Developing paediatric medicines: identifying the needs and recognizing the challenges

There is a significant need for research and development into paediatric medicines. Only a small fraction of the drugs marketed and utilized as therapeutic agents in children have been clinically evaluated. The majority of marketed drugs are either not labelled, or inadequately labelled, for use in paediatric patients. The absence of suitable medicines or critical safety and efficacy information poses significant risks to a particularly vulnerable patient population. However, there are many challenges associated with developing medicines for the paediatric population and this review paper is intended to highlight these. The paediatric population is made up of a wide range of individuals of substantially varied physical size, weight and stage of physiological development. Experimentation on children is considered by many to be unethical, resulting in difficulties in obtaining critical safety data. Clinical trials are subject to detailed scrutiny by the various regulatory bodies who have recently recognized the need for pharmaceutical companies to invest in paediatric medicines. The costs associated with paediatric product development could result in poor or negative return on investment and so incentives have been proposed by the EU and US regulatory bodies. Additionally, some commonly used excipients may be unsuitable for use in children; and some dosage forms may be undesirable to the paediatric population.     

Selection of excipients for melt extrusion with two poorly water-soluble drugs by solubility parameter calculation and thermal analysis

The aim of this study was to determine the miscibility of drug and excipient to predict if glass solutions are likely to form when drug and excipient are melt extruded. Two poorly water-soluble drugs, indomethacin and lacidipine, were selected along with 11 excipients (polymeric and non-polymeric). Estimation of drug/excipient miscibility was performed using a combination of the Hoy and Hoftzyer/Van Krevelen methods for Hansen solubility parameter calculation. Miscibility was experimentally investigated with differential scanning calorimetry (DSC) and hot stage microscopy (HSM). Studies were performed at drug/excipient ratios, 1:4, 1:1 and 4:1. Analysis of the glass transition temperature (T(g)) was performed by quench cooling drug/excipient melts in the DSC. Differences in the drug/excipient solubility parameters of <7.0 MPa(1/2) were predicted to indicate significant miscibility and, therefore, glass solution formation on melt extrusion. In comparison, differences of >10 MPa(1/2) were expected to indicate a lack of miscibility and not form glass solutions when melt extruded. Experimentally, miscibility was shown by changes in drug/excipient melting endotherms and confirmed by HSM investigations. Experimental results were in agreement with solubility parameter predictions. In addition, drug/excipient combinations predicted to be largely immiscible often exhibited more than one T(g) upon reheating in the DSC. Melt extrusion of miscible components resulted in amorphous solid solution formation, whereas extrusion of an "immiscible" component led to amorphous drug dispersed in crystalline excipient. In conclusion, combining calculation of Hansen solubility parameters with thermal analysis of drug/excipient miscibility can be successfully applied to predict formation of glass solutions with melt extrusion.     

Do not say ever never more: the ins and outs of antiangiogenic therapies

Angiogenesis has been described as one of the hallmarks of cancer, playing an essential role in tumor growth, invasion, and metastasis. Antiangiogenic therapy was initially perceived as a "magic bullet" that could eventually be used for the treatment of any type of cancer. For this reason inhibition of angiogenesis has become a major challenge in the development of new anticancer agents, with a countless number of antiangiogenic strategies being tested in preclinical and clinical trials. The initial pessimism about the usefulness of the antiangiogenic therapeutic approach for cancer, derived from the poor results obtained in clinical trials, turned into euphoria after the approvals of the anti-VEGF monoclonal antibody bevacizumab and the multitargeted tyrosine kinase inhibitors sunitinib, sorafenib and pazopanib. Nowadays the clinical development of antiangiogenic therapies seems to be unstoppable, not only for cancer, but also for an increasing number of non-neoplasic angiogenesis-related diseases. Nevertheless, careful analysis of the clinical results reveals that therapy with angiogenesis inhibitors often does not prolong survival of cancer patients for more than months. This fact, combined with the high prices of the new antiangiogenic therapies have made a number of oncologists to doubt if they offer "good value". Moreover, recent experimental findings suggest that some antiangiogenic drugs could promote tumor invasiveness and metastasis. The success in the discovery and pharmacological development of future generations of angiogenesis inhibitors will benefit from further advances in the understanding of the mechanisms involved in human angiogenesis.     

