Drug delivery applications and future prospects of microbial exopolysaccharides.

Over the years, exopolysaccharides (EPSs) have been utilized in various areas of research, including health, industry, environment, and agriculture, due to their flexible physical, chemical and structural properties that can be readily modified to suit desired purposes. Current research trends have shown that EPS production is dependent on numerous factors which can be combined to varying extent to optimize production yields. Although the majority of research is directed towards their industrial and medicinal uses, these chemical substances possess peculiar characteristics which are also exploited for biomedical research, where they are being used as drug delivery systems, some of which include their abundance in nature, biocompatibility, biodegradability, non-toxicity, and ability to efficiently encapsulate sensitive bioactive agents. However, despite the numerous beneficial prospects of microbial EPSs in drug delivery, there are limitations to the commercial production and industrial applications of these biopolymers. These limitations have inspired revolutionary research into the cost-effective production of safe EPSs polymers. In this review, we classify EPSs and discuss their methods of extraction and characterization. We also summarized current drug delivery applications and discussed limitations to extensive industrial commercialization of EPSs, while highlighting prospects for the utilization of microbial EPSs and implications for research.

Microsphere formulations of ambroxol hydrochloride: influence of Okra (Abelmoschus esculentus) mucilage as a sustained release polymer.

Ambroxol hydrochloride (AH), a secretion-releasing expectorant, is a good candidate for sustained delivery. Mucilages are biodegradable, inexpensive carriers in microsphere formulations. The study aimed to prepare microspheres of AH using Okra mucilage obtained from pods of Abelmoschus esculentus combined with sodium alginate at various polymer/drug ratios. Okra mucilage was characterized for morphology, swelling, viscosity and flow properties. AH microspheres were prepared by ionic emulsification method and characterized using size, entrapment efficiency, swelling index and dissolution time (t50). A full 2 by 3 factorial experimental design using three factors (Okra mucilage/alginate ratio X1; drug/polymer ratio X2; and polymer concentration X3), each at two levels, was used to determine the effects of formulation variables on the responses. Optimized formulations of AH microspheres had sizes ranging from 250.91 ± 16.22 to 462.10 ± 23.85 µm; swelling index 1.35 ± 0.05 and 3.20 ± 0.03 and entrapment 55.70 ± 3.55-94.11 ± 4.50%. The microspheres exhibited sustained release of AH over a prolonged period as revealed by the dissolution time (t50) 2.85 ± 1.03-7.50 ± 0.96 h. Drug release kinetics generally followed zero order, implying that the process is constant and independent of the initial concentration of drug. Polymer concentration had the highest influence on microsphere size, entrapment efficiency and dissolution time while Okra/alginate ratio had the highest influence on swelling. Okra mucilage was a suitable polymer that could serve as an alternative to synthetic polymers in sustaining the release of ambroxol hydrochloride.

Evaluation of mucoadhesive property and the effect of Boswellia carteri gum on intranasal vaccination against small ruminant morbillivirus infection (PPR).

A study was conducted to evaluate mucoadhesive property and immunomodulatory effect of phytogenic gums from Boswellia frereana, Boswellia carteri andCommiphora myrrha on intranasal Peste des petits ruminants (PPR) vaccination in goats and sheep in an ex-vivo and in-vivo situations. Plant gums were purified, dried and compressed into 500gm tablets. Modified shear stress measurement technique was used on freshly excised trachea and intestine tissues of goat to measure peak adhesion time. Forty eight animals (24 goats and 24 sheep) were divided into eight groups (of 3 goats and 3 sheep) and immunized intranasally with gum-vaccine combinations in two ratios (1:1, 1:2). Antibody against PPR virus was measured on day 14, 28, 42 and 56 post vaccination using H-based PPR bELISA. The peak adhesion time of the different gums was transient. PPR virus antibodies were detected in all immunized goats and sheep but not in unvaccinated control. The best percentage inhibition was recorded for Boswellia carteri-vaccine combination group at a ratio of 1:1. Administration of Boswellia carteri-PPR vaccine combination through intranasal or subcutaneous route, elicited similar antibody titre, implying that the intranasal route may be used as a non-invasive alternative delivery in PPR vaccination of small ruminants.

Starch nanoparticles in drug delivery: A review.

