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1.
Pharm Dev Technol ; 29(5): 395-414, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38618690

ABSTRACT

The MCS initiative was first introduced in 2013. Since then, two MCS papers have been published: the first proposing a structured approach to consider the impact of drug substance physical properties on manufacturability and the second outlining real world examples of MCS principles. By 2023, both publications had been extensively cited by over 240 publications. This article firstly reviews this citing work and considers how the MCS concepts have been received and are being applied. Secondly, we will extend the MCS framework to continuous manufacture. The review structure follows the flow of drug product development focussing first on optimisation of API properties. The exploitation of links between API particle properties and manufacturability using large datasets seems particularly promising. Subsequently, applications of the MCS for formulation design include a detailed look at the impact of percolation threshold, the role of excipients and how other classification systems can be of assistance. The final review section focusses on manufacturing process development, covering the impact of strain rate sensitivity and modelling applications. The second part of the paper focuses on continuous processing proposing a parallel MCS framework alongside the existing batch manufacturing guidance. Specifically, we propose that continuous direct compression can accommodate a wider range of API properties compared to its batch equivalent.


Subject(s)
Excipients , Technology, Pharmaceutical , Excipients/chemistry , Technology, Pharmaceutical/methods , Pharmaceutical Preparations/chemistry , Chemistry, Pharmaceutical/methods , Drug Compounding/methods , Drug Industry/methods
2.
Expert Opin Drug Deliv ; : 1-13, 2024 Mar 30.
Article in English | MEDLINE | ID: mdl-38555481

ABSTRACT

BACKGROUND: Pain is characterized as a major symptom induced by tissue damage occurring from surgical procedures, whose potency is being experienced subjectively, while current pain relief strategies are not always efficient in providing individualized treatment. 3D printed implantable devices hold the potential to offer a precise and customized medicinal approach, targeting both tissue engineering and drug delivery. RESEARCH DESIGN AND METHODS: Polycaprolactone (PCL) and PCL - chitosan (CS) composite scaffolds loaded with procaine (PRC) were fabricated by bioprinting. Geometrical features including dimensions, pattern, and infill of the scaffolds were mathematically optimized and digitally determined, aiming at developing structurally uniform 3D printed models. Printability studies based on thermal imaging of the bioprinting system were performed, and physicochemical, surface, and mechanical attributes of the extruded scaffolds were evaluated. The release rate of PRC was examined at different time intervals up to 1 week. RESULTS: Physicochemical stability and mechanical integrity of the scaffolds were studied, while in vitro drug release studies revealed that CS contributes to the sustained release dynamic of PRC. CONCLUSIONS: The printing extrusion process was capable of developing implantable devices for a local and sustained delivery of PRC as a 7-day adjuvant regimen in post-operative pain management.

3.
Int J Pharm ; 653: 123902, 2024 Mar 25.
Article in English | MEDLINE | ID: mdl-38360287

ABSTRACT

Three-dimensional printing (3DP) is an emerging technology, offering the possibility for the development of dose-customized, effective, and safe solid oral dosage forms (SODFs). Although 3DP has great potential, it does come with certain limitations, and the traditional drug manufacturing platforms remain the industry standard. The consensus appears to be that 3DP technology is expected to benefit personalized medicine the most, but that it is unlikely to replace conventional manufacturing for mass production. The 3DP method, on the other hand, could prove well-suited for producing small batches as an adaptive manufacturing technique for enabling adaptive clinical trial design for early clinical studies. The purpose of this review is to discuss recent advancements in 3DP technologies for SODFs and to focus on the applications for SODFs in the early clinical development stages, including a discussion of current regulatory challenges and quality controls.


Subject(s)
Precision Medicine , Printing, Three-Dimensional , Precision Medicine/methods , Industry , Quality Control , Pharmaceutical Preparations , Technology, Pharmaceutical/methods , Dosage Forms
4.
Pharmaceutics ; 15(3)2023 Mar 06.
Article in English | MEDLINE | ID: mdl-36986716

