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Zulbeari N, Holm R. Is roller milling - the low energy wet bead media milling - a reproducible and robust milling method for formulation investigation of aqueous suspensions? Int J Pharm 2024; 651:123733. [PMID: 38142873 DOI: 10.1016/j.ijpharm.2023.123733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 12/11/2023] [Accepted: 12/20/2023] [Indexed: 12/26/2023]
Abstract
Long-acting injectables have shown to offer a prolonged release of a drug compound up to several months, providing the opportunity to increase patient compliance for treatment of long-term and chronic conditions. Different formulation technologies have already been utilized for long-acting injectables, and especially aqueous suspensions with crystalline drug particles in the sub-micron range have sparked an interest for future development of long-acting injectables. Wet bead milling is a common top-down process used to prepare nano- and microsuspensions of crystalline drug particles with the addition of surfactants in the dispersion medium, which are working as stabilizers to prevent agglomeration or crystal growth that ultimately may influence the physical stability of nano- and microsuspensions. To examine the reproducibility of the suspensions manufactured and the behavior of their physical stability, i.e., changes in particle sizes over time, low-energy roller mill was utilized for the manufacturing of nano- and microsuspensions in the present study. Investigated formulation parameters was stabilizer type and concentration and milling parameters varied in bead size and duration of milling. The obtained results demonstrated that the physical stability of suspensions containing the two model compounds, cinnarizine and indomethacin, was highly affected by the constitution of surfactant and processing. Various size classes were obtained and accompanied by high variations between the individual samples that indicated uneven and unpredictable milling by the low-energy roller mill, limiting the possibility to prepare reproducible and physical stable suspensions. Short-term stability studies revealed clear tendencies towards reversed Ostwald ripening of suspensions stabilized with poloxamer 188 that contained cinnarizine as the drug compound, and to a smaller extent suspensions containing indomethacin. Furthermore, X-ray Powder Diffraction confirmed no alteration of the drug compounds crystal structure after roller milling for multiple days.
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Affiliation(s)
- Nadina Zulbeari
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark
| | - René Holm
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense, Denmark.
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Holm R, Lee RW, Glassco J, DiFranco N, Bao Q, Burgess DJ, Lukacova V, Alidori S. Long-Acting Injectable Aqueous Suspensions-Summary From an AAPS Workshop. AAPS J 2023; 25:49. [PMID: 37118621 DOI: 10.1208/s12248-023-00811-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 04/12/2023] [Indexed: 04/30/2023] Open
Abstract
Through many years of clinical application of long-acting injectables, there is clear proof that this type of formulation does not just provide the patient with convenience, but more importantly a more effective treatment of the medication provided. The formulation approach therefore contains huge untapped potential to improve the quality of life of many patients with a variety of different diseases. This review provides a summary of some of the central talks provided at the workshop with focus on aqueous suspensions and their use as a long-acting injectable. Elements as formulation, manufacturing, in vitro dissolution methods, in vitro and in vivo correlation, in silico modelling provide an insight into some of the current understandings, learnings, and not least gaps in the field.
