Excipient powder formulation

Nagel, K. M., Peck, G. E. Investigating the effects of excipients on the powder flow characteristics of theophyline anhydrous powder formulations. Drug Dev. Ind. Pharm., 29, 2003, 277-287. 

The finished form is a sterile, lyophilized powder formulated with tri-methamine, mannitol, and sucrose as excipients. 

Formulation of dry powders for inhalation must rely on a very short list of excipients to fulfill the customary roles of diluent, stabilizer, solubilizer, processing aid, and property modifier (e.g., flow enhancer). In the United States, only a few materials are approved for use in inhalation products, and of those (e.g., propellants, surfactants) many are of little help in dry powder formulation. 

Powdered bioadhesive formulations have attracted much interest for their ability to overcome mucociliary clearance in the nasal cavity. For example, powder formulations of freeze-dried mixtures of insulin and excipients such as crystalline cellulose, hydroxypropyl cellulose, or carbopol 934 have been shown to enhance the absorption of insulin in dogs from the nasal cavity compared to freeze-dried mixtures of insulin and lactose as an excipient [28,31], The improved delivery was attributed to both the improved dispersion of insulin and the high... 

The crystal structure of the cocrystal formed by celecoxib (4-[5-(4-methylphenyl)-3-(trifluoromethyl)-lH-pyrazol-l-yl]benzenesulfonamide) with nicotinamide has been solved from powder X-ray diffraction data [54], The dissolution and solubility of the cocrystal product were found to depend on the medium involved, and a number of the observed phenomena were shown to originate from differences in conversion of the cocrystal celecoxib polymorphic forms I and III. However, through the judicious use of choice excipients, a formulation was developed that took advantage of the crystalline conversion to be up to fourfold more bioavailable than the celecoxib Form-Ill marketed product. 

Many of these techniques involve particle formation from solution formulations that contain novel excipients. Spray drying is the most advanced of these technologies and has been used to produce the powder formulation in the Exubera inhaler [175], Various modifications of this basic technique, including co-spray drying with novel excipients, have been employed. 

Figure 5 Progress toward new excipients and new manufacturing technology for dry powder formulations.

Dry Powder Systems Dry powder formulations are susceptible to a number of potential interactions. Since there is currently only one approved excipient, the drugs have to be compatible with lactose 4 In addition, dry powders are prone to moisture sorption, which can give rise to chemical degradation by hydrolysis or physical instability due to capillary forces.44 As other excipients, such as lecithin, are explored as excipients in dry powder products, a hydrophobic effect... 

Cachet Capsule Herbal tea Powder Formulation Preparation Solid dosage form Tablet Content uniformity Excipients Adapting oral dosage forms... 

Thus the pharmacist must be careful when choosing the excipients. Pre-formulation studies to identify incompatibilities can be time-consuming but are required to prove that no instability of the active substance will occur during preparation and storage. In the case of the use of licensed products to prepare capsules or powders, it might be difficult to obtain information from the manufacturer. Thus, it is usually safe to dilute crushed tablet with the excipient that is used in the tablet formulation, based on the market authorisation holder who has ensured their compatibility. 

Some tablet formulations call for the inclusion of a small amount of semisolid, or even semiliquid, ingredient. It is highly desirable that any such component should be adsorbed onto, or absorbed into, one of the powders. In cases where none of the other excipients in the formulation is able to act as a carrier, an... 

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