ABSTRACT

The aim of this study was to develop antisense oligonucleotide tablet formulations using high-speed electrospinning. Hydroxypropyl-beta-cyclodextrin (HPßCD) was used as a stabilizer and as an electrospinning matrix. In order to optimize the morphology of the fibers, electrospinning of various formulations was carried out using water, methanol/water (1:1), and methanol as solvents. The results showed that using methanol could be advantageous due to the lower viscosity threshold for fiber formation enabling higher potential drug loadings by using less excipient. To increase the productivity of electrospinning, high-speed electrospinning technology was utilized and HPßCD fibers containing 9.1% antisense oligonucleotide were prepared at a rate of ~330 g/h. Furthermore, to increase the drug content of the fibers, a formulation with a 50% drug loading was developed. The fibers had excellent grindability but poor flowability. The ground fibrous powder was mixed with excipients to improve its flowability, which enabled the automatic tableting of the mixture by direct compression. The fibrous HPßCD-antisense oligonucleotide formulations showed no sign of physical or chemical degradation over the 1-year stability study, which also shows the suitability of the HPßCD matrix for the formulation of biopharmaceuticals. The obtained results demonstrate possible solutions for the challenges of electrospinning such as scale-up and downstream processing of the fibers.

5.
Int J Pharm ; 613: 121413, 2022 Feb 05.
Article in English | MEDLINE | ID: mdl-34954004

ABSTRACT

The present paper reports the powder filling of milled electrospun materials in vials, which contained voriconazole and sulfobutylether-ß-cyclodextrin. High-speed electrospinning was used for the production of the fibrous sample, which was divided into 6 parts. Each portion was milled using different milling methods and sizes of sieves to investigate whether the milling influences the powder and filling properties. Bulk and tapped density tests, laser diffraction and angle of repose measurements were applied to characterize the milled powders, while a vibratory feeder was used for the feeding experiments. The correlation between the material property descriptors and the feeding responses was investigated by multivariate data analysis. Based on the results, three samples were chosen for the vial filling, which was accomplished with 3400 mg electrospun material containing 200 mg voriconazole, representative of the commercial product. The feed rate was set to fit the 240 g/h production rate of the electrospinning and the relative standard deviation of three repeated vial filling was determined to see the accuracy of the process. This research shows that by applying a suitable milling method it is possible to process electrospun fibers to a powder, which can be filled into vials and used as reconstitution dosage forms.


Subject(s)
Emollients , Technology, Pharmaceutical , Powders , Proof of Concept Study , Voriconazole
6.
Eur J Pharm Sci ; 164: 105907, 2021 Sep 01.
Article in English | MEDLINE | ID: mdl-34118411

ABSTRACT

Electrospinning is a technology for manufacture of nano- and micro-sized fibers, which can enhance the dissolution properties of poorly water-soluble drugs. Tableting of electrospun fibers have been demonstrated in several studies, however, continuous manufacturing of tablets have not been realized yet. This research presents the first integrated continuous processing of milled drug-loaded electrospun materials to tablet form supplemented by process analytical tools for monitoring the active pharmaceutical ingredient (API) content. Electrospun fibers of an amorphous solid dispersion (ASD) of itraconazole and poly(vinylpyrrolidone-co-vinyl acetate) were produced using high speed electrospinning and afterwards milled. The milled fibers with an average fiber diameter of 1.6 ± 0.9 µm were continuously fed with a vibratory feeder into a twin-screw blender, which was integrated with a tableting machine to prepare tablets with ~ 10 kN compression force. The blend of fibers and excipients leaving the continuous blender was characterized with a bulk density of 0.43 g/cm3 and proved to be suitable for direct tablet compression. The ASD content, and thus the API content was determined in-line before tableting and at-line after tableting using near-infrared and Raman spectroscopy. The prepared tablets fulfilled the USP <905> content uniformity requirement based on the API content of ten randomly selected tablets. This work highlights that combining the advantages of electrospinning (e.g. less solvent, fast and gentle drying, low energy consumption, and amorphous products with high specific surface area) and the continuous technologies opens a new and effective way in the field of manufacturing of the poorly water-soluble APIs.


