Hello there Nadesh Kwakye! I'd be happy to guide you through the process of calculating cumulative drug release percentage. It's an essential step in pharmaceutical research. Here's a step-by-step procedure:

**Materials and Equipment:**

- Loaded drug sample

- Spectrophotometer

- PBS (Phosphate Buffered Saline) solution with ethanol

- Glass vials

- Pipettes

- Stopwatch or timer

**Procedure:**

**1. Prepare Your Sample:**

- Start with your loaded drug sample. You mentioned you weighed 20mg of the loaded sample.

**2. Set Up Release Media:**

- Prepare your release media, which is PBS/ethanol solution. Ensure it's well-mixed.

- You mentioned that you're replacing 3ml of the solution, so initially, you have 10ml in total.

**3. Begin the Experiment:**

- Start your timer or stopwatch.

**4. Withdraw Sample:**

- At specific time intervals, withdraw a small volume of the release media. You mentioned 3ml. This is your "sample."

**5. Measure Absorbance:**

- Take the absorbance measurement of your sample using the spectrophotometer.

- Be sure to measure at a wavelength suitable for curcumin detection.

**6. Replace Sample:**

- After measuring, immediately replace the volume you withdrew (3ml) with fresh PBS/ethanol solution to maintain a constant volume.

**7. Record Data:**

- Record the absorbance values along with their respective time points.

**8. Calculate Drug Concentration:**

- Using your absorbance data, you can calculate the concentration of curcumin in each sample. You might need a standard curve or calibration equation for this, relating absorbance to concentration.

**9. Calculate Cumulative Drug Release Percentage:**

- To calculate the cumulative drug release percentage at each time point, use the following formula:

Cumulative Drug Release Percentage = Total Released Drug (mg) divided by Total Drug in the Sample (mg) times 100

- Total Released Drug (mg) is the sum of the drug released at each time point.

- Total Drug in the Sample (mg) is the initial amount of drug in your 20mg sample.

**10. Plot Your Data:**

- Create a graph with time on the x-axis and cumulative drug release percentage on the y-axis. This will show how drug release changes over time.

**11. Analysis:**

- Analyze your data to understand the drug release kinetics and behavior of your formulation.

Remember to perform the experiment under controlled conditions, maintain a consistent temperature, and handle samples carefully to ensure accurate results. Always refer to your specific experiment's protocol and any relevant standard operating procedures. Good luck with your drug release studies!

Dear Nadesh, the procedure for finding out cumulative release depends primarily on the encapsulation/delivery system you are working on. Whether you are using nanoparticles or emulsions or hydrogels or micelles for encapsulation, please mention. Only then, one can tell you the detailed stepwise procedure.

Thanks.

@Kaushik Shandilya thank you for your answer. This is very helpful.

Dear Pawandeep, I am using nanoparticles for my drug release studies. Thank you.