Rasa Śāstra is a well-established branch of Ayurveda serving humanity with its unique heritage of drugs derived from mineral, metal and animal origin combined with certain herbs. Metals and minerals are extracted from the earth crust, so the drugs come in contact with impurities, heterogeneous materials, toxic substance and unwanted qualities. To remove all such unwanted material and to increase the potency; an exclusive procedure - Śodhana is indicated in classics. Wide range of Śodhana methods are prescribed for metals, minerals and other substances in different classics of Rasa Śāstra. These methods not only eliminate unwanted principles from the raw material, make the material feasible for further processing but also help in enhancing their therapeutic potentials. These processes are individualized in term of material media, method etc.
Svarṇa Mākṣika (SM) is an important mineral used for medicinal purposes since saṁhitā period in many diseases in the form of Bhasma. It is one of the major ingredients in popular formulations like Candraprabhā vaṭi, Vātagajānkuśa rasa, Śvāsakāsa cintāmani rasa, prabhākara vaṭi  etc. Ancient Rasa Scholars have developed number of processing methods for a single substance by which crude form of drug can convert into highly potent therapeutic agent. Till date no published review work is found on the different Śodhana procedures of Svarṇa Mākṣika. This work may prove a torch bearer for future research work on Svarṇa Mākṣika.
In this review, information from various texts belonging from 7th AD to 20th AD has been compiled. The books referred in this attempt are Rasendramangala, Rasahridayatantra, Rasarṇāva, Rasendra cuḍāmani, Ayurveda prakāśa, Śārangadhara saṁhitā, Rasa ratnākara, Rasaprakāśa sudhākara, Rasa ratna sammuchaya, Rasapaddhati, Ᾱnanda kanda, Rasa cintāmani, Rasamanjari, Rasa sanketa kalikā, Rasendra cintāmaṇi, Rasendra sāra saṁgraha, Rasa kaumudi, Rasa kāmadhenu, Yoga tarangiṇi, Yogaratnākara, Arka prakāśa, Brihat rasa rāja suaṁdara, Rasarāja mahodadhi, Rasāyanasāra, Rasa jalanidhi, Siddha bheṣaja maṇimālā, Raṣopaniśata, Rasāmitram Sahasrayogam, Rasatarangiṇi, Rasendra saṁbhava, Anupāna maṁjari, Abhinava navajeevaniyama, Rasa dipikā, Rasa tantrasāra and siddha yoga saṁgraha, Rasāyana sāra. Svarṇa Mākṣika Śodhana in the above mentioned texts of Rasa Śāstra are analyzed with respect to liquid media and involved principles etc.
Śodhana is a procedure to be adopted to remove possible impurities from Rasa Dravya and other material of such manner. Besides this, the procedure is aimed to change the nature of the substance (Physical as well as pharmacological aspects). It is a pre-requisite procedure for all substances (Rasa and Viṣa Dravya etc.) that may have a bad effect in their raw form over body. As per Ayurvedic texts; all metals, minerals, poisonous herbs are to be processed through this specific procedure. General procedures, drugs used for Śodhana process and their probable impacts are well explored in Ayurvedic classics. Selection of particular method and media for Śodhana has been left on physician with application of Yukti (Rationale – logical reasoning). The changes made by Śodhana in nature of drug can be preliminarily and easily perceived at pharmacognostic as well as chemical levels, however its utility will be majorly dependent on therapeutic actions. Different methods of Śodhana also play an important role in altering pharmaceutical[51,52] analytical[53,54] toxicological pharmacological[56,57] and therapeutic aspects of a metal/mineral or its formulations. There is a separate book named “Ᾱyurvediya auṣadhi dravya Śodhana Vidhi” exploring logical selection of various methods of Dravya Śodhana, with details of changes after Śodhana.