The uptake and specificity of drugs and the bioavailability of poorly soluble drugs has been improved by means of targeted drug delivery using nanoparticles. Many platforms have been used for nanoparticulate drug delivery and these include liposomes, polymer conjugates, metallic nanoparticles, polymeric micelles, dendrimers, nanoshells, and protein and nucleic acid-based nanoparticles. Starch is the 2nd most abundant natural polymer and has found wide use in drug delivery systems as binder, disintegrant and filler. However, its application is limited by the poor functional properties of native starch. Starch nanocrystals of different shapes and sizes can be obtained based on the starch origin and isolation process involved. Nanocrystals with varying morphology have been reported; from nanocrystals of platelet-like shaped waxy maize starch with 5-7 nm thickness and 15-40 nm diameters, to those with round and grape-like shape from potato starch granules, with sizes ranging from 40 nm to 100 nm. This review describes different methods of obtaining starch nanoparticles, their modification and application in drug delivery.

Evaluation of two novel plant gums for bioadhesive microsphere and sustained-release formulations of metformin hydrochloride.

BACKGROUND: The biological half life of metformin requires multiple doses which are associated with poor patient compliance. This justifies the need for a dosage form with reduced dosing frequency. OBJECTIVES: Gums from Enterolobium cyclocarpum and Cedrela odorata trees were evaluated in formulating bioadhesive microspheres containing metformin hydrochloride, for sustained drug release. Hydroxylpropylmethyl cellulose (HPMC) was the standard. MATERIAL AND METHODS: Microspheres were produced from formulations of API and either cedrela gum (FC), enterolobium gum (FE) or HPMC (FH), using a W/O solvent extraction technique. The microspheres were characterized using a particle size analyzer, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), powder X-ray diffractometer (PXRD), drug entrapment, in vitro release and mucoadhesion studies. The data was analyzed using ANOVA and t-test at p = 0.05. RESULTS: FT-IR spectroscopy indicated no alteration in the functional groups of metformin. A yield of 92-98% microspheres was obtained from all the formulations which had a particle size range of 72-84 µm. SEM revealed cylindrical to near-spherical particles with rough surfaces. The drug release profile showed a burst over the first 30 min followed by a steady release for about 5 h and a slow release for 5 days. Formulations containing the gums sustained the release of API for almost the same time as HPMC formulations; the ranking order was FE > FH > FC (p > 0.05). All the formulations exhibited good concentration-dependent mucoadhesive properties. CONCLUSIONS: The gums were suitable for formulation of mucoadhesive microspheres for sustained release of metformin. The formulations showed good release properties in an alkaline pH.

Native and microwave-modified Terminalia mantaly gums as sustained-release and bioadhesive excipients in naproxen matrix tablet formulations.

BACKGROUND: Hydrophilic polymers provide a means of sustaining drug delivery. Native gums may be limited in function, but modification may improve their activity. OBJECTIVES: The aim of the study was to evaluate native and modified forms of Terminalia mantaly gum for their sustained-release and bioadhesive properties. MATERIAL AND METHODS: The native gum (NTM) was modified by microwave irradiation for 20 seconds (MTM20) and 60 seconds (MTM60) and characterized using microscopy, Fourier transform infrared spectroscopy (FTIR) and packing properties. The effects of the thermally induced molecular reorientation were determined. Tablet formulations of naproxen were produced by direct compression. The mechanical, bioadhesive and release properties of the formulations were determined. RESULTS: Irradiation of NTM improved the gum's flow properties, resulting in Carr's Index and Hausner's ratios lower than 16% and 1.25, respectively. Swelling studies showed that MTM20 and MTM60 had lower water absorption capacity and swelling index values, while packing properties improved upon irradiation, as depicted by lower tapped density values. FTIR spectra of samples showed that the irradiated gums were distinct from the native gums and did not interact with naproxen sodium. The gum's mechanical properties improved with MTM20 and MTM60 and sustained-release action of up 12 h was obtained. CONCLUSIONS: Inclusion of hydroxypropyl methylcellulose (HPMC) in the tablet formulations proved critical for bioadhesion. Microwave irradiation of native Terminalia mantaly gum improved the flow, mechanical and sustained-release properties of Naproxen tablets, and the addition of HPMC increased bioadhesion properties. The tablet properties of the native gum were significantly improved after 20 s of microwave irradiation.

Formulation and Evaluation of Oral Dissolving Films of Amlodipine Besylate Using Blends of Starches With Hydroxypropyl Methyl Cellulose.

