Spray-Coating for Biopharmaceutical Powder Formulations: Beyond the Conventional Scale and Its Application

PURPOSE: Fluid-bed spray-coating process is widely used to prepare non-protein pharmaceutical solid dosage forms using macro-size seed particles (200-1000 microm) at kilogram batch sizes. In this study we developed a small-scale fluid-bed spray-coating process (20 g) to produce micro-sized vaccine powder formulations (40-60 microm) for epidermal powder immunization (EPI) METHODS: A bench-top spray coater was used to spray two vaccines, diphtheria toxoid (dT) and alum-adsorbed hepatitis-B surface antigen (Alum-HBsAg), onto crystalline lactose particles of 40-60 microm in diameter. Particle properties such as particle size, surface morphology, and degree of particle agglomeration were determined. Protein stability was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The immunogenicity of the vaccine was evaluated in vivo by needle injection and epidermal powder immunization (EPI) of mice or guinea pigs. RESULTS: Coating feasibility was demonstrated for both vaccine formulations containing different excipients. However, the nature of the vaccine antigen appeared to affect coating feasibility in terms of particle agglomeration considerably. Delivery of spray-coated dT and alum-HBsAg through EPI to mice and guinea pigs, respectively, generated significant antibody responses, at a level comparable to liquid formulation delivered subcutaneously through needle/syringe injection. CONCLUSIONS: The new spray-coating process represents an important technical advance and may provide a useful tool for developing high-valued biopharmaceutical powder formulations for novel applications. The strong in vivo performance of the coated dT and alum-HBsAg powders by EPI further demonstrated that spray-coating is a viable dry powder formulation process and the skin's epidermal layer presents an efficient vaccine delivery route.     

Development of a Stable Liquid Formulation for Live Attenuated Influenza Vaccine

Live attenuated influenza vaccine (LAIV) is considered one of the most effective vaccines and can be manufactured quickly and inexpensively to counter seasonal or pandemic influenza. Lyophilization is widely used in vaccine production. However, it requires a longer production cycle and large-scale equipment, thus posing a considerable financial burden for developing countries. A potential solution is the development of liquid LAIV, which can increase the yield and reduce the cost of production. In this study, influential factors of LAIV, such as potential stabilizing excipients and pH, were optimized by an orthogonal design. We found that pH is the most critical factor for the stability of LAIV; salt concentration and initial virus titer are also important for LAIV stability. With these data, we developed a liquid formulation consisting of 2.5% sucrose, 0.1% monosodium glutamate, 1% arginine, and 0.5% human serum albumin, with pH ranging from 6.2 to 6.9 (optimum pH 6.5-6.7), for optimal production of monovalent or trivalent LAIVs. This liquid formulation has the potential to considerably improve vaccine production capacity to compensate for the immense shortfall in influenza vaccines globally.     

丁香苦苷冻干粉针的处方优化及制备工艺的研究

目的:研究适合注射用丁香苦苷冻干粉针的处方配比和制备工艺。方法:以产品外观,复水性,含量等为指标,运用正交试验法优化其处方配比;采用真空冷冻干燥法制备其样品,用高效液相色谱法检测其含量,并对制备条件如装量、共晶点、预冻温度、升华温度、解吸温度等进行研究。结果:经优化,确定丁香苦苷含量为8%(A2),赋形剂用量为5%甘露醇(B2),装量为2.5mL(C3),西林瓶规格为7mL(D1);生产工艺为pH值为7.0,-45℃下预冻、-30℃下升华干燥和25℃时解吸干燥。结论:该工艺制备的丁香苦苷冻干粉针符合《中国药典》(2005版)冻干粉针的相关规定。     

Concentration Determination of a Recombinant Vaccine Antigen Adsorbed onto an Alum Adjuvant by Chemiluminescent Nitrogen Detection

No HeadingPurpose. A chemiluminescent nitrogen detector (CLND) has been evaluated for determining the concentration of an aluminum-adsorbed recombinant vaccine antigen.Methods. Quantification of the antigen was based upon several nitrogen-containing compounds used to calibrate the CLND. All calibrants (6.75–400 g/ml) generated linear standard curves, with slopes being directly proportional to the % nitrogen. The limit of quantification (LOQ) was determined to be 6.75 g/ml based on the performance of the antigen standard curve, and the limit of detection (LOD) was defined by setting the CLND minimum peak area to 40,000 U. The CLND was capable of analyzing antigen-adjuvant suspensions (adsorbed + unbound antigen) without any sample pretreatment. To measure unbound antigen, the suspension was centrifuged and an aliquot of supernatant removed for analysis; the difference between these two measurements was the amount of adsorbed antigen.Results. The adjuvant exhibited no significant matrix effect. Samples were analyzed in triplicate with observed relative standard deviation values ranging from 0.065% to 10.0%. The most accurate concentrations of the antigen were recovered relative to the antigen itself and to glycine as standards.Conclusion. This methodology provides a direct measurement of the concentration of a vaccine antigen adsorbed onto an aluminum adjuvant.     

