Dosage form and Formulation

Tablet,capsules,injection are different dosage forms.Depending upon the stability of the drug ,its absorption in the body etc.drug is formulated in one of these forms.

Dosage forms contain 2 components 

1.Drug

2.Excipients

Example: 
Crocin(500mg) Tablet contains 500mg(strenght) of drug ie Paracetamol/acetaminophen ,but when you weight the tablet its weight will be  500-600mg,this extra 100mg is because of excipients .

 Formulation is not always disclosed by the company.
If you check on Benadryl cough syrup bottle you will find 
EACH 5 ml contains
Diphenhydramine HCl    14.08mg
Ammonium chloride      138mg
Sodium citrate                 57.03mg
Ethanol                            .2625ml
colours: carmoisine,sunset yellow ,FCF,Erythrosine,Caramel I.P

This can give you a rough idea about formulation .
In case of Benadryl ,Diphenhydramine HCl is the Drug and all the other substances are excipients.The quantity of excipients can be more than that of drug .

Crocin(Glaxo Smithkline) and Benadryl (Johnson & Johnson) are proprietary names(trade names) under which a manufacturer  markets its product.The drug in crocin is Paracetamol/amphetamine and in Benadryl is Diphenhydramine HCl.

Tylenol also contains 500mg paracetamol .The brand name "Tylenol" is owned by McNeil Consumer Healthcare, a subsidiary of Johnson & Johnson.