BACKGROUND: Natural polymers serve as cheap, non-toxic, biocompatible excipients in oral drug delivery. These advantages inform their uses in the design of drug dosage forms. OBJECTIVES: The aim of the study was to prepare and evaluate oral dissolving films of amlodipine besylate, an anti-hypertensive drug, using starch/polymer blends. MATERIAL AND METHODS: Bambara nut (BAM) and the African yam bean (AYB) starches were individually blended with hydroxypropyl methyl cellulose (HPMC). The material and rheological properties of the blends were determined. Amlodipine besylate was incorporated by dispersion and films were prepared by solvent evaporation method and evaluated for mechanical and drug release properties. RESULTS: The BAM/HPMC blends had higher viscosity values than the corresponding AYB/HPMC blends. All the blends gave a Hausner ratio above 1.25 and Carr's index above 22. Blends of ratio 1 : 1 and 2 : 1 produced good films and were subsequently evaluated. All films disintegrated within 15 mins but had poor folding endurance. BAM/HPMC (1 : 1) and AYB/ /HPMC (2 : 1) released all of the drug content within 30 min. The ranking for dissolution profile was AYB/HPMC (2 :1 ) > BAM/ /HPMC (1 :1 ) > BAM/HPMC (2 : 1) > AYB/HPMC (1 : 1). The type and ratio of starch in the blend influenced the drug release pattern of the films. CONCLUSIONS: Starch/HPMC blend ratios of 1 : 1 and 2 : 1 were found suitable for the formulation of oral dissolving film of amlodipine besylate with good disintegration time and drug release profile.

Material and Compression Properties of Cedrela odorata Gum Co-Processed with Plantain Starch and Microcrystalline Cellulose.

BACKGROUND: Many excipients used in tableting exhibit some undesirable properties such as poor flow, cohesion and lubricating characteristics, thus necessitating some modification to achieve the desired product. OBJECTIVES: The objective of this study was to enhance the material, flow and compressional properties of Cedrela odorata gum (COG) (Family: Meliaceae) by co-processing with plantain starch (PS) and microcrystalline cellulose (MCC). MATERIAL AND METHODS: The COG was co-processed with PS (or MCC) by physical co-grinding at ratio 1 : 1, 1 : 2 and 1 : 4, and characterized using morphological analysis, swelling index viscosity measurements, particle size analysis and FTIR spectra. The material, flow and compressional properties of the co-processed excipients were also evaluated. Results were analyzed using mean and standard deviation of data. RESULTS: There was a decrease in the degree of agglomeration of COG and a reduction in the size of the powdered gum. The co-processed excipients were more spherical than the native excipients. The COG had the highest viscosity, while MCC and COG : PS (1 : 2) showed the highest and lowest degrees of swelling at 27.0 ± 0.05°C respectively. Water absorption capacity of the component excipients improved with co-processing COG : MCC increasing from 171.8 ± 1.54 (1 : 1) to 214.8 ± 1.07 (1 : 2), while COG : PS increased from 95.2 ± 0.08 (1 : 1) to 206.2 ± 0.13. There was a decrease in the percentage solubility of the co-processed excipients with the highest and lowest solubility observed in COG (54.1 ± 0.07%) and PS (3.7 ± 0.16%), respectively. The FTIR spectra indicate no significant interaction between the excipients. The poor flow of the component excipients did not improve with co-processing; however, there was a significant increase in compressibility. Generally, COG co-processed with MCC showed better compression properties when compared with COG co-processed with PS. CONCLUSIONS: Co-processing of COD with MC or PS enhanced the characters of the component excipients, thus making the co-processed excipients suitable for direct compression of tablets without altering the chemical nature of the component excipients.

Application of freeze-drying technology in manufacturing orally disintegrating films.

Freeze drying technology has not been maximized and reported in manufacturing orally disintegrating films. The aim of this study was to explore the freeze drying technology in the formulation of sildenafil orally disintegrating films and compare the physical properties with heat-dried orally disintegrating film. Central composite design was used to investigate the effects of three factors, namely concentration of carbopol, wheat starch and polyethylene glycol 400 on the tensile strength and disintegration time of the film. Heat-dried films had higher tensile strength than films prepared using freeze-dried method. For folding endurance, freeze-dried films showed improved endurance than heat-dried films. Moreover, films prepared using freeze-dried methods were thicker and had faster disintegration time. Formulations with higher amount of carbopol and starch showed higher tensile strength and thickness whereas formulations with higher PEG 400 content showed better flexibility. Scanning electron microscopy showed that the freeze-dried films had more porous structure compared to the heat-dried film as a result of the release of water molecule from the frozen structure when it was subjected to freeze drying process. The sildenafil film was palatable. The dissolution profiles of freeze-dried and heat-dried films were similar to Viagra® with f2 of 51.04 and 65.98, respectively.

