Pharmaceutical Suspensions Research Articles

RP-HPLC Method Development and Validation For Simultaneous Estimation of Paracetamol and Mefenamic Acid in Pharmaceutical Suspension

Paracetamol (PCT) and Mefenamic acid (MFA), in combination, is recommended widely for the treatment of antipyretic and anti-inflammatory conditions. The present works carry a new simple, rapid, precise, accurate, and sensitized method of high-performance liquid chromatography with UV detection for simultaneous quantification of PCT and MFA. The samples are eluted in isocratic mode using a Phenomenex ODS 3V C18 (4.6mm × 250 mm i.d, with a particle size of 5μm) with the mobile composition of methanol: phosphate buffer pH 7.1 (70:30) delivered at a flow rate of 1ml/min with the detection wavelength of 254 nm. It shows good linearity response in the concentration range of 15-35 μg/mL and 6-14 μg/ml for PCT and MFA with the retention times of 3.0 min and 4.8 min, respectively. The quantities of PCT and MFA in pharmaceutical suspension were found to be 99.01% and 101.02%, respectively. The method was quantitatively evaluated according to ICH guidelines taking into consideration the required parameters, and the results obtained are within acceptable limits. So, the proposed method can be employed in the routine analysis and evaluation of MFA and PCT in both bulk and suspension dosage form.

Particle Surface Roughness Improves Colloidal Stability of Pressurized Pharmaceutical Suspensions.

The effects of particle size and particle surface roughness on the colloidal stability of pressurized pharmaceutical suspensions were investigated using monodisperse spray-dried particles. The colloidal stability of multiple suspensions in the propellant HFA227ea was characterized using a shadowgraphic imaging technique and quantitatively compared using an instability index. Model suspensions of monodisperse spray-dried trehalose particles of narrow distributions (GSD< 1.2) and different sizes (MMAD= 5.98μm, 10.1μm, 15.5μm) were measured first to study the dependence of colloidal stability on particle size. Particles with different surface rugosity were then designed by adding different fractions of trileucine, a shell former, and their suspension stability measured to further study the effects of surface roughness on the colloidal stability of pressurized suspensions. The colloidal stability significantly improved (p< 0.001) from the suspension with 15.5μm-particles to the suspension with 5.98μm-particles as quantified by the decreased instability index from 0.63 ± 0.04 to 0.07 ± 0.01, demonstrating a strongly size-dependent colloidal stability. No significant improvement of suspension stability (p> 0.1) was observed at low trileucine fraction at 0.4 % where particles remained relatively smooth until the surface rugosity of the particles was improved by the higher trileucine fractions at 1.0 % and 5.0 %, which was indicated by the substantially decreased instability index from 0.27 ± 0.02 for the suspensions with trehalose model particles to 0.18 ± 0.01 (p< 0.01) and 0.03 ± 0.01 (p< 0.002) respectively. Surface modification of particles by adding shell formers like trileucine to the feed solutions of spray drying was demonstrated to be a promising method of improving the colloidal stability of pharmaceutical suspensions in pressurized metered dose inhalers.

A novel technique for intraduodenal administration of drug suspensions/solutions with concurrent pH monitoring applied to ibuprofen formulations

Characterization of dissolution of solid suspended drug particles in vivo is important for developing biopredictive in vitro tests. Therefore, methods to gain deeper insights into particle dissolution in vivo are needed. The soft Bioperm intubation method, a well established tool for investigation of permeability, absorption, metabolism, and drug interactions at predefined locations in the gastroinstinal tract, was modified. The novel intubation method involved pump-controlled infusion of pharmaceutical suspensions as well as simultaneous pH monitoring. This technique was used in a proof of concept study in healthy humans. Plasma sampling and non-compartmental analysis allowed comparison of three different ibuprofen drug products, a solution and two suspensions with different particle size distribution, as well as two different infusion rates. Both a particle size effect and an effect of altering infusion rates on pharmacokinetic parameters were shown. Moreover, it was possible to monitor intestinal pH changes after intestinal infusion. Infusion of ibuprofen resulted in a pH drop that was quantified by the concept of Area Between Curves (ABC).

