Standards are living documents, which reflect science, technology and systems. To maintain their value, they should be first decided, achieved, set and then periodically validated to maintain their reproducibility. In this study an attempt has been made to validate and develop standard manufacturing procedure of Samanya and Vishesha Shodhana of Tamra so that these observations can be reproducible on large scale production too.

Keyword : Bhasma, Tamra, Shodhana, Gomutra, validation

Introduction :

Validation literally means to render the process valid after substantiating known process with a scientific ground in order to deliver a particular product. On other hand, standardization is a process resulting from a consensus based on scientific findings, obtained by parties most affected by it.[1] But the term validation is used more recently replacing standardization and is more globally accepted. For the pharmaceutical processing and formulations contributed by the Rasa Classics, validation stands at the far end of the road, with many milestones to be crossed by bridging innumerable gaps. As for the classics and for their uses, the formulations stand already standardized. What actually meant by validation is substantiation of the existing processes. Once the process is established to be cogent enough to yield persistently unvarying results, that process is said to be valid. The main use of process validation is that it yields the same result (reproducible) as the skilled, even if performed by an unskilled person, and it also helps in batch wise record maintenance for elaborate and lengthy processes.

A wide range of Shodhana (purification and/or detoxification) methods are prescribed for metals, minerals, and other substances in different classics of Rasashastra. These methods not only detoxify the raw material by chemical transformations but also enhance their therapeutic potentials.[2] In pharmaceutical viewpoint this procedure is performed to make the material feasible for further processing. In case of metals and minerals, for Samanya (general) Shodhana, mainly the procedure of Nirvapa (heating and quenching) in different media is advocated in various classics. Whereas for Vishesha (specific) Shodhana different methods like Swedana (boiling), Nirvapa in specific medium, etc have mentioned. Tamra (copper) is one of such metals which are being used in Rasashastra for various purposes like transformation of lower metals to higher ones (Lohasiddhi), for living disease free long life (Dehasiddhi), sublimation of mercury (Urdhwapatana Samskara of Parada), therapeutics etc. But before using in therapeutics, ancient Acharyas have deliberately focused on its toxic nature.[3] They have warned that it should not be used in Ashodhita (unpurified) or Apakwa (improperly processed) form and has equated these with poison because of its hazardous effects on the body and due emphasis have been given to its Shodhana procedure.[4]

Though the process of validation of such a versatile subject of Rasashastra is like harnessing a wild horse, the trend of setting standards for Ayurvedic drugs is fast approaching. But it can be so done only by validating the existing processes. In this study, an attempt has been made to validate Samanya and Vishesha Shodhana procedures of Tamra and develop their standard manufacturing procedure.

Materials and Methods :

Procurement of basic raw material: Tamra wire of 0.5 mm diameter was procured from an electrician. There was no coating over the wire. This wire was converted to thin sheet of 36 guage thickness by passing it through a roller press. The sheet was then converted to pieces of 1×1 cm. Tila Taila [Sesamum indicum Linn. (Oil)], Tandula (Oryza sativum Linn.) and Kulattha (seeds of Dolichos biflorus Linn.) were procured from local market. Gomutra (cow urine) was collected from local cow shed.

For the purpose of validation, each step of the procedure of each unit operation was considered as an independent procedure and a pharmaceutical proforma was prepared to record minute facts and observations regarding the procedure. For fixing the standards, minimum of three readings of each step were taken.

Pharmaceutical processing like preparation of Takra (buttermilk) [5], Aranala (sour gruel) [6], Kulattha Kwatha (decoction) [7], Samanya Shodhana [8], and Vishesha Shodhana[9] of Tamra were considered as unit operative procedures and were carried out as per classical references.

Samanya Shodhana of Tamra : It was done by the procedure of Nirvapa (heating and quenching) sequentially in following media (7 times in each): Tila Taila, Takra, Gomutra, Aranala, and Kulattha Kwatha [Fig 1]. Equipments used for this purpose were: Gas burner, iron pan, iron ladle, iron rod, stainless steel vessels (2), spatula, measuring mug, weighing machine, pyrometer, and thermometer (3600C).

Procedure : Raw Tamra flakes were taken in iron pan and was heated on gas stove up to red hot and quenched in specific liquid media, which was taken in a stainless steel vessel. After cooling Tamra was taken out from the vessel, again taken in iron pan and heated and quenched. The process was repeated for 7 times in each media. Every time fresh and gravimetrically same amount of media was taken. Temperature of iron pan, and Tamra during red hot state was noted. Weight of Tamra, volume of media, time taken for each process etc were noted at each time. All the data was recorded in the pharmaceutical proforma. The same procedure was followed for other batches.

