Dry granulation and compression of spray-dried plant extracts

Suitability of botanical extracts as components of complex mixtures used in herbal tea infusions—challenges and opportunities

Herbal tea is a mainstay dosage form in practically all systems of traditional medicine and widely used in modern alternative and complementary medicine. Incorporating botanical extracts into herbal tea formulations is of vital interest to manufacturers as it allows for the use of herbal ingredients that would otherwise not be suitable for the dosage form, for instance, dosing requirements, solubility in water, sensory constraints etc. Furthermore, reducing the amount of ingredients in a formula increases compliance with dosing recommendations and thus therapeutic benefit. However, formulating with botanical extracts comes with challenges, ranging from sourcing ingredients of appropriate quality, developing suitable methods for quality control with combinations of (herbal) ingredients, processing constraints such as hygroscopicity, solubility, dispersibility, homogeneity of distribution, and packaging machinability, all the way to stability required for hot-water infusion. We report on experiences with overcoming such challenges in a set of examples and provide guidance to the extract industry on how to tap into the bagged tea sector with better suited or tailor-made solutions for the formulator.

Clinical Evaluation of a Novel Tablet Formulation of Traditional Thai Polyherbal Medicine Named Nawametho in Comparison with Its Decoction in the Treatment of Hyperlipidemia

In the traditional medical system in Thailand, medicinal plants and polyherbal medicines have been prescribed as lipid-lowering agents, including Nawametho decoction. This polyherbal formulation is described in the Worayokasan scripture. It consists of nine medicinal plants (Aegle marmelos (L.), Carthamus tinctorius L., Hibiscus sabdariffa Linn., Phyllanthus emblica L., Piper longum L., Piper nigrum L., Terminalia bellirica (Gaertn.) Roxb., Terminalia chebula Retz., and Zingiber officinale Roscoe). Apart from its utilization in Thai traditional medicine, there is a lack of evidence supporting its use. This research work thereby aims to formulate and evaluate the tablet containing Nawametho decoction. The feasibility of Nawametho decoction and NawaTab for patients with borderline hyperlipidemia was additionally examined using a prospective, open-label, randomized, parallel-group design. The dry granulation technique was employed to formulate the polyherbal tablets. The tablets were developed using the spray-dried Nawametho decoction as the active ingredient in addition to other excipients. The chosen formulation, the F_B (NawaTab), consisted of 385 milligrams of the extract, 12% w/w of a diluent (lactose), 8% w/w of a lubricant (magnesium stearate), 5% w/w of a disintegrant (microcrystalline cellulose), and 5% w/w of an anti-adherent (talcum). Their hardness, friability, and disintegration time were 4.4 ± 0.32 kg, 0.05 ± 0.02%, and 4.60 ± 0.05 min, respectively. Accelerated stability study results revealed that NawaTab was stable for six months at 40°C/75% RH and 25°C/60% RH. Even though taking NawaTabs (500 mg twice daily) for eight consecutive weeks was unable to improve the lipid profile of the patients, the administration of Nawametho decoction (30 mL twice daily) was associated with a significant decrease in serum triglycerides of the patients. The results show that the dry granulation technique is suitable for the formulation of NawaTab based on the tablet evaluation. Furthermore, the triglyceride-lowering effect of Nawametho decoction was reported for the first time.

A metabolomics approach to evaluate the effect of lyophilization versus oven drying on the chemical composition of plant extracts

Lyophilization is the “gold standard” for drying plant extracts, which is important in preserving their quality and extending their shelf-life. Compared to other methods of drying plant extracts, lyophilization is costlier due to equipment, material and operational expenses. An alternative method is post-extraction oven-drying, but the effects of this process on extract quality are unknown. In this study, crude extracts from Arthrocnemum macrostachyum shoots were compared using three post-extraction drying methods (lyophilization and oven drying at 40 and 60 °C) and two extraction solvents (water and aqueous 50% ethanol). Untargeted metabolomics coupled with chemometrics analysis revealed that post extraction oven-drying resulted in the loss of up to 27% of molecular features when compared to lyophilization in water extracts only. In contrast, only 3% of molecular features were lost in aqueous 50% ethanol extracts when subjected to oven drying. That is to say, ethanol used as a solvent has a stabilizing effect on metabolites and enhances their resistance to thermal transformation in the oven. Collectively, oven-drying of extracts was as effective as lyophilization in preserving metabolites in extracts only when 50% ethanol was used as a solvent. The results presented in this paper demonstrate the value of selecting solvent-appropriate post-extraction drying methods.

