Circulating miR-206 and miR-1246 as Markers in the Early Diagnosis of Lung Cancer in Patients with Chronic Obstructive Pulmonary Disease.

Lung cancer (LC) is the most common cause of cancer death, with 75% of cases being diagnosed in late stages. This study aimed to determine potential miRNAs as biomarkers for the early detection of LC in chronic obstructive pulmonary disease (COPD) cases. Ninety-nine patients were included, with registered clinical and lung function parameters followed for 6 years. miRNAs were determined in 16 serum samples from COPD patients (four with LC and four controls) by next generation sequencing (NGS) at LC diagnosis and 3 years before. The validation by qPCR was performed in 33 COPD-LC patients and 66 controls at the two time points. Over 170 miRNAs (≥10 TPM) were identified; among these, miR-224-5p, miR-206, miR-194-5p, and miR-1246 were significantly dysregulated (p < 0.001) in COPD-LC 3 years before LC diagnosis when compared to the controls. The validation showed that miR-1246 and miR-206 were differentially expressed in COPD patients who developed LC three years before (p = 0.035 and p = 0.028, respectively). The in silico enrichment analysis showed miR-1246 and miR-206 to be linked to gene mediators in various signaling pathways related to cancer. Our study demonstrated that miR-1246 and miR-206 have potential value as non-invasive biomarkers of early LC detection in COPD patients who could benefit from screening programs.

Development and Optimization of a New UPLC-UV/MS Method through DoE and MLR for Detecting Substandard Drug Products to Treat Tuberculosis.

Drug products used for treating tuberculosis are one of the most widely reported medicines to be classified as falsified or substandard in low- and middle-income countries, representing a major hazard to health. The aim of this study was, firstly, to develop an ultra-performance liquid chromatography (UPLC) method which is able to analyze fixed combination tablets with up to four active pharmaceutical ingredients, including isoniazid, pyrazinamide, rifampicin, and ethambutol. Secondly, we aimed to optimize it through the design of experiments and multi-linear regression based on a central composite design and to validate it according to the guidelines of the International Conference on Harmonization. The application of this tools enabled the identification of the influential factors (flow rate, formic acid, and temperature) and their effects on the studied responses (retention factor and percentage for each drug) as part of the quality by design approach. The method proved to be to be linear in the range from 5.0 to 15 µg/mL for isoniazid, pyrazinamide, and rifampicin, being precise (<1%) and accurate (97−101%). In addition, the method validated for ethambutol proved to be linear from 1.4 to 4.2 µg/mL, as well as precise (0.54%) and accurate (97.3%). The method was stability indicated for all the active pharmaceutical ingredients studied and was able to detect two substandard formulations sampled on the African market.

Application of capability indices and control charts in the analytical method control strategy.

In this study, we assessed the usefulness of control charts in combination with the process capability indices, Cpm and Cpk , in the control strategy of an analytical method. The traditional X-chart and moving range chart were used to monitor the analytical method over a 2-year period. The results confirmed that the analytical method is in-control and stable. Different criteria were used to establish the specifications limits (i.e. analyst requirements) for fixed method performance (i.e. method requirements). If the specification limits and control limits are equal in breadth, the method can be considered "capable" (Cpm  = 1), but it does not satisfy the minimum method capability requirements proposed by Pearn and Shu (2003). Similar results were obtained using the Cpk index. The method capability was also assessed as a function of method performance for fixed analyst requirements. The results indicate that the method does not meet the requirements of the analytical target approach. A real-example data of a SEC with light-scattering detection method was used as a model whereas previously published data were used to illustrate the applicability of the proposed approach.

Development of an ultra high performance liquid chromatography method for determining triamcinolone acetonide in hydrogels using the design of experiments/design space strategy in combination with process capability index.

An ultra high performance liquid chromatography method was developed and validated for the quantitation of triamcinolone acetonide in an injectable ophthalmic hydrogel to determine the contribution of analytical method error in the content uniformity measurement. During the development phase, the design of experiments/design space strategy was used. For this, the free R-program was used as a commercial software alternative, a fast efficient tool for data analysis. The process capability index was used to find the permitted level of variation for each factor and to define the design space. All these aspects were analyzed and discussed under different experimental conditions by the Monte Carlo simulation method. Second, a pre-study validation procedure was performed in accordance with the International Conference on Harmonization guidelines. The validated method was applied for the determination of uniformity of dosage units and the reasons for variability (inhomogeneity and the analytical method error) were analyzed based on the overall uncertainty.