Vishesha Shodhana of Tamra : Samanya Shodhita Tamra was kept in pottali prepared from cotton cloth. An iron rod was introduced at the tip of the pottali and it was hanged in steel vessel and 2.5 l Gomutra was added to dip it completely [Fig 2]. Swedana process was done for 3 hours. Extra Gomutra was added to maintain sufficient quantity to dip the pottali. After 3 hours, pottali was taken out and Tamra was washed with warm water and dried. Temperature of Gomutra was recorded and maintained during whole procedure.

Analysis of the samples : Estimation of copper and iron content in percentage was carried out in the samples of raw Tamra, Samanya and Vishesha Shodhita Tamra.[10] Different media used for the purpose of Samanya and Vishesha Shodhana were subjected to physico-chemical analytical parameters like determination of pH[11], specific gravity[12], refractive index[13], total solid contents[14] etc . For this purpose, samples of before and after Shodhana were used.

Observations :

Various observations and average values during the Takra, Aranala and Kulattha Kwatha preparation are described in Tables 1, 2 and 3 respectively. The results and findings of Samanya and Vishesha Shodhana are described in Tables 4, 5, 6 and 7. The variation in copper percentage and change in physico-chemical values of media have been presented in Tables 8 and 9.

In Samanya Shodhana, after seven Nirvapa in Tila Taila, reddish color of Tamra became black and its metallic luster was lost. Some part of Tamra got powdered and weight of Tamra was found increased. Though it was washed with hot water some oil was still sticking to it. Color of Tila Taila became light yellow to light brown and it became more viscid. Oil caught fire with dense fumes during quenching. A pungent smell and a rush of black fumes were observed after quenching. After Shodhana in Takra, Tamra caught fire during first heating, but did not catch in next heating. Color of Tamra became black to blackish gray. Some part of Tamra was converted to coarse powder form. Some cracks were observed on the surface of Tamra flakes. After quenching, Takra started to boil and it separated in solid and liquid parts during quenching and solid part got settled down. Fine particles of Tamra which were suspended were found difficult to collect due to thickness of Takra.

During Shodhana in Gomutra, color of Tamra became blackish gray to brown; some Tamra flakes were broken into small pieces and some of it’s became coarse powder. Color of Gomutra became yellowish to brownish after seven Nirvapa. A pungent smell was perceived during quenching. During Shodhana in Arnal, color of Tamra became brown to blackish brown; flakes of Tamra became more brittle and were transformed to more coarse powder form. Color of Arnala became yellowish to brownish and became more viscid after seven quenching. A specific burning smell was coming out during quenching. After Shodhana in Kulattha Kwatha, color of Tamra became blackish brown to deep brown; it became more in coarse powder form. Color of Kulattha Kwatha became brown to bluish brown and its consistency became thicker. A specific obnoxious smell was coming out during quenching. In Vishesha Shodhana, after first 20 minutes, froth was observed in Gomutra but it subsided after 5 minutes. During Swedana, color of Gomutra turned to blackish green with a strong irritating smell. Blackish color of Tamra changed to greenish after Swedana. [Fig 3]

Discussion :

Shodhana is a procedure of elimination of Dosha (impurity/toxicity/flaw) from the drug.[15] The term Dosha indicates not only impurities but also all that which makes the drug unsuitable for further process or therapeutic use. In case of metals and minerals, it is a physico-chemical and therapeutic transformation of a substance making it feasible for the next process (Marana) or directly for therapeutic use.

Nepalaka Tamra is to be taken for the use of therapeutic purpose and it should have the properties like Snigdha (smooth), Mridu (soft), and Shonam (blood red in color), Ghanaghatakshamam (spreads on hammering without cracks), Guru (heavy) and Nirvikaram (not affected by air/water). [16] Procured Tamra wire was satisfying these criteria and percentage of copper in it was 99.8, thus it was authenticated.