QbD approach to downstream processing of spray-dried amorphous solid dispersions - a case study

In the current study, we demonstrate a structured approach to downstream process development for spray dried amorphous solid dispersions. Direct compression is generally not suitable due to typically poor flow of spray dried powders in tablets. Roller compaction (RC) is therefore the method of choice to enable spray dried dispersion downstream processing. Here, a structured experimental design of RC process parameters was used. The objective was to identify process conditions that lead to improved powder flow without compromising tablet robustness. Ten blends were compacted using different process parameters, and subsequently compressed into tablets. The impact of process parameters on granules and tablet properties was analyzed. We demonstrate that compaction force, gap and mesh aperture have major impact on RC outcomes. A combination of large gap and low force was identified as optimum combination of RC process parameters leading to powder flow improvement that could guarantee low tablet weight variation and at the same prevented loss of blend compressibility.

Enhancement of Aqueous Solubility and Dissolution of Celecoxib through Phosphatidylcholine-Based Dispersion Systems Solidified with Adsorbent Carriers

This study aimed to design phosphatidylcholine (PC)-based solid dispersion (SD) systems for enhancing the apparent aqueous solubility and dissolution of celecoxib (CLC), a selective cyclooxygenase-2 inhibitor with a highly hydrophobic property. Although PC-based dispersion formulations considerably increased solubilities of CLC, the lipidic texture of PC was not appropriate as a solid dosage form for oral administration of CLC. To mask the lipidic texture of PC-based matrices, Neusilin^® US2, an adsorbent material with a porous structure and large surface area widely used in the pharmaceutical industry, was employed and thereby fully powderized PC-based dispersion formulations could be fabricated. However, PC matrices containing CLC strongly adsorbed to the pores of Neusilin^® US2 was not able to be rapidly released. To address this problem, different hydrophilic materials were examined to promote the release of the CLC-dispersed PC matrices from Neusilin^® US2. Among tested hydrophilic materials, croscarmellose sodium was the most suitable to facilitate fast drug dissolution from Neusilin^® US2 particles, showing significantly enhanced apparent aqueous solubility and dissolution behavior of CLC. Through differential scanning calorimetry, X-ray diffraction, and Fourier transform infrared spectroscopy (FT-IR) analysis, a considerably reduced crystallinity of CLC dispersed in the PC-based dispersion formulations was demonstrated. The PC-based SD formulations developed in this study would be useful for improving the oral bioavailability of poorly soluble drugs such as CLC.

A Review on Influence of Spray Drying Process Parameters on the Production of Medicinal Plant Powders

Medicinal plants are used by 80% of the world population as primary health care and the phytomedicine market is growing exponentially. Currently, the production of phytopharmaceuticals with proper efficacy, safety and consistent quality constitutes a relevant challenge. The dried dosage forms of medicinal plants are preferred than liquid presentations because of their higher stability. The spray drying technology is the most employed process to produce dried extracts from medicinal plant liquid extracts. These powders need to meet certain physicochemical (e.g., moisture content, hygroscopicity, particle size, density, the concentration of active ingredients) and mechanical (e.g., flowability and compressibility) properties to be used in a solid pharmaceutical form. In addition, high process yields and good powder quality can be obtained by selecting suitable process parameters: spray drying operating conditions and type/concentration of carriers (drying coadjuvants). The optimal process parameters are strongly affected by the chemical nature of the medicinal plant extract. This review aims to give a general guide to understand the effect of the process parameters on the product properties and process yield. This guideline could help practitioners and researchers to initially select the levels of the process variables to decrease the time and cost of the development stage of medicinal plants powders.