EXPLORING PROPERTIES OF SWEET BASIL SEED MUCILAGE IN DEVELOPMENT OF PHARMACEUTICAL SUSPENSIONS AND SURFACTANT-FREE STABLE EMULSIONS

Objective: The objective of the investigation was to isolate mucilage from sweet basil seeds and explore its physicochemical properties for the development of pharmaceutical suspensions and surfactant-free stable emulsions.Methods: Possible applications of sweet basil seed mucilage in the pharmaceutical field for dosage form development are being explored. The physicochemical and functional properties of the mucilage from the seeds of the Ocimum basilicum L. (Sweet basil) have been investigated for stabilization of suspensions and emulsions. The following analyses were performed: FTIR spectroscopy, phytochemical tests, XRD, swelling and rheological studies.Results: The analyses showed that the mucilage is rich in glucose, mannose, and xylose. High swelling index values varying from 100±10 to 200±13%, high water-holding capacity of 97.5±2.4 g/g mucilage and reasonable oil holding capacity of the mucilage (13.2±1.3 g/g mucilage) makes it an ideal candidate for utilization as viscosifier and stabilizer of suspensions and surfactant-free emulsions. Adult and paediatric paracetamol suspension formulations with 1%w/v mucilage have exhibited flocculated nature and good stability owing to its high sedimentation volume(F= 0.85-0.98) and good redispersibility. Sunflower oil emulsions prepared with 0.25%w/v mucilage demonstrated emulsion stability index of 105.714 on 5th day and extremely low creaming rate of 0.0004 cm/h thus confirming maximum stability compared to emulsions developed with 0.3-0.5% w/v mucilage.Conclusion: The mucilage isolated from Ocimum basilicum L. seeds may be regarded as a functional biomaterial for pharmaceutical use to ensure quality and stability of liquid dosage forms.

A continuous manufacturing concept for a pharmaceutical oral suspension

The aim of this study was to investigate the applicability of an innovative continuous manufacturing system for semi-solid and liquid pharmaceutical formulations. A commercially available pharmaceutical oral suspension was selected as model formulation. Premixes of the raw materials were dosed via peristaltic pumps to the mixing compartment, which consists of two consecutive mixing units. An experimental design was used to study the influence of several process parameters (throughput, mixing speed in mixing unit 1 and mixing speed in mixing unit 2) on the quality attributes of the oral suspension. The pH, density, active pharmaceutical ingredient (API) concentration, sedimentation after 30 days (expressed by the sedimentation volume) and rheological characteristic (yield stress) of the suspension were determined. No significant influence of the process parameters on the pH, density and API concentration was observed. The throughput and mixing speed in mixing unit 1 had a significant impact on both the sedimentation volume and yield stress, and were therefore critical to acquire physical stable suspensions. Furthermore, the yield stress measured one day after production was predictive for the occurrence of sedimentation in the suspensions after 30 days. When selecting the optimal process settings, the continuously manufactured suspension had a similar product quality as the original batch-processed suspension and even possessed a higher yield stress. This study demonstrated that the investigated innovative continuous manufacturing technology is suitable for the manufacturing of a commercially available pharmaceutical suspension and that the product quality can be optimized by adjusting the process parameters.

Stability Study of Etoricoxib a Selective Cyclooxygenase-2 Inhibitor by a New Single and Rapid Reversed Phase HPLC Method

Cyclooxygenase-2 (COX-2) is an enzyme responsible for inflammation and pain. Etoricoxib is the most recent selective (COX-2) inhibitor that has a higher COX-2 selectivity than the other COX-2-selective nonsteroidal anti-inflammatory drugs (NSAIDs), which significantly improves its gastric safety profile. The current therapeutic indications of etoricoxib includes the treatment of several painful conditions, such as osteoarthritis, acute gout, ankylosing spondylitis, and rheumatoid arthritis. To the best of found knowledge, no decent method has been reported that can be used for the routine determination of etoricoxib and additives in pharmaceutical suspensions by a single, rapid and cost-effective run of HPLC, using an UV-Vis detector. Earlier reported methods, such as liquid chromatography-mass spectrometry (LC-MS), high performance thin layer chromatography (HPTLC), capillary zone electrophoresis, and ultra performance liquid chromatography (UPLC), are all tedious and time consuming. A reversed phase high performance liquid chromatography (RP-HPLC) was used as a first reported single run method to achieve developed and validated simultaneous determination for sodium saccharin, vanillin, methyl paraben, etoricoxib, and butyl paraben, in prepared oral suspensions of etoricoxib. Reversed phase column of octadecylsilane (ODS) C18 with isocratic mobile phase containing methanol, and phosphate buffer of pH 6 in a ratio of 70:30 (v/v). Celecoxib is used as an internal standard at a detection wavelength of 215 nm. This method separates the analytes in a total running time less than 13 min. Linearity is obtained in the calibration curve for all analytes with a R2 value of &gt; 0.999. Furthermore, beta-cyclodextrin (β-CD) and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) were added, either alone or combined, to prevent the crystal formation, and any unpleasant taste of etoricoxib in oral formulations. After testing both HP-β-CD and β-CD at 3% w/w for each, the results showed that HP-β-CD is more efficient in preventing the crystal formation of etoricoxib in suspensions at room temperature than β-CD is.

