It is frequently desirable to prescribe pharmaceutical dosage forms containing at least two different drugs for obtaining the pharmacological benefits of each drug. The coadministration of certain drugs is prescribed often in fixed ratios for several reasons. For example, for drugs that have the same therapeutic effect but act mechanistically different on the body, such combinations may have the added therapeutic effect of both agents but less side effects, or the drugs may act synergistically and create a larger than additive effect. Also, drug combinations are prescribed for treatments where each individual drug address different symptoms of a particular medical situation. Although, a large number of therapeutic combinations could be provided, often they can not be compounded in the same dosage form because each drug needs to be administered on a different schedule. The different schedule is needed because different biological half lives and therapeutic indices, and therefore each drug should be administered in separate dosage forms on a prescribed schedule that is specific for each drug. Thus, a drug that needs to be administered four times a day, should not be combined with a drug that should be administered once a day. These drugs are kinetically incompatible in a pharmaceutical dosage form. Another reason why certain drugs cannot be combined is they may be chemically incompatible or unstable in the presence of each other. This kinetic or chemical incompatibility can be eliminated by the novel dosage form provided by this invention. For example, by using the dosage form provided by this invention, a regimen consisting of four times a day administration of drug can be transformed into a once a day administration such that the drug previously administered four times daily can be combined with a drug administered once daily. In other words, both drugs can be coadministered to the body at delivery rates that are matched to achieve each of their separate therapeutic plasma combinations. Thus, in the light of the above presentation, it will be appreciated by those versed in the dispensing art, that if a delivery device is made available for housing two or more different drugs at controlled and continuous rates in therapeutically effective amounts for obtaining the benefits of each drug, such a delivery device would have a definite use and be a valuable contribution to the dispensing art.
USPTO Backgrounds
USPTO Backgrounds