Implementation of quality by design approach in manufacturing process optimization of dry granulated, immediate release, coated tablets - a case study

The aim of this study was to optimize the process of tablets compression and identification of film-coating critical process parameters (CPPs) affecting critical quality attributes (CQAs) using quality by design (QbD) approach. Design of experiment (DOE) and regression methods were employed to investigate hardness, disintegration time, and thickness of uncoated tablets depending on slugging and tableting compression force (CPPs). Plackett-Burman experimental design was applied to identify critical coating process parameters among selected ones that is: drying and preheating time, atomization air pressure, spray rate, air volume, inlet air temperature, and drum pressure that may influence the hardness and disintegration time of coated tablets. As a result of the research, design space was established to facilitate an in-depth understanding of existing relationship between CPPs and CQAs of intermediate product (uncoated tablets). Screening revealed that spray rate and inlet air temperature are two most important factors that affect the hardness of coated tablets. Simultaneously, none of the tested coating factors have influence on disintegration time. The observation was confirmed by conducting film coating of pilot size batches.

Formulation and profile of pharmaceutical availability from a model oral solid form of a drug of phytochemicals contained in dry Taraxacum officinale extract

Introduction: Dandelion (Taraxacum officinale coll.), also called the common dandelion grows wild throughout Europe, Asia and the Americas. It is a perennial plant of the family of Asteraceae, having powerful healing properties. The entire plant – flowers, roots and leaves – is the medicinal raw material.

Objective: The aim of this study was to manufacture model tablets of pharmacopoeial disintegration time by direct compression of dry titrated extract of dandelion with selected excipients.

Methods: Tablets were obtained by direct compression using reciprocating tableting machine (Erweka). Morphological parameters – hardness, friability, disintegration time in pharmacopoeial acceptor fluids were investigated using Erweka equipment. Their actual surface area was also calculated. There was also tested the rate of dissolution of phytochemicals from model tablets in the presence of excipients in pharmacopoeial acceptor fluids (V=1.0 dm3) by the method of a basket in Erweka apparatus. Spectrophotometric determinations were performed.

Results: It results from the morphological studies of model tablets containing Ext. Taraxaci e radix cum herba aqu. siccum that they are characterized by comparable surface and friability at varying hardness, the latter depending on the applied excipients. This is reflected in the effective disintegration time in model acceptor fluids consistent with pharmacopoeial requirements.

Conclusions: The used excipients enabled to produce model tablets containing dry extract of dandelion by direct compression. The obtained results demonstrated that microcrystalline Prosolv-type cellulose, Vivapur 200 and Emdex were compatible with the structure of the extract of dandelion. They allow to manufacture a model solid oral dosage forms of the desired morphological parameters and effective disintegration time complying with the pharmacopoeial requirements.

Preparation and Evaluation of Andrographolide Solid Dispersion Vectored by Silicon Dioxide

Background:

Andrographolide (Andro) is a “natural antibiotic” as well as a typical insoluble drug. The purpose of this study was to investigate the feasibility of commercially available silica (SiO₂) as a carrier of solid dispersion to enhance the dissolution of Andro.

Materials and Methods:

The solvent evaporation method was adopted, and a series of process parameters were studied to prepare a solid dispersion. Andro, SiO₂, physical mixture, and solid dispersion were characterized with respect to particle size distribution, special surface area, pore volume, and scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction studies.

Results:

Single factor test suggested the best preparation of solid dispersion was the drug and carrier (SiO₂B) ratio of 1:8, with tetrahydrofuran as the solvent, and a recovery temperature of 50°C. Compared to crude drug and mixture, solid dispersion was found to form a unique structure to disperse the drug and displayed superior performance in rapid dissolution.

Conclusion:

The present study signifies the commercially available SiO₂ is an excellent but cheap carrier to improve the dissolution of Andro. Our results provide a highly operability approach for improving the dissolution of insoluble natural products and are beneficial for the clinical effects improvement.

SUMMARY

The potential of commercially available silica as a carrier for enhancing the insoluble drug dissolution was investigated

Factors affecting the dissolution of solid dispersion were investigated

Solid dispersion formed a unique structure to disperse the drug and release drug rapidly

Commercially available silica is an excellent but cheap carrier to improve the dissolution of Andro.

