Dissolution Efficiency Values Research Articles

A Metformin-Ferulic Acid Salt with Improved Biopharmaceutical Parameters

Though ferulic acid presents great hypoglycemic potential, it possesses limited aqueous solubility, and low oral bioavailability. When associated with metformin, the first-choice drug in Type 2 diabetes treatment, FA demonstrates synergistic hypoglycemic effects, however, it also causes certain undesirable dose-related effects. This study aimed to develop a new ferulic acid - metformin multicomponent system, and incorporate it into a solid dosage form with improved biopharmaceutical parameters. A novel metformin: ferulate (1:1) salt (MFS) was produced, which was properly characterized using differing analytical techniques, including single crystal analysis. Also during the course of the study, a new polymorph of the metformin free base was observed. The MFS was obtained using solvent evaporation methods, which achieved high yields in reproducible process, as well as a 740-fold increase in ferulic acid aqueous solubility. The MFS tablets developed met quality control requirements for this dosage form, as well as revealing excellent performance in vitro dissolution tests, presenting dissolution efficiency values of 95.4 ± 0.5%. Additionally, physicochemical instability was not observed in a study at 40 °C for 3 months for both MFS powder and its tablet form. The MFS product developed is a promising candidate for further Type 2 diabetes clinical study.

Dissolution Enhancement of Indomethacin through Binary and Ternary Solid dispersions and Inclusion Complexes – A Comparative Evaluation

Dissolution of drugs is a prerequisite in the development of their oral dosage forms with satisfactory bioavailability. In this investigation, solid dispersion of the model drug indomethacin in gelucire (50/13) and inclusion complexation in sulfobutyl ether beta cyclodextrin are employed to enhance the dissolution. Fast dissolving products (F1-F8) of indomethacin are prepared by different methods such as solvent evaporation, freeze drying and kneading and comparatively evaluated. The ternary and binary systems of the products are prepared and evaluated for their efficiency in increasing the dissolution. The dissolution efficiency values (DE30) were found to be higher for solid dispersions (73.34%) and inclusion complexes (53.12%) than the pure drug indomethacin (3.32%). The x ray diffraction and differential scanning calorimetry studies revealed that the crystalline drug is converted into an amorphous form in the dispersions and inclusion complexes. Soluplus and gelucire are employed as ternary components in the solid dispersions and inclusion complexes respectively and are found to be resulting in ternary systems which were found to be superior to the binary systems. A 22 full factorial experimental design in order to investigate the combined influence of method of preparation and nature of the product. It was observed that the method of preparation and nature of the product (a ternary system or a binary system) will influence the extent of improvement of dissolution of the drug.

Influence of dispersing solvent on curcumin dissolution from solid dispersions prepared using hydroxypropyl methylcellulose-polyvinylpyrrolidone K30

Background: Preparation of lipophilic compounds into solid dispersion formulations (SDs) has been credited with increasing their dissolution rate. Understanding the role of the dispersing solvent is crucial to the SDs preparation. Drug/carrier-solvent immiscibility may decrease the dissolution rate. Aim: This work aimed to study the effect of different dispersing solvents on a curcumin dissolution. Method: A solvent evaporation method was used in the SD preparation. The formulation was prepared at 30% w/w drug load contained Curcuma longa and a carrier mixture of Hydroxy Propyl Methylcellulose (HPMC)/ Polyvinylpyrrolidone K30 (PVP K30). As for the dispersing solvent, the study used ethanol, ethyl acetate, and ethanol/ethyl acetate solvent mixture. The dissolution profile was obtained and analysed for the dissolution-efficiency (DE). Result: The DE values of 38.5%, 37.8%, and 32.0% were obtained using ethanol, ethyl acetate, and ethanol-ethyl acetate mixture. Conclusion: The results show that there is a significant impact of using different SD solvents on curcumin dissolution.