Need of Svarṇa Mākṣika Śodhana
A drug can be panacea or poison. A drug fulfilling the criterion of a standard drug will always become panacea provided, if it is used properly. On the other hand, a poorly prepared or manufactured drug however used skillfully, will always prove to be a poison. Svarṇa Mākṣika (SM) is the most abundant copper containing mineral with nearly equal part of copper (34.5%), Iron (30%), Sulphur (35%) along with trace elements like Ag, Au, As, Se, Sn, Zn etc. As per API, SM in ore form should contain not less than 5 % Copper, 20 % Iron and 12% Sulphur which matches with several analytical reports.[47,62] If raw SM is used without Śodhana, it will cause untoward effects like Agnimāndya (dyspepsia), Vāaṁti (vomiting), Viṣṭhaṁbha (failure to pass flatus), Vibaṁdha (constipation), Vātaprakopa in koṣṭha, Krimi (worm infestation), Halimaka (fulminant hepatic failure), Gaṁḍamālā (hypo or hyperthyroidism), Vraṇa (ulcers), Kuṣṭha (skin disorders), Netraroga (eye diseases), Daurbalya (generalized weakness), Kṣaya (emaciation), Balanāśa (loss of strength) and even Maraṇa (death).[11,36]Most of the symptoms mentioned in classics resembles with acute or chronic copper toxicity. To avoid these manifestations, one need to process it before its application in therapeutics.
The media used in the process of Śodhana has very important role in either breaking down or destroying the chemical constituents that are not required. The heat treatment through constant boiling of the drug in a particular media for a particular duration has a role in modification of the chemical constituents etc. Studies have shown that the toxic constituents are transferred into media rendering the drug non-toxic. Media has definitely an important role in making a drug to act without causing any side effects.
Careful review of available classical texts to compile Śodhana procedures of SM revealed multiple methods that were categorized according to the involved individual and multiple media used. Twenty six methods of SM Śodhana are described in classics on Rasashastra that can be categorized into five basic methods like Swedana, Bharjana, Nirvāpa, Mardana and Puṭapāka among which Swedana method is found most frequently mentioned (Table 1).
|2||Bharjana (frying in pan)||5|
|5||Bhavana / Mardana (grinding)||2|
More than 19 classics of Rasa Śāstra have described details about SM Śodhana. Seven individual liquids are found utilized for Śodhana. Among them the frequency of use of Kadali kanda Svarasa in Rasa classics is found highest (5 times) followed by Triphalā Kvātha (4 times). Compiled data also revealed that, total 19 multiple liquid media are used for SM Śodhana (Table 2).
Daḍima (Punica granatum Linn) tvak or Kulatha (Dolichos biflorus Linn.) Kvātha are mentioned as an antidote of Svarṇa Mākṣika toxicity due to over-dosage or usage without purification procedure. Among them Kulatha Kvātha frequently used by many seers in Śodhana procedure of SM. Nimbu Svarasa as liquid media by Bharjana method advised in Rasatarangiṇi is recommended by Ayurvedic Formulary of India (AFI), which is followed by most of the research scholars.[66-68] Majority of the texts prefers using Lohapātra (Iron vessel) in the Śodhana procedure that was emphasized in AFI too. SM Śodhana by Nirvāpa procedure is advised to be repeated for 21 times, while in Puṭapāka method 1 to 6 repeated Puta are given. One hour to three days Swedana procedure whereas one to three days Bharjana procedure are also advised for SM Śodhana (Table 2). Media advocate for SM Śodhana by Nirvāpa method is nothing but the Samanya Śodhana procedure of metals and minerals. Puṭapāka method is used by various Acharya for SM Śodhana but text Ᾱnandakanda admits this as Māraṇa of SM. Ᾱnandakanda also mentioned use of metal i.e. Nāga (lead) as a Śodhana media for Śodhana of another mineral i.e. SM. Three parts of SM and one part of each Nāga and Ṭankaṇa are taken in an iron vessel and roasted in Mātulunga or Jambiri svarasa till SM achieves Tāmra varṇa (reddish brown). SM Bhasma preceded with this method of Śodhana will contain whole of the added Nāga and roasted Ṭankaṇa too. Although not mentioned but it is advisable to use Śodhita or Jārita Nāga in this process. Aśuddha SM and Saindhava lavaṇa are taken in powdered form and subjected to tīkṣṇāgni (intense heat) in an iron pan with Nimbu Svarasa for Śodhana. This method is mentioned by majority of Rasācārya that is commonly used. In classics, it is clearly mentioned that after completion of Śodhana the colour of SM will be changed to Tāmra varṇa  or Śodhana procedure should be carried till SM turns to Lohita varṇa (red colour). Multiple physicochemical, structural changes in different common categories of Śodhana processes of Svarṇa Mākṣika (Chalcopyrite) may take place which are summarized in Table 3.