During Samanya Shodhana procedure, the metallic form of Tamra gets converted slowly to compound form (CuO in this case) [17]; thus its heat conductivity is reduced which is the reason why Tamra flakes take more time to become red hot as the Shodhana procedure advances [Table 4]. Repeated heating and quenching in specific media in this specific order (pH: acidic, acidic, basic, acidic and basic) disrupts the compression-tension equilibrium in the internal structure of Tamra which leads to cracks on its surface. (Griffith theory [18], Stress corrosion theory [19], and Theory of thermal expansion [20]) As a result of this, some part is converted to coarse and some in fine powder. After each quenching, this powder was found as sediment in media. Since Aranala falls under the strong acidic category and also has Tikshna (penetrating) property[21], maximum amount of sediment was found in Arnala medium (Table 5). Due to thicker consistency of Takra medium, sediment was not observed but black particles were seen suspended in it which was difficult to collect. Due to adherence of Tila Taila, 1.42 % weight gain was observed in spite of weight loss after Nirvapa in Taila medium. Use of acidic and alkaline media may cause removal of acid and alkali soluble impurities from the metal.[22]

In Vishesha Shodhana, components of Gomutra may pierce through the micropores and cracks created during Samanya Shodhana and may produce the required change specific to Tamra for further process. In this process, cuprammonium ion [Cu(NH3)4], a chemical complex which is water-soluble may have formed due to the reaction between copper and ammonia from Gomutra.[23] This complex gets washed away during washing with hot water. This may be the reason behind the weight loss after this procedure.

In physico-chemical analysis of media no major changes were observed. Total solid content of all the media after Shodhana procedure were increased slightly just because of the fine particles of Tamra which came into it during Shodhana procedure. Further analysis like atomic absorption spectrometry of these media is also possible to assess the amount of copper in them at different stages of Shodhana.

Raw Tamra quantitatively contained 99.87% w/w of copper which indicates the high purity material. After Samanya Shodhana the copper content was found decreased whereas iron content was increased. In Vishesha Shodhana, copper percentage was further decreased whereas iron was increased [Table 9]. During red hot state copper is decomposed to cupric oxide (CuO) on its surface [24] and it is well known fact that inorganic oxides are only soluble in organic solvents. This shows the scientific approach of ancient seers behind the use of different organic solvents for Nirvapa. Since the iron ladle was used to perform the procedure, percentage of iron was found increased after the process because iron also reacts with atmospheric oxygen or steam when heated to red hot, to form ferroso-ferric oxide (Fe3O4) [25] and this oxide gets mixed with copper. One of the analytical studies, X-Ray diffraction showed that when the raw Tamra was converted to Vishesha Shodhita Tamra by series of Samanya Shodhana procedure there is change in cell type. Its hexagonal cell type is converted into monoclinic cell type after Vishesha Shodhana, which indicates the definite role of Shodhana at micron level. [25]

Conclusions:

Nirvapa is the commonest method of Samanya Shodhana of metals including Tamra. For 500 g of Tamra, on an average 3500 ml of each media is required along with 7.8 % of weight loss in this process whereas for Vishesha Shodhana of 452.33 g, 3000 ml of Gomutra is required along with 2.14% of weight loss. This whole procedure makes Tamra more brittle and leads to partial conversion into coarse powder form. Data obtained from the present study is reproducible. To avoid the batch to batch variation, this SMP may be applied to large scale. The values of copper and iron percentage in different samples can be taken for quality assurance.

Tables :

Table 1: D etails of Takra preparation and observations

Table 2: Details of Aranal preparation and observations

Table 3: Details of Kulattha Kwatha preparation and observations

Table 4: Average values of each Nirvapa during Samanya Shodhana

Table 5: Weight of sediment after 7 Nirvapas in each media

nm = not measurable

Table 6: Change in weight of Tamra after 7 Nirvapas in each media

Batch no.	Ashuddha Tamra taken for Shodhana (g)	Wt. of Tamra / after 7 Nirvapas (g)					Shuddha Tamra obtained (g)	Wt. loss (g)	Wt. loss (%)
		Tila Taila	Takra	Gomutra	Aranala	Kulattha Kwatha
1	500.0	514.1	488.9	478.4	465.4	460.6	460.62	39.38	7.8
2	500.0	508.8	485.7	475.9	466.5	462.6	462.75	37.25	7.4
3	500.0	518.7	483.8	472.6	462.8	458.9	458.92	41.08	8.2
Ave.	500.0	513.	486.2	475.7	464.9	460.8	460.76	39.24	7.8

Table 7: Loss in weight of Tamra after Vishesha Shodhana

Table 8: Analysis of liquid media before and after Shodhana of Tamra

Table 9: Percentage of copper and iron in raw Tamra, Samanya and Vishesha Shodhita Tamra

* Ph.D. Scholar, Department of Rasashastra and Bhaishajya Kalpana including drug research, IPGTRA, Gujrat Ayurved University, Jamnagar
** Professor and Head, Department of Rasashastra and Bhaishajya Kalpana including drug research, IPGTRA, Gujrat Ayurved University, Jamnagar

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