European medicines and feed additives regulation are not in compliance with environmental legislation and policy

Environmental legislations for water and soil aim at the protection of quality of these compartments. This legislation has major consequences for product registration, amongst others the setting of environmental quality standards. A thorough risk assessment at registration of all products is crucial for the proper operationalisation of the environmental policy. A regulatory problem arises when the registration procedure is harmonised at a European level by the communautarian authority, while the authorities at the national level are responsible for maintaining the desired environmental quality. This problem can be tackled in two ways: firstly, the environmental risk assessment (ERA) should be based on common principles based on EU regulations and policy that steer the national authorities; secondly, the ERA should be developed under the supervision of competent authorities. Both options are not reflected in the forging of the ERA for medicines and feed additives. The formalisation of the contents and the procedure is not transparent nor open to input by scientists and other interested parties; the formalisation has no legal status, and European legislation cannot provide common protection goals in a global setting. The VICH Phase I and the EMEA Phase II guidance do not contain all communautarian environmental quality criteria, nor clear acceptability standards, nor harmonised methodology. Assessments are not made for all products, and the decision-making principles and practical procedures are not operational. It is therefore unlikely that any result of an ERA can be taken into consideration at registration, which undermines the legitimacy of the process. Both applicants and assessors are uncertain how to perform the risk assessment. The current developments may ultimately not only compromise product availability but also fail to protect the environment.     

Case studies with new excipients: development, implementation and regulatory approval

The purpose of this article is to describe the process whereby new excipients become accepted and to describe three case studies to illustrate the process. New excipients are defined according to the 2005 FDA Guidance on Nonclinical Safety Evaluation of New Excipients. The requirements for safety data submission for new excipients used in different classes of products for different durations are outlined in the guidance. Currently, the development of new excipients is linked to the development and approval of new drug products that contain them. New excipients that are used in US-approved drug products become listed in the FDA Inactive Ingredients Guide (IIG) database. Thereafter, US Pharmacopeia monographs for the new excipients are proposed. New excipients are reviewed and become accepted in the same way in Europe and Japan, except that there is no equivalent IIG database. Therefore, the focus of this article will be on the FDA review process. Three case studies, polyoxyl 15 hydroxystearate, sulfobutyl ether cyclodextrin and silicified microcrystalline cellulose, are used to illustrate how new excipients are accepted and implemented.     

Development of a rapidly dispersing tablet of a poorly wettable compound: formulation DOE and mechanistic study of effect of formulation excipients on wetting of celecoxib

Celecoxib has extremely poor aqueous wettability and dispersibility. A dispersibility method was developed to study the effects of formulation excipients and processing methods on wetting of celecoxib. In this method, a tablet or powder was placed in water and the turbidity of the resulting "dynamic" suspension was measured. Higher turbidity values reflect better dispersibility. Results show that wet granulation facilitates better drug dispersion than does dry granulation or direct compression. Results from a screening formulation statistical design of experiments (DOE) show that sodium lauryl sulfate (SLS), an anionic surfactant, gives higher celecoxib dispersibility than polysorbate 80, a neutral surfactant. Polyplasdone XL as a disintegrant results in better celecoxib dispersibility than sodium starch glycolate. The binder Kollidon 30 leads to better dispersibility, but slower disintegration than Kollidon 12. Jet-milling celecoxib with excipients not only improves dispersibility of the drug but also the ease of material handling. The method of microcrystalline cellulose addition does not significantly impact tablet properties. The effect of critical formulation variables on the wettability of celecoxib was further examined in prototype formulations. It is found that ionic surfactant resulted in better dispersibility than a neutral surfactant, probably due to charge dispersion. Kollidon 30 gives better drug dispersion than hydroxypropylmethyl cellulose and hydroxypropyl cellulose. This may be explained through a surface energy calculation, where the spreading coefficients between Kollidon 30 and celecoxib indicate formation of open porous granules in which pores can facilitate water uptake. The mode of disintegrant addition also impacts dispersibility of the drug. Dense granules were formed when the disintegrant, Polyplasdone, was added intra-granularly. As the extra-granular portion of the disintegrant increases, the dispersibility of the drug increases as well. The drug initial dispersibility (turbidity at 5 min during the dispersibility test) increases as the tablet porosity increases. A 3-factor face-centered experimental design was conducted to optimize the levels of surfactant (SLS), binder (Kollidon 30) and disintegrant (Polyplasdone). Within the range that was studied, the dispersibility of micronized drug increases as the amount of SLS and Kollidon 30 increases. The level of Polyplasdone has no significant impact on the dispersibility of micronized drug; however, higher levels of Polyplasdone lead to significantly harder tablets.     