Subject(s)
Excipients , Spectrum Analysis, Raman , Desiccation , Drug Compounding , Itraconazole , Tablets , Technology, Pharmaceutical
7.
Int J Pharm ; 591: 120042, 2020 Dec 15.
Article in English | MEDLINE | ID: mdl-33157211

ABSTRACT

Solid formulations of monoclonal antibodies present several advantages, such as improved stability and increased shelf-life as well as simpler storage and transportation. In this study, we present a gentle drying technology for monoclonal antibodies, applying the water soluble 2-hydroxypropyl-ß-cyclodextrin (HP-ß-CD) as matrix, to prepare a solid reconstitution dosage form. High-speed electrospinning of an aqueous infliximab-containing HP-ß-CD solution was carried out at 25 °C resulting in fibers with an average diameter of 2.5 µm. The mAb-loaded electrospun fibers were successful to preserve the stability of infliximab in solid form. The results of size exclusion chromatography and gel electrophoresis indicated no significant increase in aggregate formation during the electrospinning process compared to the initial matrix solution. The binding activity of infliximab was preserved during electrospinning compared to the reference liquid formulation. Due to the enhanced surface area, excellent reconstitution capability, i.e. clear solution within 2 min without any vigorous mixing, could be achieved in a small-scale reconstitution test. The results of this work demonstrate that high-speed electrospinning is a very promising technique to manufacture the solid formulation of monoclonal antibodies for applications such as fast reconstitutable powders.


Subject(s)
Antibodies, Monoclonal , Desiccation , 2-Hydroxypropyl-beta-cyclodextrin , Powders , Solubility , Water
8.
AAPS PharmSciTech ; 21(6): 214, 2020 Jul 31.
Article in English | MEDLINE | ID: mdl-32737608

ABSTRACT

A model anaerobic bacterium strain from the gut microbiome (Clostridium butyricum) producing anti-inflammatory molecules was incorporated into polymer-free fibers of a water-soluble cyclodextrin matrix (HP-ß-CD) using a promising scaled-up nanotechnology, high-speed electrospinning. A long-term stability study was also carried out on the bacteria in the fibers. Effect of storage conditions (temperature, presence of oxygen) and growth conditions on the bacterial viability in the fibers was investigated. The viability of the sporulated anaerobic bacteria in the fibers was maintained during 12 months of room temperature storage in the presence of oxygen. Direct compression was used to prepare tablets from the produced bacteria-containing fibers after milling (using an oscillating mill) and mixing with tableting excipients, making easy oral administration of the bacteria possible. No significant decrease was observed in bacterial viability following the processing of the fibers (milling and tableting).


Subject(s)
Bacteria, Anaerobic/isolation & purification , Clostridium butyricum/isolation & purification , Drug Compounding , Gastrointestinal Microbiome , Anaerobiosis , Bacteria, Anaerobic/genetics , Clostridium butyricum/genetics , Excipients , Humans , Phylogeny , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Tablets , Temperature
9.
Eur J Pharm Sci ; 141: 105089, 2020 Jan 01.
Article in English | MEDLINE | ID: mdl-31626967

ABSTRACT

The goals of this work were to evaluate if high-speed electrospinning can be used as a gentle and continuous drying technology to produce protein-containing cyclodextrin-based fibers from an aqueous solution and to convert the produced protein-cyclodextrin fibers into a directly compressible powder. A 400 mL/h feeding rate was used during the electrospinning experiments, corresponding to a ~270 g/h production rate of the dried material. The produced fibers were collected in a cyclone. The fibers were found grindable without secondary drying, and the ground powder was mixed with tableting excipients and was successfully tableted by direct compression. The model protein-type drug (ß-galactosidase) remained stable during each of the processing steps (electrospinning, grinding, tableting) and after 6 months of storage at room temperature in the tablets. The obtained results demonstrate that high speed electrospinning can be a gentle alternative to traditional drying methods used for protein-type drugs, and that tablet formulation is achievable from the electrospun material prepared this way.


Subject(s)
2-Hydroxypropyl-beta-cyclodextrin/chemistry , Technology, Pharmaceutical/methods , beta-Galactosidase/chemistry , Desiccation , Enzyme Stability , Powders , Tablets
10.
Article in English | MEDLINE | ID: mdl-31863572

ABSTRACT

Recently, electrospinning (ES) of fibers has been shown to be an attractive strategy for drug delivery. One of the main features of ES is that a wide variety of drugs can be loaded into the fibers to improve their bioavailability, to enhance dissolution, or to achieve controlled release. Besides, ES is a continuous technology with low energy consumption, which can make it a very economic production alternative to the widely used freeze drying and spray drying. However, the low production rate of laboratory-scaled ES has limited the industrial application of the technology so far. This article covers the various ES technologies developed for scaled-up fiber production with an emphasis on pharmaceutically relevant examples. The methods used for increasing the productivity are complied, which is followed by a review of specific examples from literature where these technologies are utilized to produce oral drug delivery systems. The different technologies are compared in terms of their basic principles, advantages, and limitations. Finally, the different downstream processing options to prepare tablets or capsules containing the electrospun drug are covered as well. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.