AK - Ᾱnanda kanda, AP - Ayurveda prakāśa, BRRS - Brihat rasa rāja suaṁdara, RCh - Rasendra cuḍāmani, RChi - Rasendra cintāmani, RJN - Rasa jalanidhi, RMan - Rasamanjari, RMri - Rasāmitram, RN - Rasarṇāva, RP - Rasa Paddhati, RPS - Rasa prakāśa sudhākara, RRat- Rasa ratnākara, RRS- Rasa ratnasamuchaya, RS - Rasāyana sāra, RSS - Rasendra sāra saṁgraha, RT - Rasatarangiṇi, RTS & SPS - Rasa tantrasāra and siddha yoga saṁgraha, ShS - Śārangadhara saṁhitā, YT - Yoga tarangiṇi.
|Procedure||General Method||Probable physicochemical changes [43-48]|
|Swedana (boiling)||In this process, SM is boiled in prescribed liquid media through Dola Yantra method for at least three hours. The impurities which are soluble only in boiling hot acidic or alkaline liquids could be removed through this process.||Formation of organo-inorganic compounds.|
Leaching of metal contents in liquid media.
|Bharjana (frying in pan)||Here the SM is place into the iron pan and subjected to heating with or without adding any material/ liquid while heating. In this process constant stirring of the material is done till the added liquid is evaporated and the material is converted into red.||Sulphation.|
Sulphatizing (formation of metallic sulphates).
Cloridizing (Formation of flux with salts).
Desulphuration (reduction in sulphur content and resulting in increase of copper, iron and other trace elemental content).
Sulphation followed by desulphuration, formation of CuSO4.
Formation of ferrites.
Oxidation of metals (increase in oxygen content).
Removal of undesirable elements like
|Nirvapa (quenching)||In this process, small crystals of Svarṇa Mākṣika are heated up to red hot and dipped into the various types of cold liquids (oily, acidic or alkaline types). This heating and dipping is repeated till complete cessation of sulphur fumes||Desulphuration,|
Annealing of Iron, copper (Isothermal decomposition and Phase interchange) Removal of undesirable elements like
Formation of little quantity of oxides, sulphides, sulphates of metals.
|Puta (incineration)||Svarṇa Mākṣika is ground with prescribed liquid media till it attains semisolid paste like consistency. Then chakrikas (small round pellets) are made and dried. After drying these chakrikas are kept in sharava samputa (earthen plate) and sealed with the help of cloth smeared with multani matti. This is subjected to putapaka.||Desulphuration,|
Oxidation of metals (Copper oxide, Fe2O3, SiO2),
Formation of new polysulfides in lesser amount (CuS, FeS).
Formation of sulphates.
Reduction of particle size.
Physical/structural changes (Regularization of loss of crystallinity).
Uniform arrangement of particles). Removal of undesirable elements like
Arsenic, Antimony, Carburising.
|Bhavana / Mardana (grinding)||In this process SM is triturated with the paste of certain herbs and other drugs such as salts, alkalies, carths and some vegetable extractives having acidic/ alkaline reactions or with acidic juices and/or fluids for a specified period.||Reduction of particle size|
Formation of organo-inorganic compounds.
Maximum Śodhana methods i.e. 13 were described by Ᾱcharya Bhudeva Mukharji in Rasajalanidhi. Compiled data revealed that, at least 34 (Plant origin - 24, Animal origin - 5, Mineral origin - 5) varieties of liquid media as Śodhana dravya are mentioned in classics (Table 4).
Śodhana is unique and distinct pharmaceutical procedure in Ayurvedic Pharmaceutics, with potential to influence physicochemical, toxicological, pharmacological and therapeutic profile of Svarṇa Mākṣika and thereby useful in increasing safety and optimizing desirable efficacy of Svarṇa Mākṣika. Physicochemical changes may occur depending upon the selection of the Śodhana media such as particle size reduction, variation in elemental composition and addition as well as deletion of minor elements from the raw material.