Aim:- To determine the moisture content of crude drug sample  



BACKGROUND:-

                                  Moisture content determination is important, not only to know excess water but also in conjunction with suitable temperature moisture will lead to the activation of enzymes and gives suitable conditions to the proliferation of living organisms. As most vegetable drugs contain all the essential food requirements for mold, insects, and mites, deterioration can be very rapid, once an infestation has taken place. Various methods for moisture determination are loss on drying, separation, and measurement of moisture, chemical methods, electrometric methods, and spectroscopic methods as per IP.


Theory:- 

                     In crude drug evaluation, physical methods are used to determine the solubility, boiling point swelling index, freezing point, foaming index, refractive index, melting point, water content, volatile oil content, and other physical characteristics of the herb material. 

       Physical evaluation:- It is a process of evaluation by which we can determine some of the physical properties of the crude drug and these are essential for the determination of the purity of the drug.

  The moisture content of a drug will be responsible for the decomposition of crude drugs either producing chemical change or microbial growth. So the moisture content of a drug should be determined and controlled. The moisture content is determined by heating a drug at 105°C in an oven to a constant weight. 

   Significance of Moisture content determination of crude drug:- 

1. Moisture content affects the processibility, shelf-life, usability, and quality of the Crude drug sample. Accurate moisture content determination, therefore, plays a key role in ensuring quality in Pharmaceutical practices. 

2. In conjunction with suitable temperature moisture will lead to the activation of enzymes and gives suitable conditions to the proliferation of living organisms. So the moisture content of a crude drug sample should be determined for its optimum therapeutic efficacy. 

 3. As moisture affects the stability of some drug substances it should be controlled, for that purpose determination of moisture content is very significant. 

4. The presence of excess moisture favors the growth of the microorganism and deteriorates the crude drug, so moisture content should be within a specified limit which is acceptable.

Requirements:-

 Apparatus:- Petri dish, Spatula

 Chemical requirement:- Starch [2 gm.](Crude drug sample) 

Instruments:- Weighing machine, Hot air Oven. 





Procedure:- 

1) The weight of empty petri dish is taken by using weighing machine and consider the weight as X . 

2) In the tared petri dish 2gm of Starch of which moisture content value to be determined, is taken slowly with spatula to get the desired weight. 

3) Weight of empty petri dish with starch is taken again and noted as (X+2). 

4) The petri dish containing starch is placed into the hot air oven to heat it at 115℃ by setting the temperature of hot air oven with the help of temperature setting node, so that the moisture present inside the crude drug get evaporated. 

5) After 1 hour switch off the hot air oven, and petri dish containing starch is removed from hot air oven.

6) The petri dish containing starch is placed in a close container to room temperature to prevent the starch from reabsorbing the moisture from the surrounding during cooling. 

7) After cooling again the dish containing the drug is weighed and the value is considered as Y. 

8) The ideal condition must be [Y< X+2] 

9) Repeat the procedure several times and check the weight in half an hour interval, until two same successive reading or do not differ by more than 5 mg. 

10) From the values the moisture content is calculated by subtracting the weight of the empty petri dish with a drug before drying with the weight of the empty Petri plate with drug after drying. 

11) Percentage moisture content value or mg/g moisture value is calculated. 





Observation:-

Weight of the empty petri dish = 48.43gm 

Weight if the petri dish with 2gm of sample crude drug = 50.43gm

 After 1hour of drying, weight of the total petri dish containing sample = 50.32gm

 After 30minutes of drying, weight of the total petri dish containing sample = 50.20gm

 So here, the constitutive reading is 50.20gm





Calculation:- 

Moisture content = ( petri dish with drug before drying – petri dish with drug after drying)

 Wt. of petri dish = 48.43 gm 

Wt. of petri dish + starch = (48.43+2) gm. = 50.43 gm. 

After drying the wt. is 50.20 gm. 

Moisture content = (50.43 – 50.20) gm. = .23 gm. 

Percentage of moisture content = ( .23 x 100 )/2 = 11.5 % 

Moisture content in mg = 230 mg 

So , In 1 gm. 230/ 2 mg/g of sample = 115 mg/g of sample 

Conclusion:-

        The moisture content of drug should be minimized to prevent decomposition of crude drug either due to chemical change or microbial contamination. So the moisture content determination plays a very important role in quality control test of crude drug. In this experiment we took starch as crude drug and we evaluated it’s moisture content in percentage and mg/g. 


REFERENCES:-

1. GURU NANAK INSTITUTE OF PHARMACEUTICAL SCIENCE AND TECHNOLOGY LAB EXPERIMENT

2. Quality control methods for medicinal plants material by W.H.O. Guidelines: 45