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Affiliation(s)
- René Holm
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
| | - Robert W Lee
- Lubrizol Life Science, Health, CDMO Division, 3894 Courtney St., Bethlehem, Pennsylvania, 18017, USA
| | - Joey Glassco
- Lubrizol Life Science, Health: 9911 Brecksville Road, Cleveland, Ohio, 44141, USA
| | - Nicholas DiFranco
- Lubrizol Life Science, Health: 9911 Brecksville Road, Cleveland, Ohio, 44141, USA
| | - Quanying Bao
- School of Pharmacy, University of Connecticut, Storrs, Connecticut, 06269, USA
| | - Diane J Burgess
- School of Pharmacy, University of Connecticut, Storrs, Connecticut, 06269, USA
| | - Viera Lukacova
- Simulations Plus, Inc., 42505 10Th Street, Lancaster, California, 93534, USA
| | - Simone Alidori
- GlaxoSmithKline, 1250 S Collegeville Rd, Collegeville, Pennsylvania, 19426-2990, USA
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Elibal F, Gumustekin S, Ozkazanc H, Ozkazanc E. Poly(N-methylpyrrole) with high antibacterial activity synthesized via interfacial polymerization method. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130712] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Shedding a light on the physical stability of suspensions micronised with intensified vibratory milling; A trend observed with decreasing particle size as a function of time. Int J Pharm 2021; 603:120687. [PMID: 33965542 DOI: 10.1016/j.ijpharm.2021.120687] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/22/2021] [Accepted: 05/04/2021] [Indexed: 11/22/2022]
Abstract
Intensified vibratory milling is a nanonisation and micronisation technology which can be used to enable the oral bioavailability of poorly soluble compounds. The generated nano- and microsuspensions entail a large surface area which enhances the compounds dissolution rate, yet this large surface area is thermodynamically unfavourable and hence spontaneous destabilisation may occur, i.e. physical instability. Stability studies on suspensions manufactured via intensified vibratory milling have, to the best of our knowledge, not been reported in the literature before. An extended stability study was, therefore, executed with 30 bedaquiline suspensions milled with the intensified vibratory mill under various process settings. The particle size distribution was measured immediately after production, after four weeks of storage at 5 °C and after eleven weeks of storage at 5 °C with laser diffraction and scanning electron microscopy. In addition, a caking test was applied to scrutinise the redispersibility of the prevailing sediments. One sample whose sediment proved to be redisperible, demonstrated a peculiar trend during storage where a narrowing of the particle size distribution and a general particle size reduction was detected which opposed the conventional stability tendencies, i.e. stability or Ostwald ripening. This enigmatic trend was further explored via a repetitive analysis with laser diffraction and in a further phase, with an orthogonal particle sizing technique. Still, no matter the frequency nor technique, a narrowing particle size distribution was observed. To the best of our knowledge, this article, for the first time in the pharmaceutical literature, reports a narrowing particle size distribution of a micronised suspension containing an organic compound. Inevitably, this trend might shed a fundamental new light on the stability trends, exposed by suspensions post-micronisation by high energy milling.
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Park H, Ha ES, Kim MS. Physicochemical analysis techniques specialized in surface characterization of inhalable dry powders. JOURNAL OF PHARMACEUTICAL INVESTIGATION 2021. [DOI: 10.1007/s40005-021-00526-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Lee SH, Heng D, Teo JWP, Toh FKY, Tan RBH. Inhaled mucoactive particles with tailored architecture for enhanced aerodynamicity, stability and efficacy. Int J Pharm 2019; 572:118740. [PMID: 31648015 DOI: 10.1016/j.ijpharm.2019.118740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 09/23/2019] [Accepted: 09/25/2019] [Indexed: 10/25/2022]
Abstract
In respiratory and genetic disorders such as asthma, chronic obstructive pulmonary disease (COPD), chronic bronchitis and cystic fibrosis (CF), the lungs produce excess mucus, resulting in a thickened mass, which clogs up the airways and reduces airflow. Consequently, breathing becomes more difficult. Medications that break down the structure of mucus will be especially useful in managing the early symptoms of these diseases and preventing their progression into the more severe forms. This work therefore seeks to develop an inhaled mucoactive dry powder formulation that is efficacious on multiple fronts. As an innovative step, sodium chloride was used to tailor the surface architecture of ambroxol hydrochloride particles, such that the resulting angular features on the surfaces contributed to the creation of corrugated particles with enhanced aerodynamicity. The optimized spray-dried powder particles were of respirable-size (d50 of 2.85 ± 0.15 μm) and moderately corrugated. When the crystalline powder was dispersed via an Aerolizer® inhaler at 60 L/min, it gave a fine particle fraction (FPF) of ~31%, which was a ten-fold improvement over the unmodified species (i.e. ambroxol hydrochloride alone). Tests on artificial sputum medium (ASM) showed that the optimized formulation was potentially useful in liquefying the mucus, which favorably pointed towards the effectiveness of the formulation. In addition, the formulation was also stable to moisture ingress (up to ~60% RH) and had good flowability. Hence, the advent of angular adjuvant sodium chloride particles in a mucoactive formulation conferred a three-fold benefit to the product: (1) Improved aerodynamicity and flowability, (2) Enhanced moisture stability and (3) Synergistic mucolytic properties.
