gastrointestinal Transit:
Gastrointestinal transit: The time taken by food to leave the stomach and travel through the
intestines.
The transit time for the mouth to anus: Depend upon object ingested and physiological
condition of the tract.
Factors affect transit time:
diet
medication
gender
level of physical activity
stress level that affect GI tract.
3
4. MAODULATION OF GI TRANSIT TIME:
Successful modulation of Gi transit time of drug delivery involves study
of following GI Parts
Anatomy of GI tract
Dynamics of GI tract
GI transit
Ileocecal junction
Colon and Gut flora
GI Mucus
4
5. Anatomy of GI tract:
GI tract: A group of organs joined in a long tube divided into several sections, each have
a specific function.
The tract begins with oral cavity and follows to
o pharynx
o esophagus
o stomach
o small intestine
o large intestine
o ending with rectum to anus part.
5
7. GI layers:
• inner mucosa
• Submucosa
• muscularis externa
• serosa
Stomach serves the most primarily mixing area and a reservoir that secretes:
• pepsinogen
• gastric lipase
• hydrochloric acid
7
8. Stomach section of the GI tract is normally impermeable for absorption of most materials into
the blood except water, ions, alcohol, and certain drugs such as aspirin. The human stomach
is capable of absorbing most acidic drugs and the very weakly basic drugs. Salicylic acid,
aspirin, thiopental, secobarbital and antipyrine, which are undissociated in the acidic gastric
contents, were readily absorbed.
Small intestine, the major digestive and absorptive site of the GI tract, providing an extended
surface area.
The last part of the GI tract is the large intestine extending from the ileum to the anus with 1.5
m long and 6.35 cm in diameter that’s work for water absorptive roles.
8
9. GI tract is always in a state of continuous motility mainly there are 2 types of motility
patterns
Digestive mode
Inter digestive mode
This mode consist of four distinct phases:
I. Period of no contraction
II. Period of intermittent contractions
III. Period of regular contractions at maximal frequency
IV. Period of transition between phase 3 and phase I
Average duration of these 4 phases is 90-120 min, this can be influenced under diseases
states.
Phase 3 serves a role of clearing all indigestible materials from stomach and intestine.
Dynamics of GI tract:
9
10. GI transit:
o The transit of food through the stomach, small intestine and colon for digestion and
absorption of nutrients.
o The fasted state emptying of liquid Is independent of presence of any indigestible solid in stomach.
o The suggested DDS should be administered with small volume of liquid for prolongation
GI emptying time.
GI TRANSIT TIME 10
11. Colon and Gut flora:
The high water absorption capacity of the colon.
The availability of most drugs to the absorptive membrane is low.
The human colon has over 400 distinct species of bacteria as resident flora.
Reactions carried out by gut flora are azoreduction and enzymatic cleavage.
These metabolic processes may be responsible for the metabolism of many
drugs and may also be applied to colon-targeted drug delivery.
Ileocecal junction:
This serves mainly to ensure the unidirectional flow of luminal contents from small to large
intestine.
11
12. GI MUCUS:
Mucus is continuously secreted by goblet cells located throughout GIT.
Fresh mucous is very thick and becomes diluted and less thick near lumen, thickness
varies upon various region in GIT.
Main function is to protect surface Mucosal cell from gastric acid. Chemical
composition is glycoproteins.
Presence of mucus in GIT that is prolong transit time by application of bio (muco)
adhesive polymers.
GI MUCOSA 12
13. APPROACHES TO EXTEND GASTRICTRANSIT TIME:
Prolonged gastric retention time in the stomach could be advantageous for local action in the
upper part of the small intestine
Eg : Treatment of peptic ulcer In the few decades several stomach specific and gastro
retentive approaches being designed and developed including
13
15. Floating Drug Delivery Systems (FDDS)
Floating Oral Drug Delivery System (FDDS) are retained are useful for drugs that
are poorly soluble or unstable in intestinal fluids.
Floating drug delivery system (FDDS) have a bulk density less than gastric fluids and
so remain buoyant in the stomach.
without affecting the gastric emptying rate for a prolonged period of time.
While the system is floating on the gastric contents, the drug is released slowly at the
desired rate from the system.
release of drug, the residual system is emptied from the stomach.
This results in an increased GRT and a better control fluctuations in plasma drug
concentration.
15
17. 1) Effervescent Floating Dosage Forms:
A drug delivery system can be made to float in the stomach by incorporating a floating chamber
, which may be filled with vacuum, air or inert gas.
Volatile liquid containing system Gas generating systems
These have an inflatable chamber contains a
liquid e.g. ether, cyclopentane
These buoyant delivery systems utilizes effervescent reaction
between carbonate/bicarbonate salts and citric acid to liberate CO2
gasifies at body temperature to cause the
inflation of the chamber in the stomach
which gets entrapped in the jellified hydrocolloid layer of the system,
thus decreasing its specific gravity and making it float over chime.