Characterization of the suspension stability of pharmaceuticals using a shadowgraphic imaging method

A new shadowgraphic imaging method and an associated instrument for analyzing the physical stability of pharmaceutical suspensions are introduced in this paper. The new suspension tester consists mainly of a high-resolution camera that takes sequential shadowgraphic images of emulsions or suspensions and a 2D collimated LED for simultaneous whole-sample illumination in bright field. A built-in ultrasonic bath provides controlled initial agitation to the samples of interest. Sequential images acquired by the experimental setup were used to derive normalized transmission profiles from which an instability index was developed for quantitative stability comparison between samples. Instrument performance was verified by measuring the stability of a series of oil-in-water emulsions prepared with surfactant mixtures of different ratios. The new instrument correctly determined the required hydrophilic-lipophilic balance for sunflower oil to be 7.0. The stability of a pressurized suspension of spray dried lipid (DSPC) particles was monitored for 5 days after propellant filling. Although stable for the first 24 h, the lipid suspension was found to decrease in stability from day 1 to day 4. Morphological and spectroscopic analysis revealed that the suspended DSPC particles had reformed into large thin sheets of lipid, thereby causing the gradual stability decrease during the aging study. The effects of initial agitation on the stability of suspensions were demonstrated by agitating a suspension of micronized fluticasone propionate in propellant using a wrist action shaker and an ultrasonic bath respectively. A significant improvement of suspension stability was achieved by replacing the wrist action shaker method with ultrasonic agitation. Simultaneous illumination of the complete suspension, a high image acquisition rate, and controlled initial agitation are features that make this new suspension tester a suitable and more reliable instrument for investigating the stability of pressurized pharmaceutical suspensions.

Compilation of a Near-Infrared Library for Construction of Quantitative Models of Oral Dosage Forms for Amoxicillin and Potassium Clavulanate.

The accuracy of quantitative models for near-infrared (NIR) spectroscopy is dependent upon calibration samples with concentration variations. Conventional sample-collection methods have shortcomings (especially time-consumption), which creates a “bottleneck” in the application of NIR models for Process Analytical Technology (PAT) control. We undertook a study to solve the problem of sample collection for construction of NIR quantitative models. Amoxicillin and potassium clavulanate oral dosage forms (ODFs) were used as examples. The aim of this study was to find an approach to construct NIR quantitative models rapidly using a NIR spectral library based on the idea of a universal model. The NIR spectral library of amoxicillin and potassium clavulanate ODFs was defined and comprised the spectra of 377 batches of samples produced by 26 domestic pharmaceutical companies, including tablets, dispersible tablets, chewable tablets, oral suspensions, and granules. The correlation coefficient (rT) was used to indicate the similarities of the spectra. The calibration sets of samples were selected from a spectral library according to the median rT of the samples to be analyzed. The rT of the samples selected was close to the median rT. The difference in rT of these samples was 1.0–1.5%. We concluded that sample selection was not a problem when constructing NIR quantitative models using a spectral library compared with conventional methods of determining universal models. Sample spectra with a suitable concentration range in NIR models were collected rapidly. In addition, the models constructed through this method were targeted readily.

Model-based NIR spectroscopy implementation for in-line assay monitoring during a pharmaceutical suspension manufacturing process

The implementation of Process Analytical Technology (PAT) instruments is generally achieved stochastically. Sub-optimal PAT locations could introduce variation in the measurements which is not related to the analyte of interest. For this reason, rational approaches should be considered to establish an optimal sensor placement where relevant measurements are possible and the impact of disturbances is minimized. The aim of this paper is to demonstrate how mechanistic modelling can support appropriate sensor implementation by means of a case study. A PAT method was developed for a bottle filling process of a pharmaceutical formulation with the goal of increasing the yield of the process by gaining process understanding and redefining the endpoint of the process. To ensure proper measurements, an advanced measuring interfacing was assembled. The design of this device was rationalized with the help of a model-based approach using three-dimensional Computational Fluid Dynamics modeling. This allows to maximize the performance of the PAT method and exploit its full benefits.