Subject(s)
Drug Industry , Nanotechnology , Drug Delivery Systems , Humans , Nanofibers/chemistry
11.
Pharmaceutics ; 11(7)2019 Jul 11.
Article in English | MEDLINE | ID: mdl-31336743

ABSTRACT

The aims of this work were to develop a processable, electrospun formulation of a model biopharmaceutical drug, ß-galactosidase, and to demonstrate that higher production rates of biopharmaceutical-containing fibers can be achieved by using high-speed electrospinning compared to traditional electrospinning techniques. An aqueous solution of 7.6 w/w% polyvinyl alcohol, 0.6 w/w% polyethylene oxide, 9.9 w/w% mannitol, and 5.4 w/w% ß-galactosidase was successfully electrospun with a 30 mL/h feeding rate, which is about 30 times higher than the feeding rate usually attained with single-needle electrospinning. According to X-ray diffraction measurements, polyvinyl alcohol, polyethylene oxide, and ß-galactosidase were in an amorphous state in the fibers, whereas mannitol was crystalline (δ-polymorph). The presence of crystalline mannitol and the low water content enabled appropriate grinding of the fibrous sample without secondary drying. The ground powder was mixed with excipients commonly used during the preparation of pharmaceutical tablets and was successfully compressed into tablets. ß-galactosidase remained stable during each of the processing steps (electrospinning, grinding, and tableting) and after one year of storage at room temperature in the tablets. The obtained results demonstrate that high-speed electrospinning is a viable alternative to traditional biopharmaceutical drying methods, especially for heat sensitive molecules, and tablet formulation is achievable from the electrospun material prepared this way.

12.
J Control Release ; 298: 120-127, 2019 03 28.
Article in English | MEDLINE | ID: mdl-30779951

ABSTRACT

The aims of this study were to evaluate electrospinning as a continuous alternative to freeze drying in the production of a reconstitution injection dosage form, and to prove that aqueous electrospinning can be realized with a high production rate at room temperature. High-speed electrospinning with a novel continuous cyclone collection was used to manufacture a formulation of the poorly water-soluble antifungal voriconazole (VOR) with sulfobutylether-ß-cyclodextrin (SBE-ß-CD). The freeze-dried, marketed product of this drug substance, Vfend® also contains SBE-ß-CD as excipient. SBE-ß-CD acted as a 'quasi-polymer', and it could be electrospun despite its low molecular mass (2163 Da). According to X-ray diffraction and differential scanning calorimetry, no traces of crystalline VOR were detectable in the fibers. Furthermore, Raman mapping and energy dispersive spectroscopy measurements showed a uniform distribution of amorphous VOR in the fibers. Reconstitution tests carried out with ground fibrous powder showed complete dissolution resulting in a clear solution after 30 s (similarly to Vfend®). The high productivity rate (~240 g/h) achieved using high-speed electrospinning makes this scaled-up, continuous and flexible manufacturing process capable of fulfilling the technological and capacity requirements of the pharmaceutical industry. This work shows that aqueous high-speed electrospinning, being a continuous and high-throughput process, is an economically viable production alternative to freeze drying.


Subject(s)
Antifungal Agents/administration & dosage , Technology, Pharmaceutical/methods , Voriconazole/administration & dosage , beta-Cyclodextrins/chemistry , Antifungal Agents/chemistry , Chemistry, Pharmaceutical/methods , Crystallization , Excipients/chemistry , Freeze Drying , Powders , Solubility , Temperature , Voriconazole/chemistry
13.
J Control Release ; 296: 162-178, 2019 02 28.
Article in English | MEDLINE | ID: mdl-30677436

ABSTRACT

In chronic intestinal diseases like inflammatory bowel disease, parenteral administration of biopharmaceuticals is associated with numerous disadvantages including immune reactions, infections, low patient compliance, and toxicity caused by high systemic bioavailability. One alternative that can potentially overcome these limitations is oral administration of biopharmaceuticals, where the local delivery will reduce the systemic exposure and furthermore the manufacturing costs will be lower. However, the development of oral dosage forms that deliver the biologically active form to the intestines is one of the greatest challenges for pharmaceutical technologists due to the sensitive nature of biopharmaceuticals. The present article discusses the various drug delivery technologies used to produce orally administered solid dosage forms of biopharmaceuticals with an emphasis on colon-targeted delivery. Solid oral dosage compositions containing different types of colon-targeting biopharmaceuticals are compiled followed by a review of currently applied and emerging drying technologies for biopharmaceuticals. The different drying technologies are compared in terms of their advantages, limitations, costs and their effect on product stability.


