Formulation and process development of (recombinant human) deoxyribonuclease I as a powder for inhalation.

A formulation and process development study was performed to formulate recombinant human deoxyribonuclease I as a powder for inhalation. First, excipient compatibility (with bovine DNase as a model substance) was examined with a stability study at stressed conditions (60 and 85 degrees C) while monitoring for occurrence of the Maillard reaction. Next, powders for inhalation were prepared by spray drying and spray freeze drying. We found that spray drying with inulin as stabilizer resulted in the best powder for inhalation. Finally, an ex-vivo test with the spray dried rhDNase I/inulin powder significantly decreased elastic and viscous moduli of sputum from five cystic fibrosis patients.

Efficacy of a new pulmonary cyclosporine a powder formulation for prevention of transplant rejection in rats.

BACKGROUND: The aim of this pilot study was to determine the pharmacokinetics of cyclosporine A powder for inhalation (iCsA) and its rejection prevention efficacy in an experimental lung transplantation model in rats. METHODS: Single-dose pharmacokinetics (10 mg/kg) of pulmonary and orally administered cyclosporine A was determined in whole blood and in lung and kidney tissue. The efficacy of iCsA (2.5 and 5 mg/kg) in inhibiting rejection was determined in an orthotopic left-lung transplantation rat model and compared with orally administered CsA (5 and 10 mg/kg). The ventilation score of lung allografts was assessed with roentgenograms. At Day 10 post-operatively, the rats were terminated and lungs were prepared for histologic analysis. RESULTS: In the pharmacokinetics study, AUC(0-48) values in blood for iCsA and oral CsA were similar (47,790 +/- 1,739 and 46,987 +/- 2,439 ng h ml(-1), respectively). In contrast, iCsA levels in lung tissue were much higher than oral CsA levels (AUC: 9,152,977 +/- 698,920 vs 84,149 +/- 8,134 ng h g(-1), respectively), showing the effectiveness of the pulmonary administration. In the rejection study, non-treated animals showed complete rejection after 8 days according to roentgenography. Treatment with 5 mg/kg iCsA reduced rejection on Day 10, whereas the 2.5-mg/kg dose did not inhibit rejection. Oral CsA at 10 mg/kg reduced rejection, whereas the 5-mg/kg dose showed hardly any effect on rejection. CONCLUSIONS: We found that iCsA is an effective immunosuppressive formulation, and may become a valuable asset for clinical use in combination with systemic immunosuppression.

Mature enzymatic collagen cross-links, hydroxylysylpyridinoline and lysylpyridinoline, in the aging human vitreous.

PURPOSE: The vitreous body of the human eye undergoes progressive morphologic changes with aging. Since the enzymatic collagen cross-links hydroxylysylpyridinoline (HP) and lysylpyridinoline (LP) are known to be important for the integrity of the collagen matrix, the presence in the vitreous on aging was studied. METHODS: Vitreous bodies (VBs; n = 143) from 119 donors (age 4-80 years; mean +/- SD, 54.3 +/- 17.0 years) were carefully dissected. After weighing and freeze-drying, all samples were analyzed by high performance liquid chromatography. Left and right eyes of 24 donors were compared and, for age-related phenomena, 119 single eyes were used. RESULTS: Within one donor, no significant differences were found between left and right eyes. On aging, VB wet weight (4.42 +/- 0.84 g) accumulates until 35 years and decreases thereafter. Collagen content (0.30 +/- 0.14 mg), HP per triple helix (TH; 0.55 +/- 0.18), and (HP plus LP)/TH (0.61 +/- 0.19) increase until 50 years followed by a decrease, whereas LP/TH (0.057 +/- 0.018) accumulates until 50 years and remains constant thereafter. The ratio between HP and LP (range, 0.42-31.0; median, 10.0) is constant over time. CONCLUSIONS: The accumulation of enzymatic collagen cross-links until 50 years is consistent with collagen maturation and possible collagen synthesis in the human vitreous body. The decline of collagen cross-links after 50 years is consistent with collagen breakdown.

Characterization of a cyclosporine solid dispersion for inhalation.