家庭小药箱"储备四环素过期、变质引起急性中毒不容忽视

随着人们自我保健意识的增强和个人素质的提高,相当多的家庭设立了"小药箱",在治疗小伤小病时的确起到了有备无患的作用.但由于家庭药品储存品种越来越多,数量越来越大,加上没有定期清理或储存不当,很多药品在不经意间过期或变质.如果继续服用,不但起不到治疗疾病的作用,还有可能会延误患者病情,造成新的危害.如四环素是家庭常备的抗微生物药物,在储存过程中,一旦超过有效期,有害降解产物会不断增加,易引起严重危害.现将过期、劣质四环素临床急性中毒的特点综述如下.     

Interactions of formulation excipients with proteins in solution and in the dried state

A variety of excipients are used to stabilize proteins, suppress protein aggregation, reduce surface adsorption, or to simply provide physiological osmolality. The stabilizers encompass a wide variety of molecules including sugars, salts, polymers, surfactants, and amino acids, in particular arginine. The effects of these excipients on protein stability in solution are mainly caused by their interaction with the protein and the container surface, and most importantly with water. Some excipients stabilize proteins in solution by direct binding, while others use a number of fundamentally different mechanisms that involve indirect interactions. In the dry state, any effects that the excipients confer to proteins through their interactions with water are irrelevant, as water is no longer present. Rather, the excipients stabilize proteins through direct binding and their effects on the physical properties of the dried powder. This review will describe a number of mechanisms by which the excipients interact with proteins in solution and with various interfaces, and their effects on the physical properties of the dried protein structure, and explain how the various interaction forces are related to their observed effects on protein stability.     

Europe and medicines: role of the EMEA

F. Sauer. Ann Pharm Fr 2000, 58: 278-285. The new European authorization system has made considerable progress since 1995. The European Agency for the Evaluation of Medicinal Products (EMEA) is primarily responsible for the scientific evaluation of applications for a European marketing authorization for medicinal products derived from biotechnology and other high technology (centralised procedure). For other products, the EMEA arbitrates where mutual recognition of national marketing authorizations between the Member States is not possible (decentralised procedure). The EMEA co-ordinates the scientific resources made available by the national competent authorities of the Member States, including a network of over 2 000 European experts. The Opinions of the scientific committees of the EMEA (Committee for Proprietary Medicinal Products, CPMP, and Committee for Veterinary Medicinal Products, CVMP) are enforced by the European Commission, which has so far authorized 69 medicinal products for human and veterinary use. The confidence of industry, health professionals and consumers in the system is clear. European patients are now able to have speedier access to new drugs, usually within one year. The new system also helps to reinforce the safety of medicines for humans and animals, particularly through a pharmacovigilance network and the establishment of safe limits for residues in food-producing animals.     

挤出-滚圆法制备微丸的设备和辅料研究进展

随着机械设备的发展,微丸制备方法逐渐呈现出多样化趋势,而挤出-滚圆法是最为常用的一种制备微丸的方法。目前,微晶纤维素是挤出-滚圆法制备微丸的标准辅料,与此同时,正在不断研究和推出针对微晶纤维素微丸现存问题的其他替代性辅料,以期达到减少或完全替代微晶纤维素的目的。具有优良性质的通用型高载药量辅料是今后研究的方向。本文总结并阐述挤出-滚圆法所用的生产设备和辅料概况。     

Interaction between the photosensitizer lumichrome and human serum albumin: effect of excipients

Lumichrome (Lc) is a photodegradation product of riboflavin that can be used as a photosensitizer (PS) in antibacterial photodynamic therapy (aPDT). The binding of Lc with plasma proteins such as human serum albumin (HSA) could affect its efficiency as PS. Excipients are necessary to prepare stable formulations to be used in aPDT and they may affect the PS-HSA binding. Hydroxypropyl (HP)-α, β, γ-cyclodextrin (CD), polyethylene glycol 400 (PEG400) and Pluronic^® F-127 (PF127) were selected as model excipients in this study. The intrinsic HSA fluorescence quenching and absorption and fluorescence spectroscopy were used to evaluate the Lc-HSA interaction in the absence and presence of excipients. Nano-differential scanning calorimetry (DSC) was used to determine the effect of excipients on HSA. The photostability of the samples was also evaluated. The combined results showed a modest interaction between Lc and HSA which was reduced mainly by HPβCD. No major alterations of the HSA nano-DSC thermogram were observed after addition of excipients. HSA did enhance Lc photodegradation. The presence of PF127 did also induce photochemical destabilization of Lc independent of HSA. In conclusion, HPαCD, HPγCD and PEG400 seemed to be the excipients more suitable for use in topical preparations containing Lc.