Subject(s)
Biological Products/chemistry , Desiccation , Drug Delivery Systems , Technology, Pharmaceutical/methods , Administration, Oral , Animals , Biological Products/administration & dosage , Colon , Humans
14.
J Med Screen ; 22(2): 83-92, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25576339

ABSTRACT

OBJECTIVES: Mammography screening programme sensitivity is evaluated by comparing the interval cancer rate (ICR) with the expected breast cancer incidence without screening, ie. the proportional interval cancer rate (PICR). The PICR is usually found by extrapolating pre-screening incidence rates, whereas ICR is calculated from data available in the screening programmes. As there is no consensus regarding estimation of background incidence, we seek to validate the ICR measure against the PICR. METHODS: Screening data from the three mammography screening programmes of Stockholm, Copenhagen, and Funen in the period 1989-2011 provided data to calculate the ICR. The most commonly described methods of extrapolating pre-screening incidence rates to calculate the PICR were illustrated and PICRs were calculated by year and programme using these different methods and compared with the ICRs. RESULTS: PICRs varied greatly, reaching a difference of 32-34% in Stockholm, 79% in Copenhagen, and 100-106% in Funen between the highest and the lowest value, depending on which method was applied. PICRs exhibited large variations yearly and from programme to programme. ICRs did not vary to the same extent, ranging on average from 0.100 to 0.136 in the first 12-months and between 0.201 and 0.225 in the last 12-months of the two-year period after a negative screen across the three programmes. CONCLUSION: The value of the PICR is hugely influenced by which method is applied, whereas the ICR is calculated purely on data available within programmes. We find that the PICR, the establishing indicator for sensitivity, could preferably be replaced by the ICR.


Subject(s)
Early Detection of Cancer , Mammography , Aged , Breast Neoplasms/diagnosis , Early Detection of Cancer/methods , Female , Humans , Incidence , Mammography/methods , Mass Screening/methods , Middle Aged
15.
Eur J Epidemiol ; 30(2): 143-9, 2015 Feb.
Article in English | MEDLINE | ID: mdl-25421784

ABSTRACT

Inspired by the model by Walter and Day for risk of cervical cancer following negative screens, one might hypothesize that women in a mammography screening programme with a certain number of negative screens had a lower remaining breast cancer risk than that of women in general. We studied whether number of negative screens was a predictor for a low remaining breast cancer risk in women participating in the mammography screening programmes in Stockholm, Copenhagen and Funen. Data were collected from the mammography screening programmes in Stockholm, Sweden (1989-2012), Copenhagen, Denmark (1991-2009) and Funen, Denmark (1993-2009), and linked to the respective cancer registries. We calculated cumulative hazard rates for breast cancer in women in cohorts defined by age at entry and number of negative screens for the maximum follow-up period in each screening centre. For all centres and cohorts, the cumulative hazard were parallel for all number of negative screens, from after the time, when the women were scheduled to be invited for the next screen. This means that the remaining breast cancer risk is similar no matter how many negative screens a woman have had. Number of negative screens was not a predictor of a low remaining breast cancer risk in women participating in the mammography screening programmes in Stockholm, Sweden, Copenhagen and Funen, Denmark. The history of previous negative screens is therefore not suitable for personalisation of mammography screening.


Subject(s)
Breast Neoplasms/diagnostic imaging , Forecasting , Mammography/statistics & numerical data , Mass Screening , Aged , Denmark , Early Detection of Cancer , Female , Follow-Up Studies , Humans , Middle Aged , Predictive Value of Tests , Sweden
16.
BMC Cancer ; 14: 782, 2014 Oct 24.
Article in English | MEDLINE | ID: mdl-25344115