Oxidative Damage and Telomere Length as Markers of Lung Cancer Development among Chronic Obstructive Pulmonary Disease (COPD) Smokers.

Lung cancer (LC) constitutes an important cause of death among patients with Chronic Obstructive Pulmonary Disease (COPD). Both diseases may share pathobiological mechanisms related to oxidative damage and cellular senescence. In this study, the potential value of leucocyte telomere length, a hallmark of aging, and 8-OHdG concentrations, indicative of oxidative DNA damage, as risk biomarkers of LC was evaluated in COPD patients three years prior to LC diagnosis. Relative telomere length measured using qPCR and serum levels of 8-OHdG were determined at the baseline in 99 COPD smokers (33 with LC and 66 age-matched COPD without LC as controls). Of these, 21 COPD with LC and 42 controls had the biomarkers measured 3 years before. Single nucleotide variants (SNVs) in TERT, RTEL, and NAF1 genes were also determined. COPD cases were evaluated, which showed greater telomere length (p < 0.001) and increased serum 8-OHdG levels (p = 0.004) three years prior to LC diagnosis compared to the controls. This relationship was confirmed at the time of LC diagnosis. No significant association was found between the studied SNVs in cases vs. controls. In conclusion, this preliminary study shows that longer leucocyte telomere length and increased 8-OHdG serum levels can be useful as early biomarkers of the risk for future lung cancer development among COPD patients.

Drug Shelf Life and Release Limits Estimation Based on Manufacturing Process Capability.

Specification limits are the competence regulatory agencies, whereas the release limit is a manufacturer's internal specification to be applied at the time of batch release to assure that quality attributes will remain within the specification limits until the expiry time. The aim of this work is to propose a method to set the shelf life from drug manufacture process capacity and degradation rate, using a modified version of the proposed method by Allen et al. (1991) Two different data sets were used to do this. The first data set corresponds to analytical method validation to measure the insulin concentration in order to estimate the specification limits, whereas the latter set gathered information on stability data of six batches of human insulin pharmaceutical preparation. In this context, the six batches were divided into two groups: Group 1 (batches 1, 2, and 4) was used to estimate shelf life; Group 2 (batches 3, 5, and 6) was used to test the estimated lower release limit (LRL). The ASTM E2709-12 approach was applied to verify that the future batches fulfill the release criterium. The procedure has been implemented in R-code.

Trends in the Consumption of Antidepressant Drugs before and during the COVID-19 Pandemic in the Canary Islands, Spain: The Case of the Province of Las Palmas.

The use of antidepressants (ADs) has increased significantly as a result of COVID-19 and its consequences. However, there are some notable differences in the relative levels of use between geographical areas and population groups. The aim of this work is to assess the impact of COVID-19 on the consumption of ADs in the Canary Islands, focusing on the islands of Gran Canaria, Fuerteventura and Lanzarote, by analyzing the trends in prescriptions of ADs during the pandemic period (2020) compared to the pre-pandemic period (2016-2020). Data were extracted from the community pharmacy wholesaler at a population level. Consumption patterns are expressed as the number of defined daily doses per 1000 inhabitant/day. The overall consumption of DIDs was higher in Gran Canaria, mainly in urban areas and the capital. It was similar in both Lanzarote and Fuerteventura, but particularly localized in the capital, which are considered semi-urban areas. Lanzarote and Fuerteventura present the same pattern of prescription ADs use, whereas Gran Canaria is notably different. This finding was also observed in the more consumed active pharmaceutical ingredients, although small inter-island variations in the ranking and percentages were observed. Sertraline and escitalopram are two of the most prescribed N06AB ADs, whereas the most recent N06AX ADs such as venlafaxine, mirtazapine and desvenlafaxine are more commonly prescribed. These differences in prescription ADs can be explained by demographical characteristics, population size, the fact of living in an urban area and general medical practice. In this context, the COVID-19 pandemic did not have an impact on the overall trend of the use of ADs between 2016 and 2020 in the islands under study.

Opioid prescription patterns in the province of Las Palmas, Canary Islands, Spain (2016-2020): differences between urban and rural areas.