For floating contain a hollow deformable
unit
The system consists of a sustained release (SR) pill as seed,
surrounded by double layers
Two chamber system: first contains the
drug and the second chamber contains the
volatile liquid.
The inner layer is an effervescent layer containing sodium
bicarbonate and tartaric acid. The outer layer is of a swell able
membrane layer containing PVA, shellac etc.
17
18. 2) Non-effervescent systems:
1) Colloidal gel barrier systems / Single Layer Floating Tablets:
Hydrodynamically balanced system (HBS), which contains drugs with gel forming hydrocolloids.
These systems incorporate one or more gel forming, highly swellable, cellulose type hydrocolloids,
polysaccharides and matrix forming polymers.
On coming in contact with gastric fluid, the hydrocolloids in the system hydrate and form a
colloidal gel barrier around its surface. This gel barrier controls the rate of fluid penetration into the
device and consequent release of the drug.
18
19. • This technology is based on the encapsulation of a drug reservoir
• Inside a micro porous compartment with apertures along its top and bottom walls.
• The peripheral walls of the drug reservoir compartment are completely sealed
• To prevent any direct contact of the gastric mucosal surface with the undissolved
drug.
2) Micro porous compartment systems
• A bi-layer tablet contain two layer one immediate release layer which
releases initial dose from system.
• the another sustained release layer absorbs gastric fluid.
• forming an impermeable colloidal gel barrier on its surface,
• And maintain a bulk density of less than unity and thereby it remains buoyant in
the stomach.
3) Bi-layer floating tablets:
19
20. • Multiple unit floating dosage forms have been developed from freeze-dried calcium alginate.
• Spherical beads of approximately 2.5 mm in diameter can be prepared by dropping a sodium
alginate solution in to aqueous solutions of calcium chloride causing precipitation of calcium
alginate.
• The beads are then separated snap and frozen in liquid nitrogen, and freeze dried at 40°C for 24
hours,
• Leading to the formation of porous system, which can maintain a floating force over 12 hours.
Alginate beads:
20
21. There are various approaches in delivering substances to the target site in a controlled release fashion.
One such approach is using polymeric micro balloons as carrier for drugs.
Hollow microspheres are known as the micro balloons.
Micro balloons were floatable invitro for 12 hrs., when immersed in aqueous media.
Radio graphical studies proved that micro balloons orally administered to human were dispersed in the upper
part of stomach and retained there for three hrs.
Against peristaltic movements.
Micro balloons / Hollow Microspheres
21
22. formulation:
Polymers and other ingredients used in preparations 0f floating drugs:
ingredients Examples
Polymers HPMC , Calcium alginate, ethyl cellulose, CMC, Polyethylene
glycol, polycarbonate, PVA, Sodium alginate, PVP and Carbopol.
Inert fatty materials Beeswax, fatty acids, long chain fatty alcohols.
Effervescent agents Sodium bicarbonate, citric acid, tartaric acid, CG (Citro glycine)
Release rate accelerants lactose, mannitol.
Release rate retardants Dicalcium phosphate, talc, magnesium stearate.
Low density material Polypropylene
Buoyancy increasing
agents
Ethyl cellulose
22
23. Preparation of floating tablets:
Floating tablets were prepared by both wet granulation and direct compression method.
In the wet granulation method:
granules were prepared using absolute ethanol as granulating agent.
Lubricants and glidants were added one after to the granules and mixed each time by tumbling
process in a dry bottle.
Accurately weighed amount of granules (containing 240 mg of drug and polymers) were
placed on the die cavity and a preparatory pressing was made.
suitable compression force such that the tablet hardness was 2, 4 and 8 kg/cm2 .
In the direct compression method:
the powders after passing through appropriate sieves were mixed and compressed directly in a
similar method mentioned above. The amount of polymers was optimized to obtain
formulations that would afford 90% release of the drug in 12 hrs.
23
24. A. In Vitro Methods
1) Floating lag time and floating time:
• The test for floating time measurement is usually performed in stimulated gastric fluid or 0.1 N HCl
maintained at 37 0C.
• It is determined by using USP dissolution apparatus. The time taken by the dosage form to float is
termed as floating lag time.
• . The system to check continuous floating behavior contains a stainless steel basket connected to a metal
string and suspended from a Sartorius electronic balance.
• spread sheet could automatically pick up the reading on the balances.
• data was collected at 30 sec interval.
• baseline was recorded and subtracted from each measurement.
Evaluations
24
25. 2) Dissolution study
A 100-ml glass beaker was modified by adding a side arm at the bottom of the beaker.
