Quality in Tableting "The MediHerb" Way

Over the past five years tablets have established a vital role in modern phytotherapy. Provided they retain the full potency of the galenicals, they represent a patient-friendly form of therapy which can vastly enhance compliance. Many experienced herbalists who are MediHerb customers rely on our tablet range for poorly-compliant patients and also to treat difficult or complex cases where just a liquid formulation may not be sufficient treatment on its own. In addition, several herbs are best given in tablet form in order to conveniently achieve the necessary effective dose (as established in clinical trials eg Tribulus) or to avoid excessive amounts of ethanol (eg Boswellia).


It’s a different way to make tablets – which is why we call it the MediHerb way. So what do we do that is different?


Firstly and perhaps most importantly, our unique Cold Percolation 1:2 liquid extracts are used in the manufacture of the MediHerb tablet range which means they are very potent and equivalent to the original galenical liquid extract. Many other herbal tablets/capsules are made from powdered dried herbs or poor quality dried extracts which means they are far less potent or potentially adulterated.


Secondly, our tablet production process has been the focus of extensive research and development to ensure that the finished tablet is as efficacious as the liquid extract, and that the full phytochemical profile has been retained.


From our research, we have found that the optimal method of herb processing involves the evaporation of the ethanol and water at low temperatures under vacuum. This important step minimises the exposure of the delicate chemicals in the herbal matrix to the damaging effects of heat and oxidation. The MediHerb tableting process takes this one step further to actually specify the optimal parameters employed during the evaporation and drying processes for each of the active constituents of the final tablet.


While the MediHerb cold percolation 1:2 liquid extracts are used for manufacturing our tablet range, there are on occasion some high quality extracts available from specialist extract manufacturers. In this case, we still apply the MediHerb stringent quality analysis at every step of the purchasing and manufacturing process to ensure our product is of superior quality. For example, there are many St John’s Wort extracts available for purchase but of varying quality, MediHerb would only consider purchasing an extract if it exceeded our quality standards.


As with the MediHerb liquid herbal extracts, our tablets are manufactured to pharmaceutical standards. Each batch of tablets is tested for disintegration, friability, weight uniformity, and where relevant, for active constituents. However, it is only by ongoing research and control of all stages of the manufacturing process from




that MediHerb has been able to produce superior tablet formulations, producing tablets with high active constituents that still comply to pharmaceutical standards.


MediHerb tablets must legally disintegrate in less than 30 minutes. This means that even patients with poor digestion can quickly and easily absorb our tablets for maximum efficacy.


MediHerb's Tableting Process Using Our Liquid Extracts


Tableting Web2



Full Spectrum Extracts Mean Greater Efficacy but Lower Herb Equivalents per Tablet

Practitioners often compare herb equivalence on tablet labels in an effort to gauge the most effective formula for their patients. However, herb equivalence can be quite misleading when comparing potency of products.


The process of standardisation can encourage an approach to manufacturing herbal extracts that only focuses on the one active constituent or marker compound whilst ignoring the remaining phytochemical profile of the herb. As we know, herbs contain a wide variety of phytochemicals in an inert matrix of vegetable matter (eg cellulose). When a herb is extracted with a solvent, the resulting phytochemicals that are extracted will depend upon the type of solvent employed.


Generally the insoluble matrix components will be left behind. By using a combination of solvents, one can very selectively extract an individual compound or one group of compounds. However this begs the question as to whether the process produces a herbal product or a product bordering on a pharmaceutical, because the phytochemical profile of the raw herb and the ratio of active constituents to marker compounds can be greatly altered.


One example of this is the use of Scutellaria baicalensis (Baical Skullcap) extracts, which only contain baicalin and do not contain any of the other 20 or more of its flavonoid constituents. These other constituents are typical of Baical Skullcap, the most important of these being wogonin-7-O-glucuronide, oroxylin A-7-O-glucuronide, baicalein, wogonin and oroxylin A. Sources of Baical Skullcap extract used in some herbal tablets contain greater than 95% baicalin, this means that less than 5% of the material is something other than baicalin. This is no longer a herbal extract and is rather a purified phytochemical (refer to the HPLC trace of Baical Skullcap and baicalin). These extracts are typically claimed to be a 20:1 dry extract and as such 500 mg of this extract placed into a tablet means the manufacturer or marketer of the product would be able to claim (20 x 500 mg) 10,000 mg of Scutellaria baicalensis dry root.


"All tablets must disintegrate in the stomach in under 30 minutes
(with the exception of enteric-coated tablets)"


In contrast, the extract produced by extraction of Baical Skullcap with 45% ethanol contains a very high level of solids material and a full complement of the many flavonoid components. As a result, a dry extract made from this liquid can only be manufactured with a 3:1 dry extract concentration factor. Adding 500 mg of this MediHerb extract into a tablet means we can only claim (3 x 500 mg) 1500 mg of Scutellaria baicalensis dry root.


What was left out in these extract to produce this product?



Baical Skullcap HPLC


This product would not pass the criteria set by MediHerb, as it does not contain the full phytochemical profile expected for Baical Skullcap.