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Affiliation(s)
- Sie Huey Lee
- Institute of Chemical and Engineering Sciences, A*STAR (Agency for Science, Technology and Research), 1, Pesek Road, Jurong Island, Singapore 627833, Singapore
| | - Desmond Heng
- Institute of Chemical and Engineering Sciences, A*STAR (Agency for Science, Technology and Research), 1, Pesek Road, Jurong Island, Singapore 627833, Singapore.
| | - Jeanette W P Teo
- Department of Laboratory Medicine, National University Hospital, 5 Lower Kent Ridge Road, Singapore 119074, Singapore
| | - Frederick K Y Toh
- Institute of Chemical and Engineering Sciences, A*STAR (Agency for Science, Technology and Research), 1, Pesek Road, Jurong Island, Singapore 627833, Singapore
| | - Reginald B H Tan
- Institute of Chemical and Engineering Sciences, A*STAR (Agency for Science, Technology and Research), 1, Pesek Road, Jurong Island, Singapore 627833, Singapore; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576, Singapore.
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Yazdi AK, Smyth HD. Carrier-free high-dose dry powder inhaler formulation of ibuprofen: Physicochemical characterization and in vitro aerodynamic performance. Int J Pharm 2016; 511:403-414. [DOI: 10.1016/j.ijpharm.2016.06.061] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 06/20/2016] [Accepted: 06/24/2016] [Indexed: 11/28/2022]
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Anomalous size evolution of partially amorphized pharmaceutical particles during post-milling storage. POWDER TECHNOL 2015. [DOI: 10.1016/j.powtec.2015.08.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Depasquale R, Lee SL, Saluja B, Shur J, Price R. The influence of secondary processing on the structural relaxation dynamics of fluticasone propionate. AAPS PharmSciTech 2015; 16:589-600. [PMID: 25398478 DOI: 10.1208/s12249-014-0222-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 09/12/2014] [Indexed: 11/30/2022] Open
Abstract
This study investigated the structural relaxation of micronized fluticasone propionate (FP) under different lagering conditions and its influence on aerodynamic particle size distribution (APSD) of binary and tertiary carrier-based dry powder inhaler (DPI) formulations. Micronized FP was lagered under low humidity (LH 25 C, 33% RH [relative humidity]), high humidity (HH 25°C, 75% RH) for 30, 60, and 90 days, respectively, and high temperature (HT 60°C, 44% RH) for 14 days. Physicochemical, surface interfacial properties via cohesive-adhesive balance (CAB) measurements and amorphous disorder levels of the FP samples were characterized. Particle size, surface area, and rugosity suggested minimal morphological changes of the lagered FP samples, with the exception of the 90-day HH (HH90) sample. HH90 FP samples appeared to undergo surface reconstruction with a reduction in surface rugosity. LH and HH lagering reduced the levels of amorphous content over 90-day exposure, which influenced the CAB measurements with lactose monohydrate and salmeterol xinafoate (SX). CAB analysis suggested that LH and HH lagering led to different interfacial interactions with lactose monohydrate but an increasing adhesive affinity with SX. HT lagering led to no detectable levels of the amorphous disorder, resulting in an increase in the adhesive interaction with lactose monohydrate. APSD analysis suggested that the fine particle mass of FP and SX was affected by the lagering of the FP. In conclusion, environmental conditions during the lagering of FP may have a profound effect on physicochemical and interfacial properties as well as product performance of binary and tertiary carrier-based DPI formulations.