Effects of modification and incorporation techniques on disintegrant properties of wheat (Triticum aestivum) starch in metronidazole tablet formulations.

BACKGROUND: Natural polymers serve as cheap, non-toxic, biocompatible excipients in drug delivery. OBJECTIVES: Starch from wheat (Triticum aestivum) was investigated as a disintegrant in metronidazole tablet formulations in comparison with sodium starch glycolate (SSG), a standard, synthetic but relatively more expensive disintegrant. MATERIAL AND METHODS: Native wheat starch (NAS) was modified by pregelatinization (PGS) and microwave irradiation (MCW). The starches were characterized using swelling capacity, angle of repose, density measurements, Carr's index and Hausner's ratio. Metronidazole tablet formulations were made with the starches incorporated by intragranular (IG), extra-granular (EG) or intra/extragranular (IG/EG) methods. Tablet properties of crushing strength, disintegration time and dissolution tests were determined. RESULTS: Native wheat starch had better hydration capacity than the modified starches, with PGS having a higher swelling capacity than the MCW. Modified starches formed better compacts than both NAS and SSG as indicated by the higher crushing strength of tablets containing modified starches. Intragranular incorporation gave a higher crushing strength than both EG and IG/EG methods. The ranking for disintegration time of tablets was IG/EG > IG > EG among the incorporation methods and SSG > PGS > MCW > NAS among the starches (EG > IG/EG). The difference between IG/EG and EG was significant (p < 0.05) but not significant between IG and other incorporation methods (MCW > SSG > PGS). Native and modified wheat starches exhibited better disintegrant properties than sodium starch glycolate in metronidazole tablet formulations. CONCLUSIONS: The mode of disintegrant incorporation and modification of wheat starch had different effects on tablet properties of metronidazole formulations. The modification technique and method of disintegrant incorporation should be determined based on desired tablet properties.

The effect of processing variables on the mechanical and release properties of tramadol matrix tablets incorporating Cissus populnea gum as controlled release excipient.

BACKGROUND: Natural gums are polymers widely used as excipients in drug formulation. Polymer extraction and formulation processing methods could significantly affect formulation characteristics. OBJECTIVES: To evaluate different methods of gum extraction and the effect of different compression methods on the mechanical and release properties of tramadol hydrochloride matrix tablets incorporating cissus gum as controlled release polymer. MATERIAL AND METHODS: Water (CW) and acetone (CA) extracts of cissus gum were obtained from Cissus populea stem and two methods - wet granulation and direct compression - were used to compress the tablet and compare it with xanthan gum (X) formulations. Crushing strength and friability were used to assess mechanical properties while dissolution rate were used to assess release properties. Data were analysed using t-test and ANOVA at p < 0.05. RESULTS: The crushing strength of tramadol tablets has increased together with the increase in polymer concentration in all formulations, while friability has decreased for both methods. Tablets made by wet granulation had higher crushing strength than those made by direct compression method. The release mechanism for both direct compression and wet granulation methods was Fickian and non-Fickian respectively. The rank order for t25, t50 and t75 for all formulations was X > CA > CW. Generally, wet granulation method decreased the rate of tramadol release more than direct compression method, indicating a higher drug retarding ability. CONCLUSIONS: Incorporation of cissus gum controlled the release of tramadol hydrochloride from the matrix tablets. Extraction method and formulation variables influenced mechanical and release properties of the tablets. Cissus gum acetone extract had comparable release properties with xanthan gum and could serve as a cheaper alternative in controlled release tablet formulations.

Effects of excipients and formulation types on compressional properties of diclofenac.