Modulating nimodipine crystallinity for enhancing dissolution: development of geriatric-friendly dosage form

Background: Instant disintegration of oral disintegrating tablets (ODTs) provides greater chance for buccal absorption, avoiding presystemic metabolism of nimodipine. In addition, ODT can be easily dispersed in suitable liquid before delivery via nasogastric tube in critical care setting. Objective: The objective was to improve nimodipine dissolution rate with the goal of developing ODTs for elderly patients, especially those experiencing neurological deficits. Methods: Drop assisted co-grinding of nimodipine with glycine (at molar ratios 1:1, 1:2 and 1:3) or tartaric acid (at molar ratios 1:0.5, 1:1, 1:2, 1:3, and 1:4) was performed. Solid state characterization and in vitro dissolution studies were employed. The optimized formulations were employed to prepare ODTs using suitable excipients. Results: The prepared formulations improved drug dissolution compared to unprocessed and wet ground nimodipine. Fourier–transform infrared spectroscopy, differential scanning calorimetry (DSC), powder X-ray diffraction and scanning electron microscopy suggested transformation of the crystalline structure after co-processing. This was due to salt formation in case of tartaric acid and formation of new crystalline species/ size reduction in case of glycine. These changes were associated with dissolution enhancement. Formulations with highest release efficiency (nimodipine and glycine a molar ratio of 1:1 or nimodipine and tartaric acid at molar ratio of 1:3) were successively incorporated in ODTs which showed fast liberation of nimodipine and dissolution efficiency values of 76 + 0.6 % and 73.3 + 1.7 % for the tablets containing glycine or tartaric acid respectively. Conclusion: The study introduced simple co-grinding approach for dissolution enhancement of nimodipine with high scaling up potential. The developed tablets will increase patient compliance with expected improved bioavailability.

Impact of Tablet Shape on Drug Dissolution Rate Through Immediate Released Tablets.

Purpose: The aim of this study was to evaluate the influence of the geometric shape on the dissolution rate of the domperidone, a drug model for immediate release dosage form. In this regard, a lack of sufficient information about the effective dissolution rate of the drugs regarding their shapes has made this issue an interesting subject for researchers. Methods: For this purpose, three tablet shapes, namely flat and biconvex both in a round and oblong shapes, with different four sizes were modelled for the preparation of domperidone tablet. In vitro dissolution test was accomplished using a USP dissolution apparatus II. The drug dissolution rate was assessed by calculating various dissolution parameters; e.g., dissolution efficiency (DE), mean dissolution rate (MDR), mean dissolution time (MDT), and difference and similarity factors (f1 and f2 ). Results: Regarding the disintegration time, the larger tablets showed a faster disintegration time. When the size of the tablets was smaller, the amount of released drug was significantly decreased. In addition, #9 tablets with a flat or biconvex geometry had obvious effects on the DE values. Generally, biconvex tablets had higher DE percentage than the flat tablets. Conclusion: Noticeable differences in dissolution parameters by considering the different geometric shapes play an important role in the drug release kinetics which makes a significant effect on quick onset of action in oral administration.

DISSOLUTION PROPERTIES OF A DOLOMITE CONTAINING ZINC ORE IN SODIUM HYDROXIDE SOLUTIONS

In this work, the dissolution properties of a dolomite containing zinc carbonate (smithsonite) ore
 sample having 24.22% ZnO were determined in sodium hydroxide solutions using X-ray diffraction
 (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermal (TG/DTA) and chemical analyses
 methods. It was observed that the dissolution efficiency value of zinc continuously increased with
 the increase of sodium hydroxide concentration from 1 to 4 M and the highest zinc dissolution
 efficiency of 70.7% was reached after dissolution in 4 M NaOH solution at temperature of 298 K.
 The XRD, FT-IR, TG/DTA and chemical analyses of undissolved solids obtained after dissolution
 of ore sample in 4 M NaOH solution at 298 K revealed that the smithsonite phase in the sample
 completely dissolved whereas the main gangue mineral dolomite remained practically unaffected,
 showing the selectivity of sodium hydroxide solution considering zinc dissolution. Although the
 smithsonite phase in the sample totally dissolved, hundred percent zinc dissolution efficiency
 could not be reached, which may indicate the presence of zinc in the gangue components, i.e.
 dolomite, clay minerals etc., of the studied ore sample.