ABSTRACT

BACKGROUND: The sensitivity of a mammography program is normally evaluated by comparing the interval cancer rate to the expected breast cancer incidence without screening, i.e. the proportional interval cancer rate (PICR). The expected breast cancer incidence in absence of screening is, however, difficult to estimate when a program has been running for some time. As an alternative to the PICR we propose the interval cancer ratio ICR=intervalcancersintervalcancers+screendetectedcancers. We validated this simple measure by comparing it with the traditionally used PICR. METHOD: We undertook a systematic review and included studies: 1) covering a service screening program, 2) women aged 50-69 years, 3) observed data, 4) interval cancers, women screened, or interval cancer rate, screen detected cases, or screen detection rate, and 5) estimated breast cancer incidence rate of background population. This resulted in 5 papers describing 12 mammography screening programs. RESULTS: Covering initial screens only, the ICR varied from 0.10 to 0.28 while the PICR varied from 0.22 to 0.51. For subsequent screens only, the ICR varied from 0.22 to 0.37 and the PICR from 0.28 to 0.51. There was a strong positive correlation between the ICR and the PICR for initial screens (r = 0.81), but less so for subsequent screens (r = 0.65). CONCLUSION: This alternate measure seems to capture the burden of interval cancers just as well as the traditional PICR, without need for the increasingly difficult estimation of background incidence, making it a more accessible tool when evaluating mammography screening program performance.


Subject(s)
Breast Neoplasms/diagnosis , Early Detection of Cancer/methods , Mass Screening/methods , Aged , Breast Neoplasms/epidemiology , Female , Humans , Incidence , Mammography/methods , Middle Aged , Program Evaluation
17.
Pharm Res ; 31(11): 2940-51, 2014 Nov.
Article in English | MEDLINE | ID: mdl-24867422

ABSTRACT

PURPOSE: The purpose of this study was to modulate the release profiles of the model protein drug from spray dried poly(DL-lactic-co-glycolic acid) (PLGA) microparticles by incorporating hyaluronic acid (HA) in the formulation. METHODS: Bovine serum albumin (BSA)-loaded PLGA microparticles with or without HA were prepared using a spray dryer equipped with a 3-fluid nozzle. The effects of HA on the surface tension and the rheological behavior of the inner feed solution were investigated. The physicochemical properties of the resulting microparticles were characterized using scanning electron microscopy (SEM), laser diffraction (LD), confocal laser scanning microscopy (CLSM) and X-ray photoelectron spectroscopy (XPS). Circular dischoism (CD) was used to characterize conformational integrity of BSA released from the microparticles. RESULTS: Spherical microparticles with D50 of 5-10 µm were obtained. Addition of HA in inner feed solutions increased the feed viscosity, but with no influence on the surface tension. All inner feed solutions showed non-Newtonian shear thinning behavior and the rheological properties were not time dependent. The CLSM and XPS analyses suggested a core-shell like structure of the microparticles when HA was incorporated. The release profiles of BSA were extended and the initial burst releases were suppressed with an increase in HA in the microparticle formulations. In addition, HA seemed to protect BSA from degradation upon the spray-drying process. CONCLUSIONS: The present work demonstrates the potential of HA to modulate protein release profile from PLGA microparticle formulations produced via spray drying using 3-fluid nozzle.


Subject(s)
Drug Compounding/methods , Hyaluronic Acid/chemistry , Lactic Acid/chemistry , Polyglycolic Acid/chemistry , Proteins/chemistry , Chemistry, Pharmaceutical/methods , Drug Carriers/chemistry , Microspheres , Particle Size , Polylactic Acid-Polyglycolic Acid Copolymer , Rheology , Serum Albumin, Bovine/chemistry , Solutions/chemistry , Surface Tension
18.
Pharm Res ; 31(8): 1967-77, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24549821

ABSTRACT

PURPOSE: The aim of this study was to investigate the potential of using a spray-dryer equipped with a 3-fluid nozzle to microencapsulate protein drugs into polymeric microparticles. METHODS: Lysozyme and PLGA were used as a model protein and a model polymer, respectively. The effects of process and formulation variables, such as i) the type of organic solvent, ii) the feeding rate ratio of the outer PLGA-containing feed solution to inner lysozyme-containing feed solution, and iii) the mass ratio of PLGA to protein, on the properties (morphology, internal structure, protein surface enrichment and release profiles) of the spray dried microparticles were investigated to understand protein microencapsulation and particle formation mechanisms. RESULTS: The spherical, condensed microparticles were obtained with D50 of 1.07-1.60 µm and Span in the range of 0.82-1.23. The lysozyme surface content decreased upon different organic solvents used as follows: acetonitrile > acetone > dichloromethane. Additionally, the lysozyme surface enrichment decreased slightly when increasing the feeding rate ratio of the outer feed solution to the inner feed solution from 4:1 to 10:1. Furthermore, it was observed that there was a correlation between the degree of burst release and the lysozyme surface enrichment, whereas the lysozyme loading content had no substantial impact on the release kinetics. CONCLUSIONS: The present work demonstrates the potential of spray dryer equipped with a 3-fluid nozzle in microencapsulation of proteins into PLGA matrices with different characteristics by varying process and formulation parameters.