Introduction: The use of opioids has increased markedly in the past decades in European countries, especially for treatment of non-cancer pain including painful chronic musculoskeletal conditions. However, there are some notable differences in the relative levels of use between geographical areas and some distinct, context-specific patterns of weak and strong opioid use. The aim of this work is to describe real world trends in dosage forms and population exposure in the prescription opioid use on isolated geographically area: The Canary Islands of Gran Canaria, Lanzarote and Fuerteventura, Spain. For this, several factors such as living in a rural or urban area, population over 65 years of age, population density or socioeconomic status were analyzed. Methods: Data were extracted from the wholesalers who supply the community pharmacies at the population level. Prescription opioid use was measured as defined daily doses (DDD) per 1,000 inhabitants per day. A model based on covariance analysis with two nested fixed factors and one co-variable was used for contrast analysis at different level. Results: The overall DDD per 1000 inhabitants per day and year variation rate in Spain was very similar to that obtained for Gran Canaria and Fuerteventura (0.967 vs. 1.006), although the levels of dispensation were different (14.75 versus 18.24 for Gran Canaria and 12.7 for Fuerteventura, respectively). Lanzarote is completely different in all issues, where the opioid consumption rate remained stable during the study period, but with a decreasing tendency. The dispensation level of strong opioids varied between islands, from 56.41% for Fuerteventura vs. 17.61% for Gran Canaria, although these values remained stable. Tramadol with acetaminophen and Tramadol in monotherapy were the most consumed forms of the weak opioids, whereas Buprenorphine was the most used strong opioid followed by Fentanyl, although demand for it varied between islands, the transdermal formulations were the most frequent pharmaceutical preparation. Conclusion: The differences in prescription opioid use are most likely explained by the opioid prescribing practices in each island, whereas factors such urbanicity level, population age, population density and status socioeconomic does not help to explain the differences in prescription opioid use across rural and urban areas.

Opioid use trends in Spain: the case of the island of La Gomera (2016-2019).

This study is an evaluation of prescription opioid use on the island of La Gomera, a mainly rural area, during the period 2016-2019 at various levels. Data were extracted from the wholesalers who supply the community pharmacies at the population level. Prescription opioid use was measured as defined daily doses per 1,000 inhabitants/day (DID) and by the number of units sold per 1,000 inhabitants and year (units sold). This provided an island total of La Gomera's overall prescription of opioids and its rate of change, as well as differences in prescribing at the municipal and health area level. Tramadol with acetaminophen and tramadol in monotherapy were the most consumed by "units sold" parameter, which accounted for 69.48% and 18.59% of the total. The situation was similar for DID, although with lower percentages, but a significant increase was observed in the use of fentanyl and buprenorphine, around 15% in each case. The balance between the uses of weak or strong opioids was different in La Gomera compared to that of Spain as a whole. In Spain, almost 70% of the prescriptions were for weak opioids compared to 58.67% in La Gomera. Fentanyl was the most used strong opioid (16.10%) followed by tapentadol and buprenorphine, around 5% each, whereas in La Gomera, buprenorphine was the most consumed (15.75%) followed by fentanyl (14.87%) and tapentadol (5.82%). These differences in prescription opioid use are most likely explained by prescriber characteristics, whereas the population age, socioeconomic status, or living in rural/urban area are not decisive determinants.

Pitavastatin loaded nanoparticles: A suitable ophthalmic treatment for Acanthamoeba Keratitis inducing cell death and autophagy in Acanthamoeba polyphaga.

Statins are effective sterol lowering agents with high amoebicidal activity. Nevertheless, due to their poor aqueous solubility, they remain underused especially in eye drop formulation. The aim of the present study is to develop Pitavastatin loaded nanoparticles suitable for ophthalmic administration and designed for the management of Acanthamoeba Keratitis. These nanocarriers are aimed to solve both the ophthalmic route-associated problems and the limited aqueous drug solubility issues of Pitavastatin. Nanoparticles were obtained by a nanoprecipitation-solvent displacement method and their amoebicidal activity was evaluated against four strains of Acanthamoeba: A. castellanii Neff, A. polyphaga, A. griffini and A. quina. In Acanthamoeba polyphaga, the effect of the present nanoparticles was investigated with respect to the microtubule distribution and several programmed cell death features. Nanoparticles were able to eliminate all the tested strains and Acanthamoeba polyphaga was determined to be the most resistance strain. Nanoparticles induced chromatin condensation, autophagic vacuoles and mitochondria dysfunction.