Preparation and Characterization of Poloxamer 407 Solid Dispersions as an Alternative Strategy to Improve Benznidazole Bioperformance

Benznidazole (BZL), the first line drug for Chagas disease treatment, presents a low solubility, limiting the possibilities for its formulation. In this work, solid dispersions' (SDs) technology was exploited to increase BZL kinetic solubility and dissolution rate, seeking for an improvement in its bioperformance. A physical mixture (PM) and an SD using Poloxamer 407 as carrier were prepared and characterized. Dissolution tests were performed, and data were analyzed with the lumped model, which allowed to calculate different parameters of pharmaceutical relevance. A bioactivity assay was also carried out to probe the SD anti-trypanocidal activity. Among the most relevant results, the initial dissolution rate of the BZL SD was near 3, 4 and about 400-fold faster than the PM, a commercial formulation (CF) and an extracted BZL, respectivley. The times needed for an 80% of drug dissolution were 3.6 (SD), 46.4 (PM), and 238.7 min (CF); while the dissolution efficiency values at 30 min were 85.2 (SD), 71.2 (PM), and 65.0% (CF). Survival curves suggested that using Poloxamer 407 as carrier did not alter the anti-trypanocidal activity of BZL. These results allow to conclude that SDs can be an effective platform for immediate release of BZL in an oral administration.

DISSOLUTION BEHAVIOR OF CARBAMAZEPINE SUSPENSIONS USING THE USP DISSOLUTION APPARATUS 2 AND THE FLOW-THROUGH CELL METHOD WITH SIMULATED GI FLUIDS

Objective: To characterize the dissolution behaviour of carbamazepine generic suspensions using the USP Dissolution Apparatus 2 and the flow-through cell method with simulated gastrointestinal fluids as dissolution media.Methods: Tegretol® suspension and two generic formulations were tested. Dissolution studies were performed using the USP Apparatus 2 (75 rpm and 900 ml of dissolution medium) and the flow-through cell method (laminar flow at 16 ml/min). Simulated gastric fluid (SGF) (with and without pepsin) and simulated intestinal fluid (SIF) (without pancreatin) at 37.0±0.5 °C, was used as dissolution media. The quantity of dissolved carbamazepine was determined at 5 min intervals until reaching 60 min, at 285 nm. Percentage dissolved at 60 min, mean dissolution time, dissolution efficiency values (model-independent parameters), as well as t50% and t63.2% were calculated (model-dependent parameters). Values for all parameters were compared between the reference and generic formulations using one-way analysis of variance (ANOVA) following a Dunnett’s multiple comparison test. Dissolution data were also fitted to different fit models.Results: Since the first sampling time, the reference product had reached 100% of drug dissolved, which was determined using USP Apparatus 2. Nevertheless, significant differences in the three model-independent parameters of generic products were found (*P<0.05). Dissolution data obtained with the paddle apparatus were fitted to different kinetic equations; however, using the flow-through cell method and SIF without pancreatin, the three drug products were fitted to the same kinetic model (Gompertz). With ANOVA-based comparisons and the flow-through cell method, significant differences were found in dissolution data of generic product A versus reference at all sampling times (*P<0.05). The flow-through cell method and SGF with pepsin were the best options to discriminate among dissolution profiles.Conclusion: The flow-through cell method seems to be an adequate dissolution apparatus to characterize in vitrodissolution performance of Class II drugs manufactured as suspensions. For carbamazepine suspensions, SGF and laminar flow at 16 ml/min were the most appropriate conditions to discriminate among generic formulations. Given the physicochemical characteristics of carbamazepine and the environment in which the drug products were tested, these differences could be of clinical relevance.

