What is Patent Medicine?
Chinese patent medicines generally consist of extracted condensed pills called teapills, which are usually small, spherical, and black, appearing like black pearls. They are called teapills because the herbs are cooked into an herbal tea to make the pills. Honey or water pills made from ground raw herbs are also a popular format in China, and tend to be bigger and slightly to significantly softer than teapills.
Modern teapills are created from herbs extracted in stainless steel extractors to create either a water decoction or water-alcohol decoction, depending on the herbs used. They are extracted at a low temperature (below 100 degrees Celsius) to preserve essential ingredients. The extracted liquid is then further condensed and a bit of raw herb powder from one of the herbal ingredients is mixed in to form an herbal dough. This dough is then machine cut into tiny pieces, a small amount of excipients are added for a smooth and consistent exterior, and they are spun into pills.
Honey pills and water pills have been made since ancient times by combining several dried herbs and other ingredients, which are ground into a powder, mixed with a binder and traditionally formed into pills by hand. Modern honey or water pills are formed into pills by machine. The binder is traditionally honey for honey pills. For water pills the binder may simply be water, or may include another binder, such as molasses. Modern manufacturers still produce many patent formulas as honey or water pills, such as Wuji Baifeng Wan, a popular honey pill formula to "nourish qi and blood", to strengthen the body.
Patents may come in other forms such as dripping pills, liquids, syrups, powders, granules, instant teas, and capsules. Companies make Chinese patent medicines both within and outside China.
Like other patent medicines, they are not patented in the traditional sense of the word. No one has exclusive rights to the formula. Instead, "patent" refers to the standardization of the formula.
In China, all Chinese patent medicines of the same name have the same proportions of ingredients, and are manufactured in accordance with the PRC Pharmacopoeia's monograph on that particular formula, which is mandated by Chinese law. Each monograph details the exact herbal ingredients that make up the patent formula, usually accompanied by the specific tests that should be used for correct herb identification, such as thin layer chromatography (TLC) or high performance liquid chromatography (HPLC), the percentage of each ingredient, and specific cautions and contraindications. The monograph also details the manufacturing methods that must be followed, how to process and cook the herbs, often including specific requirements for finished product testing including authenticating and assessing the potency of the formula with active ingredient markers where known, as well as testing for dissolution time and content uniformity. All good manufacturing practice (GMP) certified factories must also test for heavy metal levels and microbials for all patent medicines they produce.
However, many patents do not list all ingredients, presumably to protect the secrecy of the formula. An example of this is Yunnan Baiyao, a popular formula used to stop bleeding, whose ingredients have never been revealed. This is an acceptable practice in China, where no other protection exists to protect family or "secret" Chinese herbal formulas.
In western countries, there is considerable variation of ingredients and in the proportions of ingredients in products sharing the same name. This is because the Chinese government allows foreign companies to apply for modifications of patent formulas to be sold outside of China. For example, Hebei brand Lifei pills contain Kadsura (feng sha teng) and Morus (sang ye), whereas Plum Flower brand Li Fei Pian contains Schizandra (we wei zi) and Gecko (ge jie) instead. Another example is Qing Qi Hua Tan Wan. The Lanzou brand uses Citrus (ju hong). The Lanzhou Foci Min Shan brand and the Plum Flower brand do not, but use Ginger (sheng jiang).Extract from http://en.wikipedia.org/wiki/Chinese_patent_medicine