Limitations of the quality range approach in analytical similarity assessment: Effect of mean shift and relative variability.

Recently in 2019, the United States Food and Drug Administration (FDA) circulated a new draft guidance for comparative analytical assessment. They suggest the use of quality range (QR) methods. In this article, selection of the k value, and the effect of mean shifts and relative variability are evaluated. These are expressed as a ratio between the two standard deviations of the tested product and the reference product, σT/σR. In a second step, the two modified versions of the QR method proposed by Son et al. (2020) are also analysed under several scenarios, through simulation studies using real data from a biotechnology company and our own data for bevacizumab. Results indicate that k has a great impact on the probability of passing similarity tests. Pass rates higher than 90 % can be achieved for small relative variabilities (σT/σR ≤ 0.6) and large mean shifts (≈4%) by using k = 3. The situation is totally different for k = 2: the pass rate is higher than 90 % for scenarios with small (<0.5 %) or no differences between the means of the two products, but this percentage decreases by up to 50 % for σT/σR = 1. Effectiveness in detecting the various scenarios was quantified by calculating the probability curves of passing the similarity test, as a function of the two variables for each k value. Alternative methods present the same limitations but with different magnitude in comparison with QR, this being most pronounced in the plausibility-interval QR method.

New Quality-Range-Setting Method Based on Between- and Within-Batch Variability for Biosimilarity Assessment.

Analytical biosimilarity assessment relies on two implicit conditions. First, the analytical method must meet a set of requirements known as fit for intended use related to trueness and precision. Second, the manufacture of the reference drug product must be under statistical quality control; i.e., the between-batch variability is not larger than the expected within-batch variability. In addition, the quality range (QR) method is based on one sample per batch to avoid biased standard deviations in unbalanced studies. This, together with the small number of reference drug product batches, leads to highly variable QR bounds. In this paper, we propose to set the QR bounds from variance components estimated using a two-level nested linear model, accounting for between- and within-batch variances of the reference drug product. In this way, the standard deviation used to set QR is equal to the square root of the sum of between-batch variance plus the within-batch variance estimated by the maximum likelihood method. The process of this method, which we call QRML, is as follows. First, the condition of statistical quality control of the manufacture process is tested. Second, confidence intervals for QR bounds lead to an analysis of the reliability of the biosimilarity assessment. Third, after analyzing the molecular weight and dimer content of seven batches of a commercial bevacizumab drug product, we concluded that the QRML method was more reliable than QR.

New administration model of trans-chalcone biodegradable polymers for the treatment of experimental leishmaniasis.

The present study was designed to investigate a new administration model and the antileishmanial activity of a semi-synthetic chalcone, benzylideneacetophenone (trans-chalcone). The antileishmanial activity of this product was first tested in vitro against promastigotes of L. braziliensis, L. tropica, L. infantum and L. amazonensis. An in vivo experiment was carried out using subcutaneous administration of trans-chalcone and implants of synthetic biodegradable polymers, polylactic acid (PLA) and polylactic/glycolic acid (PLGA). This compound showed potent inhibitory effects on the growth of all Leishmania strains examinated. Subcutaneous administration of trans-chalcone at a single dose of 4 mg/kg of body weight reduced lesion development in mice infected with L. amazonensis. A similar inhibition of the lesion growth in mice treated with trans-chalcone and pentamidine was observed. PLA and PGLA implants of trans-chalcone at 4 mg/kg were administered to mice infected with L. amazonensis. PLGA implants induced a highest reduction in the lesion size (31.25%) than PLA implants (10.75%). Treatment in vitro with trans-chalcone at IC50, completely inhibited the pathogenicity of this parasite in vivo. The development of this model provides a new practical technique for delivering drugs and can be useful for experimental leishmaniasis treatment.

Pre-study and in-study validation of a size-exclusion chromatography method with different detection modes for the analysis of monoclonal antibody aggregates.