IN VITRO RELEASE STUDIES OF CARBAMAZEPINE TABLETS AND BENZOYL METRONIDAZOLE SUSPENSIONS USING THE FLOW-THROUGH CELL APPARATUS AND SIMULATED GASTROINTESTINAL FLUIDS

Objective: To characterize the in vitro release of carbamazepine tablets and benzoyl metronidazole suspensions using the flow-through cell apparatus and simulated gastrointestinal fluids.Methods: Tegretol® tablets, Flagyl® suspension, and generic formulations of each were tested. Release studies were performed using an automated flow-through cell apparatus. Simulated gastric fluid (with and without pepsin) and simulated intestinal fluid (without pancreatin) at 16 ml/min and fasted state simulated intestinal fluid at 8 ml/min, all at 37.0±0.5 °C, were used as dissolution media. The quantity of dissolved carbamazepine and benzoyl metronidazole was determined at 5-min intervals until 60 min at 285 and 278 nm, respectively. Percentage dissolved at 60 min, mean dissolution time, dissolution efficiency values, and t10%, t25%, t50% and t63.2% were calculated. Mean values for all parameters were compared between the reference and generic formulations using Studentʼs t-test. Dissolution data were fitted to different kinetic models.Results: Simulated gastric fluid without pepsin showed no discriminative capability for carbamazepine tablets. Significant differences were observed between the reference and generic formulations for almost all parameters (*P<0.05). In some cases, the logistic model best described the in vitro release of both drugs.Conclusion: Using an apparatus and media that best simulates the gastrointestinal environment, we identified differences in the rate and extent of dissolution of both drugs that could help to optimise the design of interchangeable formulations. Based on the physicochemical characteristics of carbamazepine and benzoyl metronidazole and the conditions in which the formulations were tested, these differences could be of clinical relevance.

Influence of Testing Parameters on In Vitro Tramadol Release from Poloxamer Thermogels using the Immersion Cell Method.

The immersion cell is an in vitro performance test of drug release from semisolids. Several studies made use of immersion cells to investigate drug release from thermosensitive Poloxamer-based gels; however, specifications on the parameter setting are not yet available. Therefore, the aim of this study was to evaluate the influence of testing parameters on tramadol (a model drug) release, release rate, and dissolution efficiency (DE) from Poloxamer gels, using immersion cells. The thermosensitive gelling formulation showed batch-to-batch uniformity of gelling behavior, drug content, and drug release. The use of a membrane in the immersion cell resulted in slower drug release as compared to the absence of a membrane. Moreover, the faster the paddle rotation, the faster the drug release was. Membrane thickness showed a strong and significant linear relationship with corresponding DE values (Pearson's correlation coefficient, r=-0.9470; p=0.004). Factors that did not influence drug release include paddle position, i.e., distance between paddle and membrane, as well as membrane mean pore size. This study sets forth the importance of carefully controlling the following parameters including presence/absence of membrane, paddle rotation speed, and membrane thickness during the setup of release experiments from gels using immersion cells.

<i>In vitro</i> Evaluation of Trimethoprim and Sulfamethoxazole from Fixed-Dose Combination Generic Drugs using Spectrophotometry: Comparison of Flow-Through Cell and USP Paddle Methods

Purpose: To develop a first-order derivative spectrophotometric method for the determination of trimethoprim (TMP) and sulfamethoxazole (SMX) from fixed-dose combination generic products using a flow-through cell technique. Methods: Absorbance measurement was achieved at 247.8 and 257.9 nm for trimethoprim and sulfamethoxazole, respectively. USP Apparatus 4 with 22.6 mm cells, laminar flow at 16 ml/min, and 0.1 N HCl at 37 °C as dissolution medium, were used. Dissolution profiles were compared with modeldependent and independent methods. Results: All the products met the pharmacopeial dissolution criterion (Q ≥ 70 %, at 60 min), except SMX in two products (SC 400 mg and SB1 800 mg) using the flow-through cell (53.62 and 49.74 % dissolved, respectively). Using both USP apparatuses, significant differences in mean dissolution time and dissolution efficiency values were found (p < 0.05). All products were in line with Weibull’s kinetics and significant differences in derived parameters (Td) values were found (p < 0.05). Conclusion: Determination of TMP and SMX by derivative spectrophotometry can easily be employed for dissolution studies using the flow-through cell technique. However, it would be necessary to determine correlation with in-vivo test results in order to assure safe interchangeability. Keywords: Trimethoprim, Sulfamethoxazole, Flow-through cell method, First-order derivative spectrophotometry, Fixed-dose combination generic drugs