Abbreviation used: Andro: Andrographolide, BCS: Biopharmaceutics Classification System, SDS: Tetrahydrofuran and Sodium dodecyl sulfate, HPLC: High Performance Liquid Chromatography, SEM: Scanning Electron Microscope, BET: Brumauer–Emmett–Teller, FTIR: Fourier Transform Infrared Spectroscopy, XRD: X-ray Diffraction.

Retention of polyphenolic species in spray-dried blackberry extract using mannitol as a thermoprotectant

The purpose of these studies was to determine if a Büchi Mini Spray Dryer B-290 (Büchi Corporation, New Castle, DE, USA) could be used to prepare blackberry extract powders containing mannitol as a thermoprotectant without extensively degrading anthocyanins and polyphenols in the resulting powders. Three blackberry puree extract samples were each prepared by sonication of puree in 30/70% ethanol/water containing 0.003% HCl. Blackberry puree extract sample 1 (S1) contained no mannitol, while blackberry puree extract sample 2 (S2) contained 3.0:1 (w/w) mannitol:berry extract, and blackberry puree extract sample 3 (S3) contained 6.3:1 (w/w) mannitol:berry extract. The levels of anthocyanins and polyphenols in reconstituted spray-dried powders produced from S1-S3 were compared to solutions of S1-S3 that were held at 4°C as controls. All extract samples could be spray-dried using the Büchi Mini Spray Dryer B-290. S1, with no mannitol, showed a 30.8% decrease in anthocyanins and a 24.1% decrease in polyphenols following spray-drying. However, S2 had a reduction in anthocyanins of only 13.8%, while polyphenols were reduced by only 6.1%. S3, with a ratio of mannitol to berry extract of 6.3:1, exhibited a 12.5% decrease in anthocyanins while the decrease in polyphenols after spray-drying was not statistically significant (P=.16). Collectively, these data indicate that a Büchi Mini Spray Dryer B-290 is a suitable platform for producing stable berry extract powders, and that mannitol is a suitable thermoprotectant that facilitates retention of thermosensitive polyphenolic species in berry extracts during spray-drying.

Study of compressibility properties of yogurt powder in order to prepare a complementary formulation

The aim of the present study was to prepare an oral tablet from liquid yogurt by reforming the physical properties for easy transportation, long-term storage and also as a complementary dairy product in case of nutrient deficiency. The liquid fresh yogurt was lyophilized at -40°C and 0.03 mTor pressure. The dry powder was homogenized by a 12 mesh size sieve. Some tests such as Carr's compressibility index, Hausner ratio and the angle of repose were applied to evaluate the flowability of yogurt powder. Study of the deformation of particles during forcing was done by calculation of the elastic recovery index. Carr's compressibility index percent and Hausner ratio were calculated 15 and 0.94, respectively. The range of repose angle was measured between19-20°. The elastic recovery was obtained up to 60%. Since the hardness of tablets increased by decreasing compression velocity, therefore yogurt powder might have a plastic deformation. The reduction of powder volume due to compression force was about 20% (p < 0.05). Tablets with low fat yogurt showed very good compressibility with 6-12 Strong-Cab (SC) hardness units. Producing a complementary formulated as a tablet from yogurt powder is possible and also maybe therapeutically effective against lactose-intolerance syndrome and preventing antibiotic-associated diarrhea.We suggest that for more authentic confirmation of the type of deformation, it should go through Heckel's equation analysis, too.

Valeriana officinalis Dry Plant Extract for Direct Compression: Preparation and Characterization

Valeriana officinalis L. (Valerianaceae) is one of the most widely used plants for the treatment of anxiety and insomnia. Usually dry plant extracts, including V. officinalis, are hygroscopic materials with poor physico-mechanical properties that can be directly compressed.A V. officinalis dry extract with moderate hygroscocity is suitable for direct compression, and was obtained by using a simple and economical technique. The V. officinalis fluid extract was oven-dried with colloidal silicon dioxide as a drying adjuvant. The addition of colloidal silicon dioxide resulted in a dry plant extract with good physico-mechanical properties for direct compression and lower hygroscopicity than the dry extract without the carrier. The dry plant extract glass transition temperature was considerably above room temperature (about 72 °C). The colloidal silicon dioxide also produced an antiplasticizing effect, improving the powder's physical stability.The pharmaceutical performance of the prepared V. officinalis dry extract was studied through the design of tablets. The manufactured tablets showed good compactability, friability, hardness, and disintegration time. Those containing a disintegrant (Avicel PH 101) exhibited the best pharmaceutical performance, having the lowest disintegration time of around 40 seconds.

