All lectures dbe Flashcards
What can particle size affect?
- Flowability
- Solubility
- Bioavailability
- Settling rate of suspensions
- Tolerability of some dosage forms
Give milling methods
- Cut
- Attrition
- Impact
- Compact
- Combined attrition and impact
Impact methods
Vibration mills, hammer mills
Compression methods
end runner mill, roller mill
combined impact and attrition
pin mill, ball mill
what are impact methods used for?
brittle. materials
what are attrition methods used for?
ointjments , solid in suspensions and pastes
What are cutter mills used for?
Elastic, fibrous materials like root or wood
WHat are the methids to analyse particle size?
Direct methods - seiving, micropscopy. Indirect methods - permeability, sedimentation rate
What are the different particle size distributions?
- Monosized distribution
- Positively skewed
- Bimodal
- Normal
what are the microsocpy mathods?
Light methods, Electron microco[py
Do vegeatables contain vitamin B12?
No, only if they contaminated by microorganisms
What is the cellular requirement of b12?
2 reactions in the body.
1. DNA synthesis
2. Methionine Synthesis
Where is intrinsic factor produced?
In the parietal cells
What happens if an inadequate amount of B12 is absorbed?
Megaloblastic anaemia
What is pernicious anemia?
Autoimmune atrophic gastritis. Destruction of parietal cells, leading to a lack of intrinsic factor. Can also be caused by antibodies directed against intrinsic factor
What does pernicois anaemia cause?
achlorhydria - prodution of gastric acid is low or absent
What drugs cause b12 deficiency?
Metformin, cholchicine, PPI, H2 antagonist, oral contraceptives, HRT
What are the cellular requirements of folate?
crucial for the transport on one carbon unit to amino acid, nucleotides and other biomolecules
absorption of folates
Dietary Sources: Folate is obtained from the diet through the consumption of foods rich in folate, such as leafy green vegetables, legumes, fruits, fortified cereals, and liver.
Polyglutamate to Monoglutamate Conversion: In the food sources, folates exist as polyglutamates, which are multiple glutamate molecules linked together. Before absorption, these polyglutamates need to be converted into monoglutamates (single glutamate molecule) to become bioavailable.
Folate Hydrolysis: In the duodenum, polyglutamate folates are hydrolyzed by the enzyme folate conjugase (or folate hydrolase) into monoglutamate forms. This step is essential to render folates absorbable.
Active Transport: The monoglutamate folates are then actively transported across the apical membrane (the surface facing the lumen of the intestine) of the intestinal cells. This active transport mechanism requires energy and is regulated by carrier proteins, including the reduced folate carrier (RFC) and the proton-coupled folate transporter (PCFT).
Intracellular Processing: Inside the intestinal cells, folates undergo further processing, including the conversion of folate derivatives to the biologically active form, 5-methyltetrahydrofolate (5-MTHF). 5-MTHF is the primary circulating form of folate in the blood.
Transport to the Circulatory System: Once converted to 5-MTHF, folates are transported across the basolateral membrane (the surface facing the blood) of the intestinal cells and then enter the bloodstream.
Transport in the Blood: In the blood, 5-MTHF is bound to carrier proteins, primarily albumin and other specific folate-binding proteins.
Tissue Uptake: 5-MTHF is taken up by various tissues and cells throughout the body, where it participates in essential cellular processes, as described in the previous response
Metformin mechanism of action?
Inhibition of mitochondrial respiratory chain complex 1
- Inhibits ATP synthesis
- Increases AMP
- Activates AMPK
- Phosphorylation and inhibition of CRTC2
- Inhibition of gluconeogenesic genes
What are the side effects of metformin?
GI side effects
B12 deficiency
Lactic acidosis
Does metformin cause hypoglycaemia?
No
Name sulfonylureas
Glibenclamide
Glicazide
What are the side effects of sulfonylureas
Hypoglycaemia
Weight gain
When should meglitinides be taken?
Before meals
What is the difference between meglitinides and sulfonylureas?
Meglitinides have a rapid onset and short duration of action
What are the side effects of thiazidionideiones?
Water retention and weight gain
Name GLP1 analogues
Exenatide
Liraglutide
Semaglutide
Name DPP4 inhibitors
Linagliptin. Alogliptin. sitagliptin
What can reverse the symptoms of t2d
Very low calorie diet
What are the tests for pancreatitis?
Faecal elastase
Fat soluble vitamins
What are the mechanisms that inhibit the insulin pathway?
- PTP1b
- PTEN
- PKC
- DAG
- Ceramide
which patients are thioziodinediones contraindicated in?
heart failure, fractures, haematuria
What drugs are third line for diabetes?
GLP1 analogues