Sodium alginate as a potential carrier in solid dispersion formulations to enhance dissolution rate and apparent water solubility of BCS II drugs

The solid dispersion technique is the most effective method for improving the dissolution rate of poorly water-soluble drugs, however it depends on a suitable carrier selection. The work explored the use of the biopolymer sodium alginate (SA) as a potential carrier in solid dispersions (SD). The data demonstrated that SA was able to improve the biopharmaceutical properties of the BCS II drug telmisartan (TEL) of low solubility even using relative small drug:polymer ratio. A solid state grinding process was used to prepare the solid dispersions (SD) during 45min. The SD were prepared in different proportions of drug and carrier of 1:1, 1:3, 1:5, 1:7 and 1:9 (mass/mass). DSC, XRPD, FTIR and Raman confirmed the presence of molecular interactions between TEL and the carrier. FTIR supports the presence of hydrogen bonds between TEL and the carrier. SD_1:5, SD_1:7 and SD_1:9 enhanced the dissolution rate of the drug releasing more than 80% of the drug in just 30min (83%, 84% and 87%). The the t-test results demonstrated equal dissolution efficiency values for SD_1:7 and Micardis®, however the similarity (f2) and difference (f1) fit factors showed that the SD and Micardis® are statistically different. The physical stability studies demonstrated that SD using sodium alginate as a carrier remained unchanged during the period of 90 days at room temperature, showing that the sodium alginate acts as a good anti plasticizer agent, preventing the drug recrystallization.

Amalgamation of solid dispersion and adsorption technique

The objective of present investigation was to improve dissolution of ritonavir (RTV), a BCS Class II drug. Amalgamation of solid dispersion and melt adsorption technology was utilized for developing the formulation. Solid dispersion adsorbate (SDA) was prepared using combination of Lutrol F127, Transcutol HP and Labrasol as carriers and Neusilin as an adsorbent and flow inducer. The concept of design of experiments (DoE) was used in identifying the critical formulation factors. The optimised SDA was characterised by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis and X-ray diffraction studies. From the results obtained, it can be concluded that improvement in dissolution of RTV was due to hydrogen bonding of drug with Neusilin, micellar solubilisation of drug in carrier, improved wettability and reduction in the crystallinity. The dissolution efficiency value of optimised SDA is 41.68 % at 10 min time point which is three times the release of untreated drug. Convolution modelling was employed to get a predicted plasma drug concentration time profile.

Test of dissolution and comparison of in vitro dissolution profiles of coated ranitidine tablets marketed in Bahia, Brazil

Ranitidine is an antisecretory drug with H2 antagonist action useful in treating gastric and duodenal disorders. The dissolution test is used to obtain and compare dissolution profiles and establish similarities of pharmaceutical forms. The aim of this study was to compare the dissolution profiles of 150-mg coated ranitidine tablets of a reference drug (product A) and a generic (product B) and a similar (product C) drug marketed in Bahia, Brazil using a simple, fast and inexpensive ultraviolet method. Dissolution was determined using a USP type 2 apparatus at 50 rpm with 900 mL of distilled water at 37.0 ± 0.5 oC for 1h. The dissolution test was performed in compliance with the American Pharmacopoeia (USP-32). Dissolution efficiency and difference (f1) and similarity (f2) factors were calculated and evaluated. The proposed quantification methodology for drug dissolution test was validated, presenting accuracy, linearity and precision within the acceptance criteria. Products A, B and C showed dissolution efficiency values of 59.29, 73.59 and 66.67%, respectively. Factors f1 and f2 were calculated and showed that the profiles of products A, B and C were dissimilar. However, all the products released ranitidine satisfactorily, with at least 80% of the drug dissolved within 30 min.