Structural Characterization and Formulation Development of a Trivalent Equine Encephalitis Virus-Like Particle Vaccine Candidate

The zoonotic equine encephalitis viruses (EEVs) can cause debilitating and life-threatening disease, leading to ongoing vaccine development efforts for an effective virus-like particle (VLP) vaccine based on 3 strains of EEV (Eastern, Western, and Venezuelan or EEE, WEE and VEE VLPs, respectively). In this work, transmission electron microscopy and light scattering studies showed enveloped, spherical, and ～70 nm sized VLPs. Biophysical studies demonstrated optimal VLP physical stability in the pH range of 7.5-8.5 and at temperatures below ～50°C. Interestingly, the individual stability profiles differed notably between the 3 VLPs. Numerous pharmaceutical excipients were screened for their VLP stabilizing effects against thermal stress. Sucrose, sorbitol, sodium chloride, and pluronic F-68 were identified as promising stabilizers and the concentrations and combinations of these additives were optimized. Candidate monovalent VLP bulk formulations were incubated at temperatures ranging from ?80°C to 40°C to establish freeze-thaw, long-term (2°C-8°C) and accelerated stability trends. Good VLP stability profiles were observed at each storage temperature, except for a distinct instability observed at ?20°C. The interaction of monovalent and trivalent VLP formulations with aluminum adjuvants was examined, both in terms of antigen adsorption and desorption over time. The implications of these findings on future vaccine formulation development of EEV VLPs are discussed.     

Insoluble Powder Formulation as an Effective Nasal Drug Delivery System

Purpose. To evaluate the utility of insoluble powder formulation for nasal systemic drug delivery. Methods. To compare the efficacy of liquid and powder formulations, the nasal absorption of drugs was examined in rats using hydrophilic compounds with various molecular weights (MW) such as phenol red, cyanocobalamin, and fluorescein isothiocyanate (FITC)-Dextrans, and several kinds of powder. Intranasal residence time was also compared among the different formulations. Results. All the drugs examined were absorbed through the nasal mucosa to varying extent; their systemic bioavailability decreased with increasing MW. Insoluble calcium carbonate (CaCO₃) powder formulation provided increased absorption of drugs over the wide range of MW from 354 to 77,000 Da. In the case of phenol red, intranasal administration as a CaCO₃ powder formulation resulted in a plasma concentration profile similar to that of an intravenous bolus dose due to its very rapid and complete absorption from the nasal cavity. Furthermore, improved bioavailability of FITC-Dextran (MW 4,400; FD-4) was also achieved with other insoluble powders as well as CaCO₃, but not with soluble powders such as lactose, d-sorbitol, and d-mannitol. Insoluble powder formulation prolonged the residence time of FD-4 within the nasal cavity. Conclusions. Insoluble powder formulations improve nasal bioavailability predominantly by retarding drug elimination from the absorption site and appear to be effective for nasal systemic drug delivery.     

Characterization of the MN gp120 HIV-1 Vaccine: Antigen Binding to Alum

Purpose. The characterization of recombinant MN gp120/alum vaccine requires the study of the gp120-alum interaction for the successful formulation of an alum-based HIV-1 vaccine. Methods. Several observations suggest that the gpl20-alum interaction is weak, wherein buffer counterions such as phosphate, sulfate, bicarbonate may cause the desorption of gp120 from alum. Comparison of gp120 with other proteins using particle mobility measurements shows that the weak binding of gp120 to alum is not an anomaly. Serum and plasma also cause desorption of gp120 from alum with a half-life of only a few minutes, wherein this half-life may be faster than the in-vivo recruitment of antigen presenting cells to the site of immunization. Results. Immunization of guinea pigs, rabbits and baboons with gp120 formulated in alum or saline demonstrated that alum provides adjuvant activity for gp120, particularly after early immunizations, but the adjuvant effect is attenuated after several boosts. Conclusions. These observations indicate that both the antigen and the adjuvant require optimization together.     

