The concept of pratinidhi dravyas is need of todays pharmaceutical industry. Pratinidhi drug is substitute drug in absence of an original drug (abhav dravya). In Bhavprakash list of pratinidhi dravya is given in mishra varga prakaran but in Yog ratnakar abhav varga is mentioned separately. Substitution is based on Ayurvedaic principles that both the drugs (abhav and pratinidhi) should posses similar guna and therapeutic activities.

The concept of pratinidhi dravya overcomes the problem of unavailability of some drugs, which are used in medicinal formulations. In Ayurveda, medicines are prepared by using plants, minerals, some animal products, metals and gems. Majority of medicines are prepared by using medicinal plants but now a day medicinal plants which are required for herbal industry facing shortage due to deforestation , loss on habitat , over exploitation , extinction of rare plants , indiscriminate harvesting impairing the availability of raw drugs . In case of precious stones, gems they are also not easily available and they are too expensive. So to overcome these problem substitutions of these gems (diamond) and metals (gold) are available. Substitutes are intentionally selected and utilize rationally to achieve the desired effect. By using substitutes in medicinal formulation we get quality herbal formulations with economic feasibility.
 
The list of pratinidhi dravyas is given below:

Minerals & Metals

Vanaspati Dravya

Ashtavarga Dravya

Abhav Dravya For Aahariya Dravya

The most important criteria of pratinidhi dravya seems to be similar in indications and their therapeutical activities. To select a proper substitute, one has not only seek overall similarities of guna (rasapanchak) but also test its therapeutic efficacy clinically.  According to Ayurveda sar sangraha, the formulations contains one main drug and others supportive drugs. The formulation cannot be formed without the main drug hence, main drug cannot be replaced by any other drug.  So list of abhav dravya is given for supportive drugs in the formulation. Some examples of main drugs and supportive drugs in the formulation are given below:

So as per the guidelines, pratinidhi dravya for draksha, shankha and kasturi should not used for the preparation of main drug formulation.

This article is published under the guidence of HOD Vd. Kalyani Jadhav and Guide Vd.Kavita S Deshmukh. Ssam Hadapsar Pune 28.