Different models used to characterize powders have not been extended to granule behavior in tablet technology. Hence, Kawakaita equation and tapping experiments were used to compare the effect of different excipients on the properties of powders and granules in diclofenac formulations containing corn starch (DCS), lactose (DL) and dicalcium phosphate (DDCP). The binding properties of Albizia gum from Albizia zygia tree were also compared with those of gelatin in the granule formulations. Diclofenac (powder and granule) formulations were characterized for particle size and particle size distribution. Volume reduction was done by subjecting materials to N number of taps. Values of maximum volume reduction (a 'determined') and index of compressibility (b) were obtained from the plots of N/C against powder volume reduction with tapping (C). Another value for a (a' calculated) were obtained from Kawakita equations. The individual and interaction effects of type of diluent (X1) and formulation (X2) on the characteristics of powder and granule were determined, using a 22 factorial experimental design. The mean granule size increased with binder concentration, larger granules were obtained with Albizia gum than gelatin in the formulations. In DCS, a was lower in granules, granules had higher values of a than powders in DDCP (p < 0.05). There were no significant differences in the values of a' for granule and powder formulations. Diclofenac had higher compressibility index (b) with the excipients. Generally, b was higher in granules than in powder formulations (p < 0.05). The factorial analysis indicates no significant differences in the contribution of formulation type to the compression properties. Granules and powders can be characterized using the same parameters. Albizia gum was shown to confer good flow and compression properties in diclofenac formulations.

Evaluation of Cedrela gum as a binder and bioadhesive component in ibuprofen tablet formulations

The compressional, mechanical and bioadhesive properties of tablet formulations incorporating a new gum obtained from the incised trunk of the Cedrela odorata tree were evaluated and compared with those containing hydroxypropylmethylcellulose (HPMC). Compressional properties were evaluated using Hausner's ratio, Carr's Index, the angle of repose, and Heckel, Kawakita and Gurnham plots. Ibuprofen tablets were prepared using the wet granulation method. Bioadhesive studies were carried out using the rotating cylinder method in either phosphate buffer pH 6.8 or 0.1 M hydrochloric acid media. The gum is a low viscosity polymer (48 cPs), and Fourier transform infrared spectroscopy revealed the presence of a hydroxyl group. Py and Pk values, which are measures of plasticity, showed the gum to be significantly (p<0.05) more plastic than HPMC, and plasticity increased with polymer concentration. All tablet formulations were non-friable (<1.0%), and the formulations containing the gum had a higher crushing strength (130.95 N) than those containing HPMC (117.85 N) at 2.0% w/w binder. Formulations incorporating the gum were non-disintegrating and had a significantly longer drug release time than those containing HPMC. At the highest binder concentration, Cedrela gum formulations adhered to incised pig ileum longer than those containing HPMC. Cedrela gum exhibited better compressive, flow and binding properties than HPMC and is suitable as a bioadhesive and for sustained release of drugs.

Propriedades de compressão, mecânicas e de formulações de comprimidos bioadesivos, que incorporam nova goma de mascar obtidas a partir de incisão de tronco da árvore de Cedrela odorata, foram avaliadas e comparadas com aquelas contendo hidroxipropilmetilcelulose (HPMC). Propriedades de compressão foram avaliadas usando a razão de Hausner, índice de Carr, ângulo de repouso e os gráficos de Heckel, Kawakita e Gurnham. Prepararam-se comprimidos de ibuprofeno utilizando o método de granulação a úmido. Realizaram-se estudos de bioadesividade utilizando o método de cilindro rotativo em tampão fosfato pH 6,8, ou meio ácido com 0,1 M de ácido clorídrico. A goma é um polímero de baixa viscosidade (48 cPs) e a espectroscopia no infravermelho por Transformada de Fourier (FTIR) revelou a presença de um grupo hidroxila. Valores de Py e Pk, que são medidas de plasticidade, mostraram que a goma é significativamente (p <0,05) mais plástica do que HPMC e que a plasticidade aumenta com a concentração de polímero. Todas as formulações de comprimidos mostraram-se não-friáveis (<1,0%) e aquelas contendo a goma apresentaram maior resistência ao esmagamento (130.95N) do que aquelas contendo HPMC (117.85N) em 2,0% (p/p) do ligante. As formulações que incorporaram a goma eram não-desintegrantes e apesentaram tempo de liberação significativamente maior do que aquelas contendo HPMC. As formulações de goma de Cedrela aderiram à incisão de íleo de porco por tempo maior do que aquelas contendo HPMC com a maior concentração de ligante. A goma Cedrela apresentou melhor fluxo, compressão e propriedades de ligação do que HPMC e é adequada como bioadesivo e para a liberação sustentada de fármacos.