Immunopotentiation and Delivery Systems for Antigens for Single-Step Immunization: Recent Trends and Progress

The use of adjuvants for immunopotentiation has been investigated since the 1920s and a number of comprehensive reviews and monographs have been published on this subject. A recent trend in immunopotentiation has been the use of delivery systems which allow for sustained or controlled release of antigens and which induce prolonged immunity following a single dose. This concept has been termed either single-step or single-shot immunization. The delivery system has been modulated to potentiate the immune response either by delivering the antigen (and perhaps an adjuvant or adjuvants) either over a prolonged period of time or in a predetermined sequence or by incorporating substances with immunoadjuvant properties (e.g., lecithin and certain biodegradable polymers) as carriers within the delivery system. This Review focuses on the progress made in the design of delivery systems for immunopotentiation. Particular emphasis is given to delivery systems designed to achieve single-step immunization.     

Formulation and Characterization of Lipid-Coated Tobramycin Particles for Dry Powder Inhalation

Purpose This study was conducted to develop and evaluate the physicochemical and aerodynamic characteristics of lipid-coated dry powder formulations presenting particularly high lung deposition. Methods Lipid-coated particles were prepared by spray-drying suspensions with different concentrations of tobramycin and lipids. The solid-state properties of the formulations, including particle size and morphology, were assessed by scanning electron microscopy and laser diffraction. Aerosol performance was studied by dispersing the powders into a Multistage Liquid Impinger and determining drug deposition by high-performance liquid chromatography. Results Particle size distributions of the formulations were unimodal, narrow with more than 90% of the particles having a diameter of less than 2.8 μm. All powder formulations exhibited mass median diameters of less than 1.3 and 3.2 μm, as determined by two different laser diffraction methods, the Malvern's Mastersizer? and Spraytec?, respectively. The fine particle fraction varied within a range of 50.5 and 68.3%. Conclusions Lipid coating of tobramycin formulations resulted in a reduced agglomeration tendency and in high fine particle fraction values, thus improving drug deposition. The very low excipients content (about 5% m/m) of these formulations offers the benefit of delivering particularly huge concentrations of antibiotic directly to the site of infection, while minimizing systemic exposure, and may provide a valuable alternative treatment of cystic fibrosis.     

A review of multiple approaches towards an improved hepatitis B vaccine

Background: Hepatitis B is a DNA virus that can cause liver inflammation, cirrhosis, and cancer in chronically infected and symptomatic carriers. Antiviral treatments are usually limited in their effectiveness in treating the disease states. Vaccination against hepatitis B in pediatric and adolescent populations has proven to be a generally effective means for preventing diseases that could be potentially caused by this virus. Some 5 – 10% of the vaccinees do not develop protective immunity against the virus. Therefore, a significant amount of effort has been made in many research laboratories across the world to increase the potency of the vaccine by various innovative means, e.g., increasing the immunogenicity of the antigen or through introduction of novel adjuvants that elicit strong humoral and cell-mediated immune responses. Objectives/methods: The objective of this review is to highlight publications of significant developments that have been made over the past decade and efforts that are continuing towards producing an improved vaccine. A number of patents that protect novel hepatitis B vaccine formulations, including those claiming novel hepatitis B core antigen formulations and combinations of a vaccine with small molecule therapeutics, are discussed. Conclusion: There have been promising developments in the area of new adjuvants and delivery systems. The practical need for reducing the total number of childhood vaccinations has driven development of, and patent filings on, multivalent and combination vaccine formulations in which the hepatitis B vaccine is included as one component. Efforts and some advances have also been made in the critical area of therapeutic application of the vaccine. The existence of a large population of already infected patients and the inadequacy of most of the current antiviral drugs against hepatitis B diseases have also inspired efforts to produce a vaccine that would be efficacious in clearing an exiting infection.     

Characterization of Murine Monoclonal Antibody to Tumor Necrosis Factor (TNF-MAb) Formulation for Freeze-Drying Cycle Development