Size exclusion chromatography (SEC) with different detection modes was assessed as a means to characterize the type of bevacizumab aggregate that forms under thermal stress, quantitatively monitoring the aggregation kinetics. The combination of SEC with light-scattering (SEC/LS) detection was validated using in-study validation process. This was performed by applying a strategy based on a control chart to monitor the process parameters and by inserting quality control samples in routine runs. The SEC coupled with a differential refractive-index detector (SEC/RI) was validated using a pre-study validation process in accordance with the ICH-Q2 (R1) guidelines and in-study monitoring in accordance with the Analytical Target Profile (ATP) criteria. The total error and ß-expectation tolerance interval rules were used to assess method suitability and control the risk of incorrectly accepting unsuitable analytical methods. The aggregation kinetics data were interpreted using a modified Lumry-Eyring model. The true order of the reaction was determined using the initial-rate approach. All the kinetic data show a linear Arrhenius dependence within the studied temperature range. The Arrhenius approach over-predicted the aggregation rate for 5°C, but provides an idea of the aggregation process and amount of aggregate formed. In any case, real-time stability data are necessary to establish the product shelf-life.

Fitting bevacizumab aggregation kinetic data with the Finke-Watzky two-step model: Effect of thermal and mechanical stress.

Size exclusion chromatography with light scattering detection (SEC-MALLS) was assessed as a means to characterize the type of bevacizumab aggregates that form under mechanical and thermal stress, quantitatively monitoring the aggregation kinetics. The analytical method was monitored and verified during routine use at two levels: (1) the "pre-study" validation shows that the method is specific, linear, accurate, precise, robust and stability indicating; (2) the "in-study" validation was verified by inserting quality control samples and the use of control charts, indicating that the analytical method is in statistical control and stable. The aggregation kinetics data were interpreted using a modified Lumry-Eyring model, but the quality of the fit can be considered poor (R(2)>0.96), especially at higher temperatures. This indicates that the order of the reaction could not be reliably determined, suggesting a different degradation mechanism. The kinetic data set also fit the minimalistic Finke-Watzky (F-W) 2-step model, with an excellent quality of fit (R(2)>0.99), yielding the first quantitative rate constant for the steps of nucleation and growth in bevacizumab aggregation. The bevacizumab pharmaceutical preparation contains (initially) dimers, approximately 1.6% of bevacizumab total concentration, and the effect on aggregation kinetics of seeding was analyzed using the F-W 2-step model assuming [B]0≠0 (for the seeded case). The results suggested that the seeding had no impact on aggregation kinetics. Furthermore, the Arrhenius equation cannot be used to extrapolate the shelf-life since no linear temperature dependence of the rate constant was found within the temperature range. Although the real-time stability data provides the basis for determining the product shelf-life, predictive methodologies such as Vogel-Tammann-Fulcher (VFT) or the Arrhenius approach can be misleading and result in overestimates of the product shelf-life. However, they can be successfully applied to fixing the lower and upper limits of the aggregation rate, i.e. the best and worst-case scenarios regarding the aggregation potential of the product. In conclusion, the present study evaluates the first application of the F-W 2-step model to fitting and interpretation of experimental aggregation data for bevacizumab pharmaceutical preparations, using SEC-MALLS in this context.

Characterization of antimalarial SPf66 peptide using MALDI-TOF MS, CD and SEC.

SPf66 is the first chemically synthesized peptide to elicit a partial protective immune response against malaria. Size-exclusion chromatography (SEC) with multi-angle laser light-scattering (MALLS) detection and hydrogen/deuterium (H/D) exchange monitored by (matrix-assisted laser desorption/ionization) MALDI-TOF (time-of-flight) mass spectrometry (MS) were used to assess the conformation and stability in aqueous solution after storage at different temperatures. Moreover, the feasible conformational changes of this peptide were also measured by circular dichroism (CD)-spectroscopy. The absolute molecular weight of SPf66 monomer and dimer species were 4765 and 8960Da using SEC with MALLS detection, and 4643 and 9490Da by MALDI-TOF MS, the discrepancy being between both methods lower than 5.7%, a value quite close to those found in other proteins. The results from H/D exchange monitored by MALDI-TOF MS and CD-spectroscopy show that the SPf66 monomer lacks ordered structure, whereas the SPf66 dimer species presents segments of secondary structure as a determined by CD measurements.

Chromatographic characterization of synthetic peptides: SPf66 malaria vaccine.

The development and validation of a quantitative size-exclusion chromatography (SEC) method for SPf66 malaria vaccine was achieved. The results show the reliability of the analytical method for the intended use. SPf66 malaria vaccine characterization was perforrmed using both relative techniques such as the conventional SEC and absolute techniques: mass spectrometry and multi-angle laser-light scattering detection. The relative and absolute molecular masses were in the 4600-18,000 Da range. The results clearly indicate the presence of the monomer and dimer species, whereas the third species could be the trimer or tetramer.