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Stability of nanosuspensions in drug delivery. J Control Release 2013; 172:1126-41. [PMID: 23954372 DOI: 10.1016/j.jconrel.2013.08.006] [Citation(s) in RCA: 295] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2013] [Revised: 07/31/2013] [Accepted: 08/06/2013] [Indexed: 01/28/2023]
Abstract
Nanosuspensions are nanosized colloidal dispersion systems that are stabilized by surfactants and/or polymers. Because nanosizing results in the creation of new interfaces and in a positive Gibbs free energy change, nanosuspensions are thermodynamically unstable systems with a tendency toward agglomeration or crystal growth. Despite extensive research on nanosuspension technology, stability remains a limitation for pharmaceutical or industrial applications of nanosuspensions. Furthermore, the empirical relationship between stabilizer efficacy and nanosuspension stability has not been well characterized. This review focuses on the issue of nanosuspension stability in drug delivery to present the state of the art of nanosuspensions. Therefore, this review will discuss unstable suspensions, methods and guidelines for selecting and optimizing stabilizers, approaches for enhancing stability, and other factors that influence nanosuspension stability. This review could serve as a reference for the educated selection of a stabilizer for a specific drug candidate and the optimization of the operational parameters for nanosuspension formulation, rather than the currently practiced trial-and-error approach.
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Gahoi S, Jain GK, Tripathi R, Pandey SK, Anwar M, Warsi MH, Singhal M, Khar RK, Ahmad FJ. Enhanced antimalarial activity of lumefantrine nanopowder prepared by wet-milling DYNO MILL technique. Colloids Surf B Biointerfaces 2012; 95:16-22. [DOI: 10.1016/j.colsurfb.2012.01.047] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 01/17/2012] [Accepted: 01/27/2012] [Indexed: 10/14/2022]
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Le V, Robins E, Flament M. Agglomerate behaviour of fluticasone propionate within dry powder inhaler formulations. Eur J Pharm Biopharm 2012; 80:596-603. [DOI: 10.1016/j.ejpb.2011.12.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 11/16/2011] [Accepted: 12/06/2011] [Indexed: 10/14/2022]
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Peltonen L, Hirvonen J. Pharmaceutical nanocrystals by nanomilling: critical process parameters, particle fracturing and stabilization methods. J Pharm Pharmacol 2011; 62:1569-79. [PMID: 21039542 DOI: 10.1111/j.2042-7158.2010.01022.x] [Citation(s) in RCA: 220] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
OBJECTIVES Wet milling is a common technique to produce drug nanocrystals. Stability of the nanocrystals is a critical question, and different kinds of stabilizers, e.g. polymers, celluloses, surfactants and lipids, have been tested for various drugs. Still, the question about how to select the best stabilizer to a certain drug material and also to a selected process is open. KEY FINDINGS Many different factors, such as surface energy, hydrophobicity, solubility, viscosity and functional groups, affect the stability of the formed nanosuspensions. Affinity of the stabilizer to the particle surfaces seems to be the most important parameter. This affinity is partly related to the surface energy and hydrophobicity of the surfaces and stabilizers. SUMMARY In this review the most important factors affecting nanocrystal formulation and efficacy of stabilizers are presented. In order to widen understanding of the milling process, the most important variables related to milling techniques and particle fracturing processes during the milling are briefly presented.
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Affiliation(s)
- Leena Peltonen
- Division of Pharmaceutical Technology, University of Helsinki, Finland.