The Taste of Commercially Available Clarithromycin Oral Pharmaceutical Suspensions in the Palestinian Market: Electronic Tongue and In Vivo Evaluation.

Background: The taste of oral liquid dosage forms is a crucial factor that impacts paediatric patient compliance. The electronic tongue (ET) is an emerging tool that could be useful in taste assessment in order to minimize the involvement of humans in such evaluations. Purpose: The aim of this study is to evaluate the taste of commercially available clarithromycin (CM) oral pharmaceutical suspensions in the Palestinian market. Method: Commercially available CM suspensions (the brand Klacid® and two generic K1 and K2) were assayed using the high performance liquid chromatography (HPLC) method. Then, the taste of these products was assessed using alpha-astree ET. In addition, an in vivo taste assessment was conducted on paediatric patients by a hedonic panel test. Moreover, volunteering community pharmacists were asked to rank the taste of these three products according to their experience from the best to the worst. Results: All suspension products had a CM concentration not less than 98% of the label amount. The ET results coupled with the principal component analysis (PCA) showed a very clear discrimination of the samples with different distances between groups (p-values < 0.001). Suspensions were in the following order in terms of taste: Klacid® > K1 > K2. Moreover, The pattern discrimination index between (K1 and Klacid®), (K1 and K2) and (Klacid® and K2) were 8.81%, 65.75%, and 71.94%, respectively which suggests that K1 and Klacid® are the most similar preparations in terms of taste. Interestingly, these results were in excellent agreement with the pharmacist ranking and patient acceptance test. Conclusions: The evaluated preparations showed significantly different taste within the order of Klacid® > K1 > K2, as suggested by both the ET and in vivo results. Moreover, our results confirm the capability of alpha-astree ET in the taste assessment of oral suspensions and in predicting volunteer responses, which highlights its beneficial use as an in vitro taste assessment tool and as an alternative to human-based taste evaluations.

Quantification of active ingredients in pharmaceutical suspensions by FT Raman spectroscopy

A method for quantitative determination of nifuroxazide, acetaminophen, ibuprofen and naproxen in commercial oral suspensions containing active compounds in the 1.7–4.0% (w/w) range is described. Partial least squares regression and counter-propagation artificial neural network models were built and validated. The lowest relative standard error of prediction values was found for the strongest scattering nifuroxazide suspensions. Commercial suspensions were quantified with recovery in the 99.3–101.2% and the 98.2–100.2% range, applying partial least squares and artificial neural network modeling techniques, respectively.

Real-Time PCR Detection of Burkholderia cepacia in Pharmaceutical Products Contaminated with Low Levels of Bacterial Contamination.

A real-time polymerase chain reaction (RT-PCR) assay was developed to detect Burkholderia cepacia in pharmaceutical products contaminated with low levels of bacteria. Different pharmaceutical suspensions were artificially contaminated with B. cepacia, Escherichia coli, Staphylococcus aureus, and Bacillus megaterium After a 24 h incubation in trypticase soy broth with Tween 20, samples were streaked on mannitol salt, phenyl ethyl alcohol, eosin methylene blue, MacConkey, and pseudomonas isolation agar. Microbial DNA was extracted from each sample by using a Tris-EDTA, proteinase K, Tween 20 buffer. Regular PCR targeting the 1.5 kilobases 16S rRNA eubacterial gene and cloning showed the predominant DNA in the extracted mix belonged to E. coli Selective media isolation of bacterial contamination showed B. cepacia only detected on pseudomonas isolation while eosin methylene blue and MacConkey detected only E. coli RT-PCR using primers PSL1 and PSR1 amplified a 209 bp 16S rRNA fragment using a Roche LightCycler 96® system with SYBR green I, a common double-stranded binding dye. The cycle at which fluorescence from amplification exceeds the background fluorescence was referred to as quantification cycle. All samples were found to be positive by standard microbiological testing and RT-PCR. B. cepacia was detected within 30 h in all contaminated samples using RT-PCR. Based upon standard curve analysis of B. cepacia DNA, the minimum DNA concentration that could be detected was 10 fg/uL with a correlation value of 0.98. RT-PCR detection of B. cepacia allowed faster quality control analysis, corrective actions, and process optimization.LAY ABSTRACT: A real-time polymerase chain reaction (RT-PCR) assay was developed to detect Burkholderia cepacia in pharmaceutical products contaminated with low levels of bacteria. B. cepacia is the number one reason for microbial contamination recalls of non-sterile drug products in the USA. RT-PCR using primers PSL1 and PSR1 amplified a 209 bp 16S rRNA fragment using a Roche LightCycler 96® system with SYBR green I, a common double-stranded binding dye. All samples were found to be positive by standard microbiological testing and RT-PCR. B. cepacia was detected within 30 h in all contaminated samples using RT-PCR. RT-PCR detection of B. cepacia allowed faster quality control analysis, corrective actions, and process optimization.