Subject(s)
Drug Carriers/chemical synthesis , Drug Compounding/methods , Lactic Acid/chemical synthesis , Microspheres , Muramidase/chemical synthesis , Polyglycolic Acid/chemical synthesis , Animals , Chemistry, Pharmaceutical/methods , Chickens , Polylactic Acid-Polyglycolic Acid Copolymer
19.
Acta Oncol ; 47(4): 550-5, 2008.
Article in English | MEDLINE | ID: mdl-18465321

ABSTRACT

INTRODUCTION: There is an ongoing debate concerning possible disadvantages of mammography screening, one being the consequence of receiving a false positive test-result. It is argued that receiving a false positive answer may have short- and/or long-term adverse psychological effects on women, but results from different studies are conflicting. We tested if there was a difference in continued participation behaviour between the group of women who have been subject to a false positive result and those who have not. MATERIAL AND METHODS: The study used the registers from the first six invitation rounds of the mammography screening programme in Copenhagen (1991-2003). We estimated the relative risk of not participating in the subsequent screening round for women with a false positive test using women with a negative test as baseline. As outcome measure odds ratios (OR) with 95% confidence intervals (CI) were used. RESULTS: There was no significant difference in participation in the subsequent round between women with a false positive test and women with a negative test. The proportion of screens resulting in false positive answers, both after assessment and after surgery, decreased from 5.54% in Round 1 to 1.79% in Round 5. Participation in the subsequent screening round was well above 80% in all five screening rounds. DISCUSSION: Our results showed that women experiencing a false positive test at mammography screening participated in the subsequent screening round to the same extent as did women experiencing a negative screening test, regardless of whether the false positive statement was given following assessment or following surgery. The benign to malignant biopsy ratio, comparing the type B false positives to the true positives, was by the fifth round well below the desirable level of

Subject(s)
Breast Neoplasms/diagnosis , Breast Neoplasms/psychology , Mammography/psychology , Patient Acceptance of Health Care/psychology , Aged , Biopsy, Fine-Needle , Breast Neoplasms/pathology , Denmark , False Positive Reactions , Female , Humans , Mass Screening/methods , Mass Screening/psychology , Middle Aged
20.
Pharm Dev Technol ; 13(2): 93-104, 2008.
Article in English | MEDLINE | ID: mdl-18379901

ABSTRACT

This study was dedicated to facilitate scale-up in spray drying from an atomization standpoint. The purpose was to investigate differences in operating conditions between a pilot and a production scale nozzle. The intension was to identify the operating ranges in which the two nozzles produced similar droplet size distributions. Furthermore, method optimization and validation were also covered. Externally mixing two-fluid nozzles of similar designs were used in this study. Both nozzles are typically used in commercially available spray dryers, and they have been characterized with respect to droplet size distributions as a function of liquid type, liquid flow rate, atomization gas flow rate, liquid orifice diameter, and atomization gas orifice diameter. All droplet size measurements were carried out by using the Malvern Spraytec with nozzle operating conditions corresponding to typical settings for spray drying. This gave droplets with Sauter Mean Diameters less than 40 microm and typically 5-20 microm. A model previously proposed by Mansour and Chigier was used to correlate the droplet size to the operating parameters. It was possible to make a correlation for water incorporating the droplet sizes for both the pilot scale and the production scale nozzle. However, a single correlation was not able to account properly for the physical properties of the liquid to be atomized. Therefore, the droplet size distributions of ethanol could not be adequately predicted on the basis of the water data. This study has shown that it was possible to scale up from a pilot to production scale nozzle in a systematic fashion. However, a prerequisite was that the nozzles were geometrically similar. When externally mixing two-fluid nozzles are used as atomizers, the results obtained from this study could be a useful guideline for selecting appropriate operating conditions when scaling up the spray-drying process.


Subject(s)
Nebulizers and Vaporizers , Technology, Pharmaceutical , Particle Size
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