The dissolution medium and allow collection of samples.
A burette was mounted above the beaker to deliver the dissolution medium at a flow rate of 2
ml/min to mimic gastric acid secretion rate.
The drug release followed zero-order kinetics in the proposed method.
3) Swelling index:
An in vitro measuring apparatus has been conceived to determine the real floating capabilities of
buoyant dosage forms as a function of time.
It operates by measuring the force equivalent to the force in the fluid.
This force determines the resultant weight of the object.
when immersed and may be used to quantify its floating or non floating capabilities.
25
26. B. In vivo method
1) X-Ray method:
X-Ray is a very popular evaluation parameter for floating dosage form now a day.
It helps to locate dosage form in the GIT and by which one can predict and correlate the gastric
emptying time and the passage of dosage form in the GIT.
2) gamma-Scintigraphy:
Gamma -Emitting radio isotopes compounded the state-of-art for evaluation of gastro retentive formulation
in healthy volunteers.
A small amount of a stable isotope .
The main drawbacks of gamma - scintigraphy are the associated ionizing radiation for the patient.
the limited topographic information, low resolution inherent to the technique and the complicated and
expensive preparation of radiopharmaceuticals.
26
27. 3) Gastroscopy:
It comprises of peroral endoscopy, used with a fiberoptic and video systems.
It is suggested that gastroscopy may be used to inspect visually the effect of prolonged stay in
stomach on the FDDS.
Alternatively, FDDS may be drawn out of the stomach for more detailed evaluation.
4) Ultrasonography:
Ultrasonic waves reflected substantially different acoustic impedances across interface enable the
imaging of some abdominal organs. Most do not have sharp acoustic mismatches across their
interface with the physiologically. Therefore, Ultrasonography is not routinely used for the
evaluation of FDDS. The characterization included assessment of intragastric location of the
hydrogels, solvent penetration into the gel and interactions between gastric wall and FDDS
during peristalsis.
27
28. Advantages disadvantages
Drug complete absorption is achieved. The drug which is unstable in the acidic
environment
Targeted therapy for the local site in the stomach
part can be achieved.
solubility and stability problem in the stomach.
Drug concentration fluctuation problem is reduced
in case of FDDS.
Drugs which undergoes first pass metabolism – not
suitable.
Floating system shows improved selectivity in
receptor activation
Drugs which make irritation to gastric mucosa.
Reduced counter activity of the body is achieved Dosage form required minimum 200 to 250ml of
water for administration.
Extended effective concentration is showed. Floating tablet has not having significant advantage
over the conventional dosage form.
At the colon, junction minimized adverse activity is
achieved.
28
29. Application of floating drug delivery system:
Enhanced bioavailability
The bioavailability of the drug is increased significantly enhanced when comparison to the
administration of non floating type of system polymeric formulations.
Sustained Drug Delivery
Hydro Dynamically Balanced System which overcomes the gastric residence problem by retaining
in the stomach for longer period due to having bulk density <1 as a result it floats in gastric
contents.
Site-Specific Drug Delivery
These systems are more advantageous particularly for drugs that are specifically absorbed from stomach
or proximal part of the small intestine, e.g., furosemide.
Furosemide absorbed primarily from stomach then by the duodenum.
29
30. Bioavailability or Absorption Enhancement:
Drugs which are absorbed from the upper part of the gastrointestinal tract are have poor
bioavailability,
because of site specific absorption hence potential candidates are formulated as a floating drug
delivery systems and maximizing their absorption.
Marketed product
1. Madopar: levodopa and benserzide
2. Valrelase: diazepam
3. Liquid gavison: alginic acid and sodium bicarbonate
4. Topalkan: aluminum magnesium antacid
5. Almagate flatcoat: antacid
30
31. Bibliography
Hirtz J. The GIT absorption of drugs in man: a review of current concepts and methods of
investigation. Br J Clin Pharmacol. 1985;19:77SY83S.
Desai S. A Novel Floating Controlled Release Drug Delivery System Based on a Dried Gel Matrix
Network [master’s thesis]. 1984 Jamaica, NY, St John’s University.
Singh BN, Kim KH. Floating drug delivery systems: an approach to oral controlled drug delivery
via gastric retention. J Control Release. 2000;63:235Y259.
Soppimath KS, Kulkarni AR, Rudzinski WE, Aminabhavi TM. Microspheres as floating drug
delivery system to increase the gastric residence of drugs. Drug Metab Rev. 2001;33:149Y160.
Atyabi F.,Sharma H.L., Mohammad H. AH. and Fell J. T., Controlled drug release from coated
floating ion exchange resin beads. Journal of Controlled Release.1996;42: 25- 28.
31