Study of Rheology and Polymer Adsorption Onto Drug Nanoparticles in Pharmaceutical Suspensions Produced by Nanomilling

Nanosuspensions provide a drug delivery approach to cope with erratic absorption of poorly water-soluble compounds. Despite extensive research over the last years, there are still open pharmaceutical challenges so it is often unclear how quality attributes such as viscosity and physical stability are generated, which requires a more thorough study of the colloidal structures and interactions in nanosuspensions. In this study, diffusing wave spectroscopy and microfluidics-based rheology were used for the first time to assess pharmaceutical nanosuspensions that were obtained by wet milling. Further sample characterization following centrifugation was based on optical rotatory dispersion and conductivity experiments. Ketoconazole was selected as model drug in the presence of sodium dodecyl sulfate and hydroxypropyl cellulose as anionic and steric stabilizer, respectively. The results unexpectedly showed that the investigated nanosuspensions did not behave as Einstein-like suspensions because a viscosity decrease was evidenced for increased drug load. This effect was attributed to the polymer that formed a dominating network in the bulk solution from where adsorption occurred onto particle surfaces. This depletion of bulk polymer caused the observed rheological finding. Further colloidal research should be invested into different pharmaceutical nanosuspensions to gain a more complete structural understanding and to harness their full technological potential.

Characterization and Evaluation of the Suspending Potentials of Corchorus olitorius Mucilage in Pharmaceutical Suspensions

Characterization and Evaluation of the Suspending Potentials of Corchorus olitorius Mucilage in Pharmaceutical Suspensions

Feasibility of Focused Beam Reflectance Measurement (FBRM) for Analysis of Pharmaceutical Suspensions in Preclinical Development.

This study examined the use of focused beam reflectance measurement (FBRM) for qualitative and quantitative analysis of pharmaceutical suspensions with particular application to toxicology supply preparations for use in preclinical studies. Aqueous suspensions of ibuprofen were used as prototype formulations. Initial experiments were conducted to examine the effects of operational conditions including FBRM probe angle, probe location, and mixing (method and rate of mixing) on the FBRM analysis. Once experimental conditions were optimized, the homogeneity and sedimentation-redispersion of particles in the suspensions were assessed. Ibuprofen suspension under continuous agitation was monitored using FBRM for 60h to study particle size change over time. Another study was performed to determine if particle count rates obtained by FBRM could be correlated to suspension concentration. The location and the angle of the FBRM probe relative to the beaker contents, and the rate and the method of mixing the suspension were found to be sensitive parameters during FBRM analysis. FBRM was able to monitor the process of particle sedimentation in the suspension. The attrition of ibuprofen particles was detectable by FBRM during prolonged stirring with an increase in the number of smaller particles and decrease in the number of larger particles. A strong correlation was observed between particle count rate by FBRM and ibuprofen concentration in the suspension. Also, change in content uniformity in the suspension at different locations of the beaker was represented by FBRM particle count. Overall, FBRM has potential to be a useful tool for qualitative and quantitative analysis of pharmaceutical suspensions.

FORMULATION AND BIO-AVAILABILITY PARAMETERS OF PHARMACEUTICAL SUSPENSION

The suspension is a biphasic liquid or semi-solid dosage form where the finely divided insoluble solid drug particles are homogeneously dispersed in a liquid or semi-solid medium. The solid drug particles act here as the dispersed phase and the liquid or the semi-solid as the dispersion medium. Suspensions contribute to pharmaceutical dosage form development by supplying drugs that are insoluble in all acceptable medium and often distasteful. Suspension translates such drugs into more bio-available form when compared to capsules, tablets, coated tablets, enteric coated tablets and sustained release products. The dosage form is palatable to the patient and many are doing well when applied to the skin or mucous membrane. This particular dosage form is also applied for injecting drugs into the systemic circulation. Therefore, pharmaceutical suspension finds its application through three different routes of administration namely oral, externally applied suspension and injectable one. The success of any dosage form largely depends on formulation parameters and the factors that influence the bioavailability which ultimately dictate the therapeutic success of the formulated dosage form. Hence, it is obvious to discuss the formulation parameters and the factors influencing bioavailability of suspension for the therapeutic success of it.