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Royall P, Woodhead B, Tang S, Martin G, Stockton B, Murnane D. Formation and measurement of process induced disorder during the manufacture of inhalation medicines. J Drug Deliv Sci Technol 2011. [DOI: 10.1016/s1773-2247(11)50048-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Ng WK, Kwek JW, Yuen A, Tan CL, Tan R. Effect of milling on DSC thermogram of excipient adipic acid. AAPS PharmSciTech 2010; 11:159-67. [PMID: 20101483 DOI: 10.1208/s12249-009-9372-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2009] [Accepted: 12/17/2009] [Indexed: 11/30/2022] Open
Abstract
The purpose of this research was to investigate why and how mechanical milling results in an unexpected shift in differential scanning calorimetry (DSC) measured fusion enthalpy (Delta(fus)H) and melting point (T(m)) of adipic acid, a pharmaceutical excipient. Hyper differential scanning calorimetry (hyper-DSC) was used to characterize adipic acid before and after ball-milling. An experimental study was conducted to evaluate previous postulations such as electrostatic charging using the Faraday cage method, crystallinity loss using powder X-ray diffraction (PXRD), thermal annealing using DSC, impurities removal using thermal gravimetric analysis (TGA) and Karl Fischer titration. DSC thermograms showed that after milling, the values of Delta(fus)H and T(m) were increased by approximately 9% and 5 K, respectively. Previous suggestions of increased electrostatic attraction, change in particle size distribution, and thermal annealing during measurements did not explain the differences. Instead, theoretical analysis and experimental findings suggested that the residual solvent (water) plays a key role. Water entrapped as inclusions inside adipic acid during solution crystallization was partially evaporated by localized heating at the cleaved surfaces during milling. The correlation between the removal of water and melting properties measured was shown via drying and crystallization experiments. These findings show that milling can reduce residual solvent content and causes a shift in DSC results.
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Tanaka Y, Inkyo M, Yumoto R, Nagai J, Takano M, Nagata S. Nanoparticulation of poorly water soluble drugs using a wet-mill process and physicochemical properties of the nanopowders. Chem Pharm Bull (Tokyo) 2009; 57:1050-7. [PMID: 19801857 DOI: 10.1248/cpb.57.1050] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In order to improve the dissolution and oral absorption properties of poorly water soluble drugs such as omeprazole, albendazole and danazol, various dispersing agents were added to prepare nanopowder formulations using an ULTRA APEX MILL, which is a wet-mill instrument, and their physicochemical properties were evaluated. Using Pluronic F-108 or F-68 as dispersing agents, slurries containing drug particles having nanometer size were obtained for all model drugs tested. Omeprazole, a heat labile drug, was not degraded by wet-milling and the omeprazole nanoparticles in a milled slurry did not aggregate for 24 h after wet-milling. After lyophilization of these milled slurries containing drug nanoparticles, fine solid white nanopowders were obtained. Scanning electron microscopy (SEM) suggested that the model drugs were milled into nanometer size. X-ray powder diffraction (XRPD) patterns and Differential Scanning Calorimetry (DSC) curves confirmed that all milled drug nanopowders were crystalline, although milling of albendazole nanopowder transformed it to another crystal form. Wet-milling using an ULTRA APEX MILL offers a highly effective approach to produce stable drug nanopowders and is a very useful tool for bioavailability enhancement of poorly water soluble and heat labile drugs.
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Affiliation(s)
- Yusuke Tanaka
- Laboratory of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Hiroshima International University, Kure, Hiroshima 737-0112, Japan.
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Anomalous Particle Size Shift During Post-milling Storage. Pharm Res 2007; 25:1175-85. [DOI: 10.1007/s11095-007-9497-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Accepted: 11/06/2007] [Indexed: 11/25/2022]
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Abstract
Drug powders containing micron-size drug particles are used in several pharmaceutical dosage forms. Many drugs, especially newly developed substances, are poorly water soluble, which limits their oral bioavailability. The dissolution rate can be enhanced by using micronized drugs. Small drug particles are also required in administration forms, which require the drug in micron-size size due to geometric reasons in the organ to be targeted (e.g., drugs for pulmonary use). The common technique for the preparation of micron-size drugs is the mechanical comminution (e.g., by crushing, grinding, and milling) of previously formed larger particles. In spite of the widespread use of this technique, the milling process does not represent the ideal way for the production of small particles because drug substance properties and surface properties are altered in a mainly uncontrolled manner. Thus, techniques that prepare the drug directly in the required particle size are of interest. Because physicochemical drug powder properties are decisive for the manufacturing of a dosage form and for therapeutic success, the characterization of the particle surface and powder properties plays an important role. This article summarizes common and novel techniques for the production of a drug in small particle size. The properties of the resulting products that are obtained by different techniques are characterized and compared.