Development of granules from Phyllanthus niruri spray-dried extract

The aim of this study was to develop granules from Phyllanthus niruri spray-dried extract using dry and wet granulation and to assess techniques to enable the production of granules with improved technological characteristics and yields. Granules were characterized by granulometry, reological parameters, compression and hygroscopic behavior. Independent of the granulation technique, technologically developed granules presented particle diameter, bulk and tapped densities and compressibility indexes suitable for a solid dosage form. The compression behavior showed plastic and fragmentary deformation for granules produced by the dry granulation technique and predominantly plastic deformation for wet granulation. Concerning the humidity sorption, the study showed that granules absorb less humidity than the spray-dried extract. However, granules with Eudragit® E 100 were the least hygroscopic.

Compressional behavior of a mixture of granules containing high load of Phyllanthus niruri spray-dried extract and granules of adjuvants: comparison between eccentric and rotary tablet machines

The purpose of this paper was to evaluate the compressional behavior of granules containing high load of a Phyllanthus niruri spray-dried extract in eccentric (ETM) and rotary (RTM) tablet presses. Tablets were constituted by spray-dried extract granules (SDEG, 92%), excipient granules (EXCG, 7.92%), and magnesium stearate (0.08%). SDEG was obtained by dry granulation and EXCG, composed of microcrystalline cellulose (62.9%) and sodium starch glycolate (37.1%), by wet granulation. Particle size distribution was fixed between 0.250 and 0.850 mm. Tablets did not evidence any mechanical failures, such as lamination or capping, or anomalous weight variation in either tablet machine types. Upper and lower tablet surface photomicrographs from ETM and RTM tablets showed differences in porosity and texture. Different RTM speeds suggested the visco-plastic behavior of the formulation, since, by slowing down rotation speeds, the tensile strength of the tablets increased significantly, but the porosity and disintegration time were not affected. Tablets produced in RTM showed lower friability and porosity than ETM tablets, which did not reflect on higher tensile strength. The EXCG distribution at upper and lower surfaces from ETM and RTM tablets was quantified by image analysis and evaluated through statistical methods. Spray-dried extract release was not influenced by the type of equipment or operational conditions to which the compacts were submitted. Construction and operation differences between both tablet presses influenced the final product, since tablets with similar tensile strength, made by distinct tablet machines, exhibited different quality parameters.

Eudragit E as excipient for production of granules and tablets from Phyllanthus niruri L spray-dried extract

The aim of this study was to investigate the feasibility of using Eudragit E as a granulating agent for a spray-dried extract from Phyllanthus niruri to obtain tablets containing a high dose of this product. The granules were developed by wet granulation and contained 2.5%, 5.0%, and 10.0% Eudragit E in the final product concentration. The tablets were produced on a single-punch tablet press by direct compression of granules using 0.5% magnesium stearate as a lubricant. The tablets were elaborated following a 2 x 3 factorial design, where Eudragit E concentration and compression force were the independent variables, and tensile strength and the extract release of the tablets were the dependent variables. All granules showed better technological properties than the spray-dried extract, including less moisture sorption. The characteristics of the granules were directly dependent on the proportion of Eudragit E in the formulation. In general, all tablets showed high mechanical resistance with less than 1% friability, less moisture sorption, and a slower extract release profile. The Eudragit E concentration and compression force of the tablets significantly influenced both dependent variables studied. In conclusion, Eudragit E was efficient as a granulating agent for the spray-dried extract, but additional studies are needed to further optimize the formulations in order to achieve less water sorption and improve the release of the extract from the tablets.