DEVELOPMENT IN PHARMACEUTICAL DOSAGE FORM DESIGN DOSAGE FORM When a drug is prepared in a form suitable for administration, it is called a Dosage form or a drug product or, in a modern term, a Drug delivery system PRE-HISTORIC PERIODS • Chewing leaves and roots of medicinal plants • Inhaling soot from the burning of medicinal substances • Primitive extracts from plants and animals GENERATION BASED CLASSIFICATION First Generation DDS Second Generation DDS Third Generation DDS Fourth Generation DDS Fifth Generation DDS FIRST GENERATION DRUG DELIVERY SYSTEM Appeared toward the end of the nineteenth century and in the twentieth century Conventional and still very popular Having consistency and uniformity Tablets, capsules, elixirs, syrups, suspensions, emulsions, solutions and topical administration of ointments, lotions and creams, suppositories or injection of suspensions and solution SECOND GENERATION DRUG DELIVERY SYSTEM Modification of the conventional dosage forms Protect drugs against hostile conditions along the gastrointestinal tract, Prolong action Improve bioavailability Repeat action, prolonged action, timed release, delayed release, enteric coated solid dosage forms. THIRD GENERATION DRUG DELIVERY SYSTEM Controlled drug delivery-a new concept introduced in 1960’s “Refers to the precise control of the rate at which a drug dosage is released from a delivery system, ideally in a constant or near constant manner over a longer period of time” Objectives Reduced dosing frequency Improving patient compliance Increase duration of effect Maintain constant drug level in blood Reducing side effect by lowering Cmax Classified as Osmotic controlled DDS Swelling Controlled DDS Magnetically Controlled DDS Chemically controlled DDS Electrically controlled DDS Diffusion controlled DDS Fourth Generation Drug Delivery System Based on Delivering drug that could exercise control on the time of availability and localization of the drug in the body. Classified as Targeted or site specific drug delivery system such as GI targeting of peptide and protein Immunotherapy such as Monoclonal antibodies, Antisense Compounds, Recombinant vaccines and angiogenesis inhibitors. Plulsatile or modulated drug delivery system – also termed as chronotherapeutics i.e. delivering drug based on chronobiology or science of biological rhythm. Self regulated or Feedback Controlled Drug delivery system Biosensor pump combinations Closed loop based on self regulating system Closed loop based on microencapsulated secretory cells Fifth Generation Drug Delivery System Based on Treating the cause of disease rather than symptoms. Types are Gene Therapy-Redesign of cells by introducing the therapeutic genes into genetically disabled cells to deliver therapeutic agents made by gene.