Purpose. This study was designed to characterize the formulation of protein pharmaceuticals for freeze-drying cycle development. Thermal properties of a protein formulation in a freezing temperature range are important in the development of freezing and primary drying phases. Moisture sorption properties and the relationship between moisture and stability are the bases for the design of the secondary drying phase. Methods. We have characterized the formulation of TNF-MAb for the purpose of freeze-drying cycle development. The methods include: DTA with ER probes, freeze-drying microscopy, isothermal water adsorption, and moisture optimization.Results. The DTA/ER work demonstrated the tendency to noneutectic freezing for the TNF-MAb formulation at cooling rates of –1 to –3°C/min. The probability of glycine crystallization during freezing was quite low. A special treatment, either a high subzero temperature holding or annealing could promote the maximum crystallization of glycine, which could dramatically increase the T_g' of the remaining solution. The freeze-drying microscopy further indicated that, after the product was annealed, the cake structure was fully maintained at a T_p below –25°C during primary drying. The moisture optimization study demonstrated that a drier TNF-MAb product had better stability. Conclusions. An annealing treatment should be implemented in the freezing phase in order for TNF-MAb to be dried at a higher product temperature during primary drying. A secondary drying phase at an elevated temperature was necessary in order to achieve optimum moisture content in the final product.     

Formulation of Vaccine Adjuvant Muramyldipeptides. 3. Processing Optimization,Characterization, and Bioactivity of an Emulsion Vehicle

An efficacious vaccine adjuvant which elicits both cell-mediated immunity (CMI) and humoral immune response was developed using [thr¹-Muramyldipeptide (MDP) in an oil-in-water emulsion vehicle containing poloxamer 401, polysorbate 80, and squalane. Processing optimization was performed to increase the physical stability of this adjuvant emulsion which, when prepared by conventional mixing methods, demonstrated good bioactivity but poor physical stability. Various manufacturing methods were compared with a microfluidization process, which produced the most stable and elegant emulsion vehicle. The microfluidized emulsion also elicited equivalent biological response in the animal model tested.     

复方珍珠粉泡腾颗粒处方筛选及溶出度考察

目的:筛选复方珍珠粉泡腾颗粒处方并考察其在不同介质中的体外溶出度。方法:以乙二胺四乙酸消耗量为指标,兼顾发泡高度和pH值,用均匀设计法筛选处方中无水柠檬酸、碳酸氢钠、乳糖的量;考察并比较复方珍珠粉泡腾颗粒、自制碳酸钙片、自制珍珠粉片中碳酸钙在蒸馏水和盐酸中的溶出度。结果:处方中无水柠檬酸、碳酸氢钠、乳糖的量分别为10.0、2.5、5.0g;3种制剂间的溶出度有明显差异。结论:制备的复方珍珠粉泡腾颗粒释药速度快、药物溶出完全,溶液呈酸性,适合特定人群使用。     

Optimization of Primary Drying in Lyophilization During Early-Phase Drug Development Using a Definitive Screening Design With Formulation and Process Factors

Development of optimal drug product (DP) lyophilization cycles is typically accomplished via multiple engineering runs to determine appropriate process parameters. These runs require significant time and product investments, which are especially costly during early phase development when the DP formulation and lyophilization process are often defined simultaneously. Even small changes in the formulation may require a new set of engineering runs to define lyophilization process parameters. To overcome these development difficulties, an 8 factor definitive screening design, including both formulation and process parameters, was executed on a fully human monoclonal antibody DP. The definitive screening design enables evaluation of several interdependent factors to define critical parameters that affect primary drying time and product temperature. From these parameters, a lyophilization development model is defined where near optimal process parameters can be derived for many different DP formulations. This concept is demonstrated on a monoclonal antibody DP where statistically predicted cycle responses agree well with those measured experimentally. This design of experiments approach for early phase lyophilization cycle development offers a workflow that significantly decreases the development time of clinically and potentially commercially viable lyophilization cycles for a platform formulation that still has variable range of compositions.     

处方设计及冻干工艺对注射用盐酸吡柔比星稳定性的影响

目的 制备盐酸吡柔比星冻干制剂,考察处方设计及冻干工艺对产品质量的影响。方法 采用冻干工艺制备注射用吡柔比星,分别考察赋形剂种类和用量、中间体配液pH值控制及冻干曲线设计对吡柔比星稳定性的影响。结果 通过处方和工艺筛选,选择乳糖作为赋形剂,最优处方赋形剂用量为每瓶90 mg,最优成盐pH值为3.7～3.9,中间体pH控制范围在5.0~6.0内无显著性差异,预冻工艺选择先迅速降温至–50℃后再升温至–20℃,继续降温至–50℃的退火程序,2次干燥时间为600 min时产品水分为0.3%,继续延长时间水分不再下降。结论 通过处方和工艺筛选,确定了最优处方工艺。     