Single non-ionic surfactant based self-nanoemulsifying drug delivery systems: formulation, characterization, cytotoxicity and permeability enhancement study

Single non-ionic surfactant based self-nanoemulsifying drug delivery system (SNEDDS) was formulated and characterised for poor water soluble drug, Atorvastatin calcium. Capmul MCM oil showing highest solubility for Atorvastatin calcium was selected as oil phase. Self-nanoemulsifying capacity of Cremophor RH 40, Cremophor EL, Tween 20, Tween 60, Tween 80 and Labrasol were tested for the selected oil. In vitro dissolution studies were performed and were characterized by t85% and dissolution efficiency (DE). Cytotoxicity of the formulations and permeation enhancement of the drug across caco-2 cell monolayer was assessed. Capmul MCM was found to be better nanoemulsified in decreasing order of Cremophor RH 40 > Cremophor EL > Tween 20 > Tween 60 > Tween 80. Values of droplet size (range 11–83 nm), polydispersity index (range 0.07–0.65); zeta potential (range −3.97 to −19.0) and cloud point (60–85°C) before and after drug loading proves the uniformity and stability of the formulations. SNEDDS formulated with Tween 20 surfactant showed enhanced dissolution with t85% and DE values at 10 min and 78.70, respectively. None of the formulation showed cytotoxicity at the concentration tested. Tween 20 based SNEDDS enhanced permeation of the drug as compared with pure drug across cell lines. It can be concluded that SNEDDS can be formulated by using single non-ionic surfactant system for enhance dissolution and absorption of poorly soluble drug, Atorvastatin calcium.

Oral self emulsifying powder of lercanidipine hydrochloride: Formulation and evaluation

The current investigation was aimed to improve the solubility of poorly soluble lercanidipine hydrochloride as self emulsifying powder (SEP). Liquid SEDDS of LCH was formulated with Capmul MCM L8 as oil, Tween (R) 80 as surfactant and PEG 400 as co surfactant after screening various vehicles. The prepared formulations were evaluated for self emulsifying ability and phase diagram was constructed to optimize the system. These systems were further characterized for globule size, effect of pH and robustness to dilution, cloud point, thermodynamic stability, surface morphology and drug release. The system was robust to different pH media and dilution volumes. The optimized system possessed a mean globule size of 169±06nm and cloud point of 76°C. The self emulsifying powder was prepared by adsorbing the liquid SEDDS on to neusilin as carrier. The SEP formulated was free flowing with similar emulsification characteristics as that of liquid SEDDS. The X-ray diffraction, Differential Scanning Calorimetric studies of SEP revealed transformation of crystalline structure of LCH because of its molecularly dissolved state in the liquid SEDDS. This was further confirmed by scanning electron microscopy. High dissolution efficiency value of SEP compared with pure drug indicated the increase in dissolution characteristics of LCH in SEP.

Effect of Accelerated-Aging Conditions on the Dissolution Stability of Ciprofloxacin Tablets

The aim of the present study was to evaluate and compare the influence of accelerated-aging conditions on the drug c ontent and in vitro dissolution stability of eleven different ciprofloxacin (CIP) 500-mg tablets obtained from pharmacies and hospitals in Argentina. CIP, a Class II/IV drug in the Biopharmaceutics Classification System, is a fluoroquinolone antibiotic agent used in the treatment of bacterial infections. CIP content was evaluated following USP (1) specifications. Dissolution efficiency (DE) was calculated from dissolution profiles that were performed according to the British Pharmacopoeia monograph for CIP tablets (2). This determination was performed at time zero and after three (3M) and six months (6M) of storage, according to ICH accelerated-aging conditions (40 °C/75% RH). Each formulation was compared with the reference at the specified times, using ANOVA in terms of DE and similarity factor f2. Furthermore, ANOVA for DE values was used to evaluate the effect of aging conditions on the dissolution stability within each formulation. Although the storage conditions examined in the study affected the dissolution behavior of all CIP formulations, they did not have a significant effect on chemical stability, with the exception of one formulation that showed undesirable performance in both chemical and dissolution stability.