For lung transplant patients, a respirable, inulin-based solid dispersion containing cyclosporine A (CsA) has been developed. The solid dispersions were prepared by spray freeze-drying. The solid dispersion was characterized by water vapor uptake, specific surface area analysis, and particle size analysis. Furthermore, the mode of inclusion of CsA in the dispersion was investigated with Fourier transform infrared spectroscopy. Finally, the dissolution behavior was determined and the aerosol that was formed by the powder was characterized. The powder had large specific surface areas (~ 160 m(2)). The water vapor uptake was dependant linearly on the drug load. The type of solid dispersion was a combination of a solid solution and solid suspension. At a 10% drug load, 55% of the CsA in the powder was in the form of a solid solution and 45% as solid suspension. At 50% drug load, the powder contained 90% of CsA as solid suspension. The powder showed excellent dispersion characteristics as shown by the high emitted fraction (95%), respirable fraction (75%), and fine-particle fraction (50%). The solid dispersions consisted of relatively large (x(50) approximately 7 mum), but low-density particles (rho approximately 0.2 g/cm(3)). The solid dispersions dissolved faster than the physical mixture, and inulin dissolved faster than CsA. The spray freeze-drying with inulin increased the specific surface area and wettability of CsA. In conclusion, the developed powder seems suitable for inhalation in the local treatment of lung transplant patients.

Spray freeze drying to produce a stable Delta(9)-tetrahydrocannabinol containing inulin-based solid dispersion powder suitable for inhalation.

The purpose of this study is to investigate whether spray freeze drying produces an inhalable solid dispersion powder in which Delta(9)-tetrahydrocannabinol (THC) is stabilised. Solutions of THC and inulin in a mixture of tertiary butanol (TBA) and water were spray freeze dried. Drug loads varied from 4 to 30 wt.%. Various powder characteristics of the materials were determined. Stability of THC was determined and compared with freeze dried material. The powders, dispersed with an inhaler based on air classifier technology, were subjected to laser diffraction analysis and cascade impactor analysis. Highly porous particles having large specific surface areas (about 90 m(2)/g) were produced. At high drug loads, THC was more effectively stabilised by spray freeze drying than by freeze drying. Higher cooling rates during spray freeze drying result in improved incorporation. Fine particle fractions of up to 50% were generated indicating suitability for inhalation. It was concluded that spray freeze drying from a water-TBA mixture is a suitable process to include lipophilic drugs (THC) in inulin glass matrices. High cooling rates during the freezing process result in effective stabilisation of THC. The powders can be dispersed into aerosols with a particle size appropriate for inhalation.

The role of particle engineering in relation to formulation and de-agglomeration principle in the development of a dry powder formulation for inhalation of cetrorelix.

We formulated cetrorelix acetate, as an adhesive mixture for use in dry powder inhalation. To achieve the highest possible deposition efficiency we investigated both the influence of different micronization techniques and different inhalers. The Novolizer with an air classifier as the powder de-agglomeration principle and the ISF inhaler were used for in vitro deposition experiments (cascade impaction). Micronization by milling as the classical approach and micronization by spray drying and spray freeze drying as advanced particle engineering techniques were investigated to determine whether advanced techniques are necessary to obtain high fine particle fractions (FPF) for this specific drug. It was found that the effects obtained with a certain micronization technique depended on the complex interaction of the physical characteristics of the drug substance with the type of formulation chosen, as well as with the de-agglomeration principle used. The combination of particle engineering by spray drying and the use of the air classifier technology resulted in a fine particle fraction of 66%, while spray freeze drying yielded extremely fragile particles resulting in a FPF of only 25%. The behaviour of the milled material showed similar trends as the spray dried material but FPF values were lower. It was concluded that when a drug is to be formulated as a powder for inhalation with high fine particle fractions, it is profitable to use advanced particle engineering techniques, however the applied technique should be tuned with the characteristics of the formulation type and process as well as with device development.

Pharmacoeconomic review of recombinant human DNase in the management of cystic fibrosis.

For the treatment of patients with cystic fibrosis, recombinant human deoxyribonuclease I is widely used. Deoxyribonuclease I has a positive effect on lung function and the number of hospitalizations. Deoxyribonuclease I is currently administered by nebulization, which is an inefficient administration method. For expensive drugs, such as deoxyribonuclease I, dry powder inhalation would be advantageous due to increased deposition efficiency, patient mobility and compliance. Furthermore, a significant cost reduction may be obtained. The current status of deoxyribonuclease I in the management of cystic fibrosis was investigated and special attention given to the developments in delivery systems, such as dry powder inhalation. It is estimated that if dry powder inhalation of deoxyribonuclease I could be used, a reduction in the cost-effectiveness ratio of approximately 40% can be obtained as compared with nebulization.