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Affiliation(s)
- Norbert Rasenack
- Department of Pharmaceutics and Biopharmaceutics, Christian Albrecht University Kiel, Kiel, Germany
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Steckel H, Pichert L, Müller BW. Influence of process parameters in the ASES process on particle properties of budesonide for pulmonary delivery. Eur J Pharm Biopharm 2004; 57:507-12. [PMID: 15093600 DOI: 10.1016/j.ejpb.2004.01.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2003] [Revised: 01/12/2004] [Accepted: 01/20/2004] [Indexed: 11/24/2022]
Abstract
Budesonide was micronized by precipitation in supercritical carbon dioxide by using the aerosol solvent extraction system at various process conditions. The process is characterised by spraying an organic solution of budesonide into the supercritical fluid (SCF), precipitation of the drug in the SCF and extraction and recovery of the solvent. The micronized budesonide particles were characterized physico-chemically for their morphology, crystallinity, size distribution and for their aerodynamic behaviour. The particle size distribution of the powder products was similar, regardless of the process conditions used for the crystallization. Also, the morphology of the particles did not differ between the batches. However, the aerodynamic properties of the precipitated batches were significantly different between the batches produced and as compared to a jet-milled budesonide powder. In conclusion, the process conditions in the SCF precipitation may influence the aerodynamic properties, although other physico-chemical parameters appear to be similar.
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Affiliation(s)
- Hartwig Steckel
- Department of Pharmaceutics and Biopharmaceutics, Christian Albrecht University Kiel, Kiel, Germany.
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Wang RB, Kuo CL, Lien LL, Lien EJ. Structure-activity relationship: analyses of p-glycoprotein substrates and inhibitors. J Clin Pharm Ther 2003; 28:203-28. [PMID: 12795780 DOI: 10.1046/j.1365-2710.2003.00487.x] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE A large number of structurally and functionally diverse compounds act as substrates or modulators of p-glycoprotein (p-gp). Some of them possess multiple drug resistance (MDR)-reversing activity, but only a small number of them have entered clinical study. In order to uncover the factors which exert a significant impact on the interaction between substrates/modulators and p-gp, we have performed structure-activity relationship (SAR) analyses, including molecular modelling, two-dimensional (2D) and three-dimensional (3D) parameter-frame-setting analysis, quantitative structure activity relationship (QSAR) analysis among substrates/modulators, as well as clinically promising MDR-reversing agents. METHODS The physicochemical parameters C log P, CMR and all regression equations were derived by using C log P version 4.0 and the latest CQSAR software, respectively. Molecular modelling and all other parameter calculations were performed by using HyperChem version 5.0 program, after geometry optimization and energy minimization using the AM1 semiempirical method. RESULTS SAR analyses indicate that MDR reversal activity is correlated with the lipophilicity (C log P), molecular weight (log Mw), longest chain (Nlc) of the molecule and the energy of the highest occupied orbital (Ehomo). In addition, the presence of a basic tertiary nitrogen atom in the structure is also an important contributor to p-gp inhibitory activity. Some separation in space is achieved for different subsets of p-gp substrates and inhibitors using Nlc, C log P and Ehomo as three independent parameters in the 3D-parameter-frame setting. CONCLUSION A highly effective p-gp modulator candidate should possess a log P value of 2.92 or higher, 18-atom-long or longer molecular axis, and a high Ehomo value, as well as at least one tertiary basic nitrogen atom. The results obtained may be useful in explaining drug-p-gp interactions for different compounds, including drug interactions and the development of new MDR chemosensitizers.