An Overview on Stability of Extemporaneously Prepared Pharmaceutical Suspension

Aim: The aim of this study was to write review on stability studies of extemporaneous preparations. Materials and methods: Different methods are used for checking stability studies, depending on the nature of the preparations, like visual inspection, pH checking, different temperature storage, and HPLC. Results: It was found that the stability concern with the pharmaceutical suspensions includes the variation in both physical and chemical properties. Therefore, it is most important that formulator must ensure the efficacy of the formulation throughout the shelf life period. In this review article, method used for stability checking is valid and up to mark, so patient can use these extemporaneous preparations according to recommended period of time. Conclusion: We can conclude of our Stress studies that these suspensions cannot be stored over long period of time (average 90-120 days); but they are stable below 120 days (depending on the preparation) so we can have used these preparations because there is no stability issue if used in within recommended time-period, undeniably extemporaneously prepared suspensions can be a helpful for pediatric, geriatric and unconscious patients in drug dosing.

The Dangers of Dilution When Measuring Water Based Pharmaceutical Suspensions and How Nanoflex Overcomes these Obstacles

Dynamic Light Scattering (DLS) has been an important tool for determining particle size distributions in fine particulate material suspensions, micro emulsions and Nano-scale matter in general for 50 years. Many Nano scale materials are measured in non-aqueous media and as long as we know the viscosities in these media at 2 different temperatures, then the analysis are relatively simple. However most pharmaceutical suspensions are water based and the key danger is not in the sampling but the chemistry. When measuring the size of particles, a study of their zeta potential in advance is extremely important as a high zeta potential is indicative of a stable product whilst a low zeta potential is indicative of an unstable product likely to agglomerate. When two particles have a high zeta potential they repel each other like 2 negative or positive magnets so they are not attracted to each other thus leading to a stable solution. When a sample is diluted dramatic changes to its zeta potential can occur especially when the dilution causes the zeta potential to approach the Iso Electric Point (IEP-0 m Volts). There are a number of effects which may cause the zeta potential to decrease towards 0 mV after dilution; we will cover pH, salt concentration and polyelectrolyte or surfactant concentration. There are 2 approaches to take when encountering this problem, The first approach requires full knowledge of the suspensions pH, salt concentration and volume % concentration of the surfactant such that care in dilution may be effected (Prevention). The second involves technological advances (Prevention and Cure) which are unique and employs a method which in most pharmaceutical applications renders the need to dilute redundant. By measuring the suspension at full concentration, all potential chemistry problems are negated.

EVALUATION OF THE SUSPENDING PROPERTIES OF A NEW PLANT GUM IN SULPHAMETOXAZOLE FORMULATIONS

Suspension dosage forms require the use of suspending agents in order to deliver a uniform dose of the active ingredient. The purpose of this study is to investigate the properties of a new plant gum as a cheap and effective natural polymer in the formulation of pharmaceutical suspensions. The gum obtained from the incised trunk of Cedrela odorata (family Meliaceae) was compared with hydroxypropylmethylcellulose and gelatin in Sulphamethoxazole suspension formulations at concentrations of 1.0 – 4.0%w/w. Assessment parameters were sedimentation volume, flow rate, viscosity and the effect of temperature on these parameters. The suspending characteristics of Cedrela gum compared well with that of hydroxypropylmethylcellulose in term of sedimentation volume, flow rate and viscosity and the natural gum could be used as a substitute in pharmaceutical suspensions.

Formulation and Evaluation of Diclofenac Suspension by Using Natural Suspending Agents

The purpose of this study is to search for cheap and effective natural excipients that can be used as an effective alternative for the formulation of pharmaceutical suspensions. In this research natural suspending agents were selected for the study. Gum acacia, compound tragacanth powder and starch were used. The pharmaceutical oral suspensions were prepared by using diclofenac as a model drug by using potassium chloride as flocculating agent. Diclofenac suspensions were prepared with different concentrations (2%, 3%, and 4%w/v) of each suspending agents like compound tragacanth powder, gum acacia and starch. Characterizations of the suspensions were carried out for sedimentation volume, degree of redispersibility, pH, viscosity and flow rate. As per the obtained results, compound tragacanth powder possesses better characteristics as a suspending agent compared to all other natural suspending agents. The results showed that sedimentation volume and viscosity were found to be directly proportional to the concentration of the suspending agents. The compound tragacanth powder was found to have a promising potential for use as a suspending agent in a concentration range of 24%w/v.