PHR2021: Lab 5

Learning objectives

  • Prepare and dispense mixtures of insoluble therapeutic agents
  • Do so with correct methods (mortar and pestle)
  • Generate appropriate documentation and labelling
PHR2021: Lab 5

Tips

Before commencing

  • Check prescriptions for doses, legality etc.
  • Complete the batch & prescription record
  • Look up and record the solubilities of the ingredients

During preparation

  • Choose appropriate equipment and container
  • Make up to volume during measurement
  • Storage requirement - What does APF say?
PHR2021: Lab 5

Batch Record

Name: Trimethoprim Mixture (CF) 10 mg/mL APF
Batch Number: <whatever>

Batch # Exp Date Ingredient Formula QD
TRI0715 DEC 2025 Trimethoprim 600 mg 2 tablets
VOSU250321 FEB 2027 Vehicle for Oral Suspension USP NF 30 mL 30 mL
VOSO260123 FEB 2027 Vehicle for oral solution USP NF to 60 mL to 60 mL
PHR2021: Lab 5

USP32 NF: Vehicle for Oral Solution

Ingredient Quantity
Sucrose 80 g
Glycerin 5 g
Sorbitol 5 g
Sodium Phosphate, Dibasic 120 mg
Citric Acid 200 mg
Potassium Sorbate 100 mg
Methylparaben 100 mg
Purified Water to 100 mL
PHR2021: Lab 5

USP32 NF: Vehicle for Oral Suspension

Ingredient Quantity
Cellulose, Microcrystalline 800 mg
Xanthan Gum 200 mg
Carrageenan 150 mg
Carboxymethylcellulose Sodium (High Viscosity) 25 mg
Citric Acid 250 mg
Sodium Phosphate, Dibasic 120 mg
Simethicone 0.1 mL
Potassium Sorbate 100 mg
Methylparaben 100 mg
Purified water to 100 mL
PHR2021: Lab 5

Dose Required?

Jane (3 y/o) weighs 15 kg

According to APF23:

  • Treatment dose (for acute UTI): 3–4 mg/kg (max 150mg) 12-hourly

  • Prophylaxis: 2mg/kg at night

  • Why is the given dose a little low?

Could the patient have renal dysfunction?

N.B. You would, in practice, raise an alarm to the Rxcriber, but today we will proceed with the given dose.

PHR2021: Lab 5

Prescription Record

  • Date: Today's Date
  • Patient's Name: Jane Hannon
  • Patient's Address: 18 Gordon St, Footscray
  • Copy of prescription: As provided
  • Batch No: .
  • Prescriber: Leanne Tang
  • Prescription No.: KD83011
  • Dispensing Pharmacist: Your Initials
PHR2021: Lab 5

Label

KEEP OUT OF REACH OF CHILDREN

SHAKE WELL BEFORE EACH USE (J)

Trimethoprim Mixture CF 10 mg/mL APF (60 mL)
Give THREE (3) mL by measure twice daily at 12-hour intervals for 5 days

Ms Jane Hannon
Prescription No.
Date
Dr L Tang
Dispenser's Initials
Expiry Date: 60 days

Preservative: 0.1% w/v methylparabens and 0.1% w/v potassium sorbate
PROTECT FROM LIGHT (Amber) REFRIGERATE DO NOT FREEZE (6)

Name, Address & Tel. No. of Pharmacy and Proprietor's Name

PHR2021: Lab 5

Corollary

  • Suggested CALs:
CAL 7 CAL 7a CAL J
PHR2021: Lab 5

Corollary II

For labelling practice

  • Bring a fineliner

APF25 says Mixture CF, APF26 says Mixture

Calculate the quantity of each ingredient required for the total amount to be prepared. Accurately weigh/measure each ingredient. Heat about 30 mL of Purified Water to 70 to 75. Add the Glycerin and Methylparaben, and stir until the Methylparaben is dissolved. Add the Dibasic Sodium Phosphate, Citric Acid, Potassium Sorbate, and Sorbitol, and mix well. Add the Sucrose, and mix until dissolved; remove from the heat, and allow to cool. Add sufficient Purified Water to volume, and mix well. Adjust the pH if necessary. Package, and label. Packaging and storage— Package in a tight, light-resistant container, and store at controlled room temperature.

Calculate the quantity of each ingredient required for the total amount to be prepared. Accurately weigh/measure each ingredient. Heat about 90 mL of the Purified Water to 70 to 75. Dissolve the Methylparaben, followed by the Citric Acid, Dibasic Sodium Phosphate, and Potassium Sorbate in the heated water. Remove from the heat. Constantly mixing, slowly sprinkle on the Microcrystalline Cellulose, Xanthan Gum, Carrageenan, and Carboxymethylcellulose Sodium. Continue to stir until fully hydrated, add the Simethicone, and mix well. Add sufficient Purified Water to volume, and mix well. Adjust the pH if necessary. Package, and label. Packaging and storage— Package in a tight, light-resistant container, and store at controlled room temperature. Labeling— Label it to indicate that it is for use in compounding oral solutions and suspensions.

Microbiology and Immunology explanation - Trimethoprim is a bactericidal agent that inhibits bacterial dihydrofolate reductase, an enzyme involved in the synthesis of folate. Folate is essential for DNA synthesis and cell division. - Bacteria can develop resistance to trimethoprim through various mechanisms, including: - Mutations in the target enzyme (dihydrofolate reductase) that reduce the drug's binding affinity. - Increased production of the target enzyme, leading to reduced drug efficacy. - Active efflux pumps that expel the drug from bacterial cells. - Bacteria can also acquire resistance genes from other bacteria through horizontal gene transfer, which can lead to the emergence of multidrug-resistant strains. - The use of suboptimal doses can contribute to the development of resistance by allowing bacteria to survive and adapt, leading to the selection of resistant strains. This is particularly concerning in the context of multidrug-resistant bacteria, where treatment options become limited and less effective. - Therefore, it is important to use appropriate doses of antibiotics to minimise the risk of resistance development and ensure effective treatment.

Morning and night is fine Same instruction in the morning then at night/evening is also fine Refer to National Standard for Labelling of Dispensed Medicines (NSLDM) for more information on labelling practices: https://www.safetyandquality.gov.au/publications-and-resources/resource-library/national-standard-labelling-dispensed-medicines https://shorturl.at/0K1fS