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Affiliation(s)
- R B Wang
- School of Pharmacy, Shandong University, Jinan, People's Republic of China
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Rasenack N, Steckel H, Müller BW. Micronization of anti-inflammatory drugs for pulmonary delivery by a controlled crystallization process. J Pharm Sci 2003; 92:35-44. [PMID: 12486680 DOI: 10.1002/jps.10274] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Jet-milling as the common way for micronization of drugs shows several disadvantages. Drug powder properties are decisive for pulmonary use because, besides a small particle size, a good deagglomeration behavior is required. In this study, several anti-inflammatory drugs [beclomethasone-17,21-dipropionate (BDP), betamethasone-17-valerate (BV), triamcinolone acetonide, ECU-R2, budesonide, and prednisolone] were micronized by controlled crystallization without any milling processes. First the drug is dissolved in an organic solvent (BDP/BV: 4%; ECU-R2: 1% in acetone) and precipitated by a solvent change method in the presence of a cellulose ether (hydroxypropylmethylcellulose) as stabilizing hydrocolloid. By rapid pouring the solution of hydroxypropylmethylcellulose in water (BDP/BV: 0.005%; ECU-R2: 0.025%) into the drug solution under stirring in a relationship (v/v) of 1:16 (BDP/BV), 1:4 (ECU-R2), the previously molecularly dispersed drug was associated to small particles and stabilized against crystal growth simultaneously. This dispersion was spray-dried, resulting in a drug powder with a uniform particle-size distribution and a drug load of up to 98% (BDP, BV). The mean particle size of the drug was lower than 5 microm in most cases and consequently in the respirable range. Whereas the fine particle fraction (<5 microm, measured without excipients and without an inhalation device) of jet-milled drugs is 9.5 (BDP) or 13.1 (ECU-R2), fine particle fractions of 25.6% (BDP) resp. 78.2% (ECU-R2) are obtained with the spray-dried powders. As the formation of the small crystals requires a rapid solvent change process, the affinity of the hydrocolloid, and a high difference between the solubility in the solvent and nonsolvent, the drug's partition coefficient limits the method as drugs which are more hydrophilic form larger particles.
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Affiliation(s)
- Norbert Rasenack
- Department of Pharmaceutics and Biopharmaceutics, Christian Albrecht University Kiel, Gutenbergstr 76, D-24118 Kiel, Germany
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Rasenack N, Müller BW. Dissolution rate enhancement by in situ micronization of poorly water-soluble drugs. Pharm Res 2002; 19:1894-900. [PMID: 12523671 DOI: 10.1023/a:1021410028371] [Citation(s) in RCA: 190] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE The purpose of this study was to evaluate a novel in situ micronization method avoiding any milling techniques to produce nano- or microsized drug particles by controlled crystallization to enhance the dissolution rate of poorly water-soluble drugs. METHODS Ibuprofen, itraconazole, and ketoconazole microcrystals were prepared by the association of the previously molecularly dispersed drug using a rapid solvent change process. The drug was precipitated in the presence of stabilizing agents, such as hydrocolloids. The obtained dispersion was spray-dried. Particle size, morphology, dissolution rate, specific surface area, and wettability were analyzed. Physicochemical properties were characterized using differential scanning calorimetry and X-ray diffractometry. RESULTS The obtained dispersions showed a homogeneous particle size distribution. Drugs are obtained in a mean particle size of approximately 2 microm and below. A high specific surface area was created and in situ stabilized. Different stabilizers showed differences in protecting the precipitated drug from crystal growth. The surface was hydrophilized because of the adsorbed stabilizer. Thus, a drug powder with markedly enhanced dissolution rate was obtained. CONCLUSIONS In situ micronization is a suitable method for the production of micro-sized drugs. This technique can be performed continuously or discontinuously and uses only common technical equipment. Compared to milled products drug properties are optimized as all particle surfaces are naturally grown, the particle size is more uniformly distributed and the powder is less cohesive.
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Affiliation(s)
- Norbert Rasenack
- Department of Pharmaceutics and Biopharmaceutics, Christiain Albrecht University Kiel, Gutenbergstr. 76, 24118 Kiel, Germany
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