Inhaled Drug Delivery Design

TABLE 8.5 Predicted Cohesive Energy of Inhalation Formnlation Components (LMH,FP,BUD, SB)  

Forms (kcal/mol) Forms (kcal/mol) Forms (kcal/mol) Forms (kcal/mol) 

Thus the prediction showed that FP (-11.5 kcal/mol) has the highest cohesive strength when compared to BUD (-9.9 kcal/mol) or SB (-7.8 kcal/mol) and this ranking correlated well to the laser diffraction measurements where the airflow pressure required for complete dispersion (CPP) was 3.5, 2.0 and 1.0 Bar for FP, BUD and SB, respectively. This case study demonstrates that the technologies also have the potential to be used as predictive tools for assessing the cohesive-adhesive strength balance for inhaled drug formulations. 

TABLE 8.6 Analysis of the Structural Factors Related to Likely Slip Due to Mechanical Deformation° 

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Atkins, P.J. Barker, N.P. Mathisen, D. The design and development of inhalation drug delivery systems. In Pharmaceutical Inhalation Pressurised Metered-Dose Inhaler Technology, Hickey, A.J., Ed. Marcel Dekker, Inc. New York, 1992. 

The Design and Development of Inhalation Drug Delivery Systems... 

PREFORMULATION ASPECTS ON INHALATION DRUG DELIVERY SYSTEM DESIGN... 

INHALATION DRUG DELIVERY SYSTEM DESIGN—NEBULIZED DRUG DELIVERY... 

INHALATION DRUG DELIVERY SYSTEM DESIGN—METERED-DOSE INHALERS Introduction... 

Presently, relatively little is known about the potency of drugs of abuse after inhalation or smoking. In order to deter-mine the relationship between volatility and pharmacological potency by the inhalation route, the authors developed an animal model to approximate the conditions of human inhalation. The approach involved a volatilization-inhalation drug delivery system developed over the past 10 years in this laboratory. The design of this inhalation apparatus is illustrated in figure 2. 

Intimately related to these factors is the design of the device, formulation, and the interface with the patient. Much of the discussion below will focus on the implications of excipients on formulation challenges for inhaled aerosol products. This chapter summarizes excipients for pulmonary formulations from several perspectives (i) excipient selection based on principles of delivery, (ii) physicochemical requirements for excipients, and (iii) specific challenges for formulations faced with aerosol drug delivery systems, including (a) biological aspects, (b) microbiological aspects, (c) analytical issues, and (d) future prospects. 

Peart, J. Magyar, C. Byron, P.R. Aerosol electrostatics— metered dose inhalers (MDIs) reformulation and device design issues. In Respiratory Drug Delivery VT, Dalby, R.N., Byron, P.R., Farr, S.J., Eds. Interpharm Press Buffalo Grove, IL, 1998 227-233. 

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