Influence of binder type and process parameters on the compression properties and microbial survival in diclofenac tablet formulations

The influence of binder type and process parameters on the compression properties and microbial survival in diclofenac tablet formulations were studied using a novel gum from Albizia zygia. Tablets were produced from diclofenac formulations containing corn starch, lactose and dicalcium phosphate. Formulations were analyzed using the Heckel and Kawakita plots. Determination of microbial viability in the formulations was done on the compressed tablets of both contaminated and uncontaminated tablets prepared from formulations. Direct compression imparted a higher plasticity on the materials than the wet granulation method. Tablets produced by wet granulation presented with a higher crushing strength than those produced by the direct compression method. Significantly higher microbial survival (p< 0.05) was obtained in formulations prepared by direct compression. The percent survival of Bacillus subtilis spores decreased with increase in binder concentration. The study showed that Albizia gum is capable of imparting higher plasticity on materials and exhibited a higher reduction of microbial contaminant in the formulations. The direct compression method produced tablets of reduced viability of microbial contaminant.

A influência do tipo de ligante e os parâmetros do processo de propriedades de compressão e sobrevivência microbiana em comprimidos de diclofenaco foram estudados utilizando uma nova goma de Albizia zygia. Os comprimidos foram produzidos a partir de formulações de diclofenaco contendo amido de milho, lactose e fosfato bicálcico. As formulações foram analisadas usando os gráficos de Heckel e Kawakita. A determinação da viabilidade microbiana nas formulações foi feita nos comprimidos contaminados e não contaminados preparados a partir de formulações. A compressão direta confere maior plasticidade dos materiais do que o método de granulação úmida. Comprimidos produzidos por granulação úmida apresentaram maior força de esmagamento do que aqueles produzidos pelo método de compressão direta. Observou-se sobrevivência significativamente maior (p<0,05) em formulações preparadas por compressão direta. A sobrevivência percentual dos esporos de Bacillus subtilis diminuiu com o aumento da concentração do agregante. O estudo mostrou que a goma de Albizia é capaz de conferir maior plasticidade aos materiais e apresentou maior redução da contaminação microbiana nas formulações. O método de compressão direta produziu comprimidos com viabilidade reduzida de contaminantes microbianos.

Powder properties of binary mixtures of chloroquine phosphate with lactose and dicalcium phosphate / Propriedades do pó de misturas binárias de fosfato de cloroquina com fosfato bicálcico e lactose

A study was conducted on the packing and cohesive properties of chloroquine phosphate in binary mixtures with lactose and dicalcium phosphate powders. The maximum volume reduction due to packing as expressed by the Kawakita constant, a, and the angle of internal flow, θ, were the assessment parameters. The individual powders were characterized for their particle size and shape using an optical microscope. Binary mixtures of various proportions of chloroquine phosphate with lactose and dicalcium phosphate powders were prepared. The bulk and tapped densities, angles of repose and internal flow, as well as compressibility index of the materials were determined using appropriate parameters. The calculated and determined values of maximum volume reduction for the binary mixtures were found to differ significantly (P< 0.05), with the Kawakita plot being more reliable in determining the packing properties. Diluent type was found to influence the flow properties of the mixtures, with dicalcium phosphate giving predictable results while mixtures containing lactose were anomalous with respect to flow. The characterization of the packing and cohesive properties of the binary mixtures of chloroquine with lactose and dicalcium phosphate would be useful in the production of powders, tablets, capsules and other drug delivery systems containing these powders with desirable and predictable flow properties.

Realizou-se estudo das propriedades de empacotamento e de coesão do fosfato de cloroquina em misturas binárias com lactose e fosfato dicálcico em pó. O volume máximo de redução devido ao empacotamento, segundo expresso pela constante de Kawakita, a, e o ângulo de fluxo interno, θ, foram os parâmetros de avaliação. Os pós individuais foram caracterizados por seu tamanho e forma de partículas, utilizando microscópio óptico. Prepararam-se misturas binárias de várias proporções de fosfato de cloroquine e lactose e fosfato dicálcico em pó. As densidades de bulk and tapped, os ângulos de repouso e de fluxo interno e o índice de compressibilidade dos materiais foram determinados utilizando-se parâmetros apropriados. Os valores calculados e determinados do volume máximo de redução para as misturas binárias mostraram-se significativamente diferentes (P< 0,05), sendo o traçado de Kawakita mais confiável na determinação das propriedades de empacotamento. O tipo de diluente influenciou as propriedades de fluxo das misturas com fosfato dicálcico, dando resultados previsíveis, enquanto as misturas contendo lactose mostraram-se anômalas com relação ao fluxo. A caracterização das propriedades de empacotamento e de coesão das misturas binárias de cloroquina com lactose e fosfato dicálcico seria útil na produção de pós, comprimidos, cápsulas e outros sistemas de liberação de fármacos contendo esses pós com propriedade de fluxo desejada e previsível.