Applications of multi-angle laser light-scattering detection in the analysis of peptides and proteins.

The proliferation of new peptides and proteins requiring characterisation is a direct result of recent advances in genomics and proteomics, but protein aggregation is particular problem in the biotechnology industry, where aggregation is encountered throughout the lifetime of a therapeutic protein, including during refolding, purification, sterilization, shipping, and storage process. To ensure that it meets quality standards, the size, molecular weight and/or molecular weight distribution, and aggregate state must be accurately determined. Traditional analytical methods for determining molecular weight include size-exclusion chromatography (SEC), gel electrophoresis, analytical ultracentrifugation and time-of-flight mass spectrometry. These technologies are time-consuming (some take days), provide data based on relative standards, or cannot characterise very high molecular weight aggregates. Laser light-scattering (LS) detection coupled with SEC system have been used for over a decade to determine the size and molecular weight of bio-molecules such as proteins, peptides, polysaccharides, oligonucleotides, and antibodies, the method of choice being for molar mass determinations and the study of self-association and heterogeneous interaction under native, equilibrium conditions in solution. The purpose of the current review is to describe and discuss the capability of the SEC/LS system to determine absolute molecular weight of proteins and their complexes and the association state of the conjugate, either with itself or with protein receptor/ligands. For this, the "two or three detector" methods, each with its advantages and limitations, can be used to calculate the molecular weight of a simple protein or glycoprotein, and the stoichiometry of their complexes. Also, some alternative techniques for determining the molecular weight are discussed in this review. Applications of all these methodologies are described.

Effect of high shear rate on stability of proteins: kinetic study.

Size-exclusion chromatography (SEC) was used to monitor the time-course of protein degradation induced by high shear rates during the formulation and manufacture of controlled-release pharmaceutical dosage forms. SEC with multi-angle laser light-scattering (MALLS) detection was used to characterize the aggregation products, determining their absolute molecular weight. A stability-indicating method was developed and validated to obtain reliable drug degradation data. The results obtained according to the ICH guidelines confirm that the system and methods proposed are suitable for their intended use. The degradation kinetics are influenced by the type of protein and the effect of the shear rate on their stability. Reversible pseudo-first order degradation kinetics were observed for bovine beta-lactoglobulin, whereas for human (HSA) and bovine serum albumin (BSA), a monomer-dimer transition was observed, independently of the rate of shear. However, trimer formation was also observed for HSA, especially at high shear rates. The kinetic model may thus be described as a two-step process: a monomer-dimer, and dimer-trimer transition.

In-vitro release of fluoropyrimidines from PLGA film implants.

The release of two low-molecular weight water-soluble fluoropyrimidines, 5-fluorouracil and 5-fluorouridine, from implants of PLGA films was modulated by varying the area (diameter) and number of layers of film per implant. The aim was to achieve continuous release without burst effect for at least a month. The film implants were prepared by the solvent evaporation technique. Except with 5-fluorouracil films, the in-vitro release profiles were in all cases triphasic, indicating that release proceeds by a combination of diffusion and polymer erosion. The experimental data fit the equation resulting from the sum of two exponentials, one direct and the other inverse. 5-fluorouridine release from simple films presented a relatively minor burst effect (24-28%). In contrast, the delivery of both compounds from sandwich-type implants occurred continuously without a burst effect, and lasted for 17-20 days. During the first phase, both 3- and 5-mm sandwiches released 55% of the dose of 5-fluorouridine, at rate constants of 0.037+/-0.021 h(-1) (n = 3) and 0.009+/-0.003 h(-1) (n=3), respectively. In the second phase, release was gradual from both simple films (k2 = 0.011-0.015 h(-1)) and sandwiches (k2 = 0.018-0.058 h(-1)). According to the analysis-of-variance results, neither the area nor type of implant influenced the rate constants significantly. The release profiles of 5-fluorouracil from simple films showed a severe burst effect (64-71%). Release of 5-fluorouracil was gradual only from sandwiches, 5 mm in diameter, showing a lag time unobserved in the 3-mm sandwiches. In the second phase, release was gradual (k2 = 0.014+/-0.003 h(-1)) from 3-mm implants. However, the high variability in results for 5-mm implants prevents conclusions being drawn about the model parameters. Therefore, the sandwich-type film implants showed their utility for releasing water-soluble drugs for a prolonged time, without burst effect.