In inhaled formulations

In light of the information presented, it appears that liposomes have much to offer as an improved delivery system for inhaled bronchodilators as they can provide sustained release, solubilization, stability, and safety in an inhalable formulation. 

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. 

Excipients are sub-divided into various functional classifications, depending on the role that they are intended to play in the resultant formulation, for example, fillers, disintegrants, binders, lubricants and glidants. An added complexity is the fact that certain excipients can have different functional roles in different formulation types. Thus, lactose is widely used as a filler or diluent in solid oral dosage forms, for example, tablets and capsules [2] and as a carrier for inhalation products [3]. 

Ribavirin is contraindicated in patients with sickle cell anemia and other hemoglobinopathies because of its propensity to cause anemia. Similarly, persons with coronary disease should not use ribavirin, because anemia may cause deterioration of cardiac function. Oral ribavirin should not be given to individuals with severe renal impairment no dosage adjustment is necessary for the inhaled formulation. However, patients with hepatic impairment may require dosage adjustment. 

Johnson KA. Interfacial phenomena and phase behavior in metered-dose inhaler formulations. In Hickey AJ, ed. Inhalation Aerosols. New York Marcel Dekker, 1996 385-415. 

Buckton G. Characterization of small changes in the physical properties of powders of significance for dry powder inhaler formulations. Adv Drug Delivery Rev 1997 26 17-27. 

Protein-based drugs have been formulated mainly as stable liquids or in cases where liquid stability is limiting as lyophilized dosage forms to be reconstituted with a suitable diluent prior to injection. This is because their delivery has been limited primarily to the parenteral routes of intravenous (IV), subcutaneous (SC), or intramuscular (IM) administration. There are a few drugs that have been developed for pulmonary delivery, such as rhDNase (Pulmozyme ) and an inhalable formulation of insulin (e.g., Exubra ). However, even such drugs have been formulated as either liquid or lyophilized or spray-dried powders. This chapter will focus only on excipients that are applicable to liquid and lyophilized protein formulations. 

Fewer than 12 different excipients in MDI products have been formulated into metered aerosols. The availability of established FDA-approved excipients limits the formulator to a select few such ingredients. Table 1 lists excipients and the approximate amounts of some of these excipients that are currently used in MDIs. Metered-dose inhalers formulated with CFCs contain propellant 12, propellant 12/11, propellant 12/114, or propellant 12/114/11. These propellant... 

Ultimately chemical images have the ability to show API adhering to other formulation excipients which is not possible by other sizing methods. Statistically, laser diffraction methods have less errors in the measurement as they measure millions of particle compared to the hundreds by Raman chemical imaging, but their lack of specificity means the whole sample is measured and not just the API. Ultimately the Raman method is still under development but provides the formulators of inhaled products an additional tool in understanding formulation properties and product. 

Several other therapeutic effects of sodium channel blockers have been suggested. Most of these stem from clinical activities of approved anticonvulsants and antiarrhythmics with sodium channel blocking activity. Beneficial effects of sodium channel blockers for the treatment of bipolar disease are suggested by clinical data with lamotrigine [63-67], phenytoin [68], topiramate [69], and carbamazepine [70,71]. In addition, clinical studies with lidocaine suggest efficacy in the treatment of tinnitus [72] and, as an inhaled formulation, in the suppression of cough [73,74]. 

The eucalyptus essential oils find widespread applications in pharmaceutical formulations like mouthwashes, inhalers, hygiene and cleansing products such as soaps and detergents, for room sprays and insect repellents, as a flavouring in foods, in perfumery and as a starting material for industrial compounds that are extracted, mainly by distillation. For aromatherapy, the oils can be used for skin care, the respiratory system, the immune system, the nervous system, the urino-genital system and the musculo-skel-etal system. 

Salbutamol is available as tablets, inhalers, nebuliser solution and intravenous injection. In the management of asthma at step 1 and 2 the inhaled formulation is the best option since it targets the drug and minimises side-effects. Oral tablets of salbutamol are rarely used and there is limited evidence of their effectiveness. 

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