In vitro food–drug interaction study: Which milk component has a decreasing effect on the bioavailability of ciprofloxacin?

The purpose of the present work was developing an in vitro dissolution test to highlight the possible molecular background causing ciprofloxacin (CPFX)–milk interaction. The in vitro dissolution of CPFX from film-coated tablets (Ciprinol ® 500 mg) was examined at different pH values, simulating certain parts of the gastrointestinal tract, in the presence of water, low-fat milk, casein- or calcium enriched water. In order to determine the amount of dissolved CPFX, solid phase extraction sample preparation followed by high performance liquid chromatography coupled with mass spectrometry was applied. Comparing the dissolution efficiency values in various media, it can be concluded, that casein has a more pronounced effect on the absorbable amount of the antibiotic at each pH value studied, than calcium. In the case of concomitant intake of CPFX film-coated tablet and milk or other dairy products not only the complexation with calcium, but also the adsorption of CPFX on the surface of proteins decreases the absorbable amount of CPFX.

Dissolution parameters for sodium diclofenac-containing hypromellose matrix tablet

Sodium diclofenac (SD) release from dosage forms has been studied under different conditions. However, no dissolution method that is discriminatory enough to reflect slight changes in formulation or manufacturing process, and which could be effectively correlated with the biological properties of the dosage form, has been reported. This study sought to develop three different formulae of SD-containing matrix tablets and to determine the effect of agitation speed in its dissolution profiles. F1, F2 and F3 formulations were developed using hypromellose (10, 20 and 30%, respectively for F1, F2 and F3) and other conventional excipients. Dissolution tests were carried out in phosphate buffer pH 6.8 at 37 °C using apparatus II at 50, 75 or 100 rpm. Dissolution efficiency (DE), T 50 and T 90 were determined and plotted as functions of the variables agitation speed and hypromellose concentration. Regarding DE, F2 showed more sensitivity to variations in agitation speed than F1 and F3. Increasing hypromellose concentration reduced DE values, independent of agitation speed. Analysis of T 50 and T 90 suggests that F1 is less sensitive to variations in agitation speed than F2 and F3. Most discriminatory dissolution conditions were observed at 50 rpm. Results suggest that the comparison of dissolution performance of SD matrix tablets should take into account polymer concentration and agitation conditions.

Dissolution test optimization for meloxicam in the tablet pharmaceutical form

Meloxicam is a broadly used drug in the therapeutics for the osteoarthritis and rheumatoid arthritis treatments in adults, and it is available in the Brazilian market, as tablet and capsule pharmaceutical forms. The present work aimed to establish conditions for accomplishment of the dissolution test of 15 mg meloxicam tablets (A and B test products), compared with the reference product, since there is no monograph about dissolution assays for meloxicam in official summaries. To optimize the conditions several parameters were tested and, according to obtained results, the use of pH 7.5 phosphate buffer (900mL, at 37 ± 0.5ºC) as dissolution medium, paddle method (apparatus 2), stirring speed of the dissolution medium at 100 rpm and collect time of 60 minutes were considered satisfactory. The samples were quantified by UV spectrophotometric method at 362 nm. The products presented kinetics of first-order. Dissolution efficiency values were of 83.25, 83.73 and 88.10% for the A, B and reference products, respectively. Factors f1 and f2 were calculated and similarity of the tested medicines was demonstrated. The dissolution test was validated presenting selectivity, linearity, precision and accuracy within of the acceptance criteria.