Formulations targeting the GIT Flashcards

Question

What is loperamide hydrochloride used for (4)

Answer 1

1. antimotility drug 2. the standard treatment when rapid control of symptoms is required. 3. It can also be used for mild-to-moderate travellers' diarrhoea (e.g. where toilet amenities are limited or unavailable) 4. but should be avoided in bloody or suspected inflammatory diarrhoea and in cases of significant abdominal pain.

Answer 2

1. Bisacodyl 5 mg gastro-resistant tablets (Dulcolax®) –methacrylic acid – methylmethacrylate copolymer enteric coat 2. Docusate sodium 100 mg liquid filled soft gelatin capsules (Dulcoease®) – Polyethylene glycol (PEG) vehicle 3. Lactulose oral solution 3.3g/5mL – An example of a product with no additional formulation excipients

Answer 3

a stimulant laxative also available as suppositories.

Answer 4

believed to act as both a stimulant laxative and as a faecal softener.

Answer 5

1. a semi-synthetic disaccharide which is not absorbed from the gastro-intestinal tract 2. an osmotic laxative, which increase the amount of water in the large bowel.

Answer 6

1. Hyoscine butylbromide – Buscopan 10 mg tablets 2. Peppermint oil – Colpermin IBS Relief Capsules 3. Arachis oil (peanut) based formulation 4. Liquid-filled enteric-coated capsules - additional band of gelatin around centre of capsule to prevent leakage 5. Alverine citrate – Spasmonal® 60mg / 120mg immediate-release capsules (P) 6. Mebeverine hydrochloride – 200mg modified-release capsules (POM) – Hard-gelatin capsules filled with ethylcellulose-coated pellets 7. The choice of drug treatment depends on the nature and severity of the symptoms. Many drug treatment options for IBS are available over-the-counter.

Answer 7

1. The mode of action is local rather than systemic. 2. The enteric coating delays opening of the capsule until it reaches the distal small bowel. 3. Peppermint oil is then slowly released as the matrix passes along the gut. 4. The oil exerts a local effect of colonic relaxation and a fall of intra-colonic pressure. 5. Pharmacological studies have demonstrated that peppermint oil exerts its inhibitory effect on gastrointestinal smooth muscle by interference with the mobilisation of calcium ions.

Answer 8

1. Loperamide HCl liquid-filled soft gelatin capsules – Propylene glycol vehicle 2. Drug in solution = more rapid absorption – Symptomatic treatment of acute diarrhoea associated with Irritable Bowel Syndrome 3. Linaclotide 290 mcg capsules (Constella®) – Symptomatic treatment of irritable bowel syndrome with constipation (IBS-C) 4. Patients with IBS should be advised how on to adjust their dose of laxative or anti-motility drug according to stool consistency, with the aim of achieving a soft, well-formed stool.

Answer 9

1. a guanylate cyclase-C receptor agonist that is licensed for the treatment of moderate to severe irritable bowel syndrome associated with constipation. 2. It increases intestinal fluid secretion and transit and decreases visceral pain.

Answer 10

1. Prodrug approach to targeting the lower GIT 2. Active component is chemically bonded to an additional “carrier” compound and only released at site of action 3. Based on knowledge of colonic microflora 4. Anaerobic bacteria which are only present in the lower GIT break the functional link in the molecule 5. Sulfazalazine was the first drug to be used in this way – Releasing the active 5-aminosalicylic acid component

Answer 11

1. newer aminosalicylates 2. Balsalazide 3. Olsalazine 4. Mesalazine

Answer 12

1. headache 2. nausea 3. fever 4. rash

Answer 13

1. Sulfasalazine is a combination of 5-aminosalicylic acid (‘5-ASA’) and sulfapyridine 2. Sulfapyridine is a carrier to the colonic site of action but still causes side-effects 3. ~ 90% of a dose reaches the colon where bacteria split the molecule

Answer 14

1. Salazopyrin Tablets 500 mg – Povidone, Starch, Magnesium stearate, Silicon dioxide 2. Salazopyrin En-Tabs 500 mg – Cellulose acetate phthalate enteric coating 3. EN-Tablets should be used where there is gastro-intestinal intolerance of plain tablets. They should not be crushed or broken.

Answer 15

1. Pentasa® sachets and tablets 2. Both comprise prolonged release ethylcellulose-coated microgranules of mesalazine 3. Small granules have a consistent gastric transit time and enter the duodenum within 1 h of administration, independent of food co-administration 4. Mesalazine is continuously released from the coated microgranules throughout the GIT irrespective of pH

Answer 16

1. Consists of mesalazine linked to a carrier molecule (4-aminobenzoyl-ß-alanine) via an azo bond (-N=N-) 2. Cleavage of the azo bond by bacteria releases mesalazine as an active metabolite in the colon 3. Balsalazide and the carrier do not contribute to the pharmacodynamic action 4. Colazide 750 mg capsules

Answer 17

1. An inert dimer of 5-aminosalicylic acid 2. Cleaved by colonic bacteria to produce two active molecules of 5-ASA 3. Olsalazine is itself a relatively inert compound. 4. Absorption in the small intestine is slight. 5. On entering the colon it is split by bacteria into two molecules of 5-amino salicylate (5-ASA, mesalazine). 6. 5-ASA is believed to be principal active fragment of sulfasalazine, which has been in use for 40 years in the treatment of ulcerative colitis. 7. 5-ASA is believed to be the active form of olsalazine sodium as olsalazine has little effect in in-vitro tests or on experimental animals. 8. The clinical benefits of sulfasalazine, 5-ASA and olsalazine are evident in ulcerative colitis, but the pharmacological mechanism is not established.

Answer 18

Dipentum 250 / 500 mg capsules