番石榴叶冻干粉针处方及工艺研究

目的确定番石榴叶冻干粉针的合理处方和制备工艺。方法选用适宜赋形剂，对处方进行筛选，用冷冻干燥法将其制备成冻干粉针，并对冻干粉针与注射液的稳定性进行初步考察。结果以甘露醇（8mg／mL）为支架剂、药液质量浓度为6mg／mL的处方较好，制成的冻干粉针质量比注射液更稳定。结论番石榴叶冻干粉针处方和工艺可行，质量稳定。     

Immune Augmentation of Single Contact Hepatitis B Vaccine by Using PLGA Microspheres as an Adjuvant

The present study was aimed to replace the alum type adjuvant for hepatitis B vaccine. The hepatitis B vaccine was encapsulated in poly (DL-lactide-co-glycolide) microspheres by solvent evaporation technique. The formulated microspheres were characterized in terms of morphology, particle size analysis, in vitro release study and in vivo immune response in male Wistar rats. The FT IR spectrum illustrates the characteristics bands of poly (DL-lactide-co-glycolide) microspheres and hepatitis B vaccine at 1750 cm^-1 and 1650 cm^-1, respectively. The hepatitis B vaccine loaded poly (DL-lactide-co-glycolide) microspheres were able to release antigens till day 42. Significant enhancement of specific antibodies to HBsAg was produced till day 90 after a single administration of HBsAg encapsulated poly (DL-lactide-co-glycolide) microspheres. However, the conventional alum adsorbed hepatitis B vaccine was not found to produce any significant specific antibody levels till day 90 after a single dose. The results showed that poly (DL-lactide-co-glycolide) microspheres show potential as an adjuvant for hepatitis B vaccine.     

核酸疫苗的优化方案

从抗原基因的选择、质粒载体的优化、接种方法的优化和免疫佐剂的选用等方面综述核酸疫苗的优化方案。核酸疫苗虽然在小动物实验中取得成功,但对大动物、灵长类动物和人类的免疫原性却很低。许多试图增强和调节质粒DNA疫苗的免疫原性和效率的方案都在研究之中。     

Development of Stable Influenza Vaccine Powder Formulations: Challenges and Possibilities

Influenza vaccination represents the cornerstone of influenza prevention. However, today all influenza vaccines are formulated as liquids that are unstable at ambient temperatures and have to be stored and distributed under refrigeration. In order to stabilize influenza vaccines, they can be brought into the dry state using suitable excipients, stabilizers and drying processes. The resulting stable influenza vaccine powder is independent of cold-chain facilities. This can be attractive for the integration of the vaccine logistics with general drug distribution in Western as well as developing countries. In addition, a stockpile of stable vaccine formulations of potential vaccines against pandemic viruses can provide an immediate availability and simple distribution of vaccine in a pandemic outbreak. Finally, in the development of new needle-free dosage forms, dry and stable influenza vaccine powder formulations can facilitate new or improved targeting strategies for the vaccine compound. This review represents the current status of dry stable inactivated influenza vaccine development. Attention is given to the different influenza vaccine types (i.e. whole inactivated virus, split, subunit or virosomal vaccine), the rationale and need for stabilized influenza vaccines, drying methods by which influenza vaccines can be stabilized (i.e. lyophilization, spray drying, spray-freeze drying, vacuum drying or supercritical fluid drying), the current status of dry influenza vaccine development and the challenges for ultimate market introduction of a stable and effective dry-powder influenza vaccine.     

Development of an Inhaled Sustained Release Dry Powder Formulation of Salbutamol Sulphate,an Antiasthmatic Drug

The present research was aimed to develop and characterize a sustained release dry powder inhalable formulation of salbutamol sulphate. The salbutamol sulphate microparticles were prepared by solvent evaporation method using biodegradable polymer poly (D,L-lactic-co-glycolic acid) to produce salbutamol sulphate microparticle mixed with carrier respirable grade lactose for oral inhalation of dry powder. The drug content were estimated to produce 1 mg sustained release salbutamol sulphate per dose. Total four formulations K1, K2, K3 and K4 were prepared with 1:1, 1:2, 1:3, 1:4 ratio of salbutamol sulphate:poly (D,L-lactic-co-glycolic acid). The developed formulations were studied for physicochemical properties, in vitro drug relase and Anderson cascade impaction studies. The prepared formulations effectively releases drug for 12 h in diffusion bag studies. Based on dissolution performance the 1:1 ratio of salbutamol sulphate:poly (D,L-lactic-co-glycolic acid) produces in vitro release 92.57% at 12 h and having particle size of microparticles (D_0.5μm) 5.02±0.6 and the pulmonary deposition of dry powder 34.5±3.21 (respiratory fraction in percentage).