Relationship between Surface Properties and In Vitro Drug Release from a Compressed Matrix Containing an Amphiphilic Polymer Material

Functional in situ formed deep eutectic solvents improving mechanical properties of powders by enhancing interfacial interactions

As novel green solvents, deep eutectic solvent (DES) with distinct liquid properties has gained increasing interest in pharmaceutical fields. In this study, DES was firstly utilized for improving powder mechanical properties and tabletability of drugs, and the interfacial interaction mechanism was explored. Honokiol (HON), a natural bioactive compound, was used as model drug, and two novel HON-based DESs were synthesized with choline chloride (ChCl) and l-menthol (Men), respectively. The extensive non-covalent interactions were account for DES formation according to FTIR, ¹H NMR and DFT calculation. PLM, DSC and solid-liquid phase diagram revealed that DES successfully in situ formed in HON powders, and the introduction of trace amount DES (99:1 w/w for HON-ChCl, 98:2 w/w for HON-Men) significantly improve mechanical properties of HON. Surface energy analysis and molecular simulation revealed that the introduced DES promoted the formation of solid-liquid interfaces and generation of polar interactions, which increase interparticulate interactions, thus better tabletability. Compared to nonionic HON-Men DES, ionic HON-ChCl DES exhibited better improvement effect, since their more hydrogen-bonding interactions and higher viscosity promote stronger interfacial interactions and adhesion effect. The current study provides a brand-new green strategy for improving powder mechanical properties and fills in the blank of DES application in pharmaceutical industry.

Design and optimization of a novel herbosomal-loaded PEG-poloxamer topical formulation for the treatment of cold injuries: a quality-by-design approach

The spectrum of cold injuries ranges from frostnip, chilblains to severe frostbite. Cold injuries occur upon prolonged exposure to freezing temperature and are pathologically a combination of ice crystal formation in the tissue resulting in inflammation, thrombosis and ischemia in the extremities, often necessitating limb amputation in extreme cases due to tissue necrosis. Severe forms of frostbite are a cause of major concern to patients as well as the treating physician. Due to the lack of effective treatment modalities and paucity of research on prophylaxis and therapeutics of cold injuries, we developed a novel herbosomal-loaded PEG-poloxamer topical formulation (n-HPTF) employing quality-by-design (QBD) approach. Natural compounds exhibiting potent therapeutic potential for the management of cold injuries were incorporated in novel lipid vesicles (herbosomes) loaded in PEG-poloxamer polymers. The herbosomal formulation effectively creates an occlusion barrier that promotes epithelial regeneration, desmosome scale-up and angiogenesis and thus promotes rapid healing, indicating controlled release of herbosomes. Optimized novel herbosomes showed entrapment efficiency > 90% and < 300 nm mean particle size and in vitro drug permeation of about 2 µg/cm² followed Higuchi's release kinetics. Skin irritancy study on female Sprague-Dawley rats showed no edema or erythema. In vivo bio-efficacy study revealed significant efficacy (p < 0.05) when compared to the standard treatment groups. Graphical abstract presenting the designing and optimization of novel herbosomal-loaded PEG-poloxamer topical formulation (n-HPTF) and predictive model for the in vivo study of the developed n-HPTF on cold injury rat skin model.

Novel 3D-Printed Dressings of Chitosan-Vanillin-Modified Chitosan Blends Loaded with Fluticasone Propionate for Treatment of Atopic Dermatitis

In the present study, the blends of CS and Vanillin-CS derivative (VACS) were utilized for the preparation of printable inks for their application in three-dimensional (3D) printing procedures. Despite the synergic interaction between the blends, the addition of ι-carrageenan (iCR) as a thickening agent was mandatory. Their viscosity analysis was conducted for the evaluation of the optimum CS/VACS ratio. The shear thinning behavior along with the effect of the temperature on viscosity values were evident. Further characterization of the 3D-printed structures was conducted. The effect of the CS/VACS ratio was established through swelling and contact angle measurements. An increasing amount of VACS resulted in lower swelling ability along with higher hydrophobicity. Fluticasone propionate (FLU), a crystalline synthetic corticosteroid, was loaded into the CS/VACS samples. The drug was loaded in its amorphous state, and consequently, its in vitro release was significantly enhanced. An initial burst release, followed by a sustained release profile, was observed.

Nanocrystal-based gel of apremilast ameliorates imiquimod-induced psoriasis by suppressing inflammatory responses

Apremilast is 'difficult-to-deliver' in stratum corneum and viable layers (viable epidermis, dermis) owing to its modest lipophilicity and poor aqueous solubility, respectively. The objective of the present research was to develop apremilast nanocrystal-based gel for enhanced anti-psoriatic efficacy for the treatment of psoriasis. Nanosuspension was generated by wet media milling with a mean particle size of 200 nm. In-vivoefficacy of nanocrystal-based gels was evaluated in the imiquimod-induced psoriatic plaque model. Nanocrystal-based gel (1% and 3% w/w) improved phenotypic, histopathological features of psoriatic skin and attenuated splenic hypertrophy, psoriasis area severity scoring. Enzyme-linked immunosorbent assay was performed to evaluate levels of psoriatic biochemical markers indicating a significant decrease in the concentration of cytokines such as IL-23, IL-17A, IL-6 and TNF-α by nanocrystal-based gels (1% and 3% w/w) over disease induced group. Skin irritation study revealed that nanocrystal-based gel was significantly less irritating than the positive control. These results suggest that nanocrystal-based gel of apremilast can be an effective strategy for the management of psoriasis.

Application of machine learning to a material library for modeling of relationships between material properties and tablet properties

This study investigates the usefulness of machine learning for modeling complex relationships in a material library. We tested 81 types of active pharmaceutical ingredients (APIs) and their tablets to construct the library, which included the following variables: 20 types of API material properties, one type of process parameter (three levels of compression pressure), and two types of tablet properties (tensile strength (TS) and disintegration time (DT)). The machine learning algorithms boosted tree (BT) and random forest (RF) were applied to analysis of our material library to model the relationships between input variables (material properties and compression pressure) and output variables (TS and DT). The calculated BT and RF models achieved higher performance statistics compared with a conventional modeling method (i.e., partial least squares regression), and revealed the material properties that strongly influence TS and DT. For TS, true density, the tenth percentile of the cumulative percentage size distribution, loss on drying, and compression pressure were of high relative importance. For DT, total surface energy, water absorption rate, polar surface energy, and hygroscopicity had significant effects. Thus, we demonstrate that BT and RF can be used to model complex relationships and clarify important material properties in a material library.

Deaggregation and Crystallization Inhibition by Small Amount of Polymer Addition for a Co-Amorphous Curcumin-Magnolol System

Different from previously reported co-amorphous systems, a co-amorphous curcumin-magnolol (CUR-MAG CM) system, as compared with its crystalline counterparts, exhibited decreased dissolution due to its aggregation during dissolution. The main purpose of the present study is to deaggregate CUR-MAG CM to optimize drug dissolution and explore the deaggregation mechanism involved. Herein, a small amount of polymer (HPMC, HPC, and PVP K30) was co-formulated at 5% (w/w) with CUR-MAG CM as ternary co-amorphous systems. The polymer addition changed the surface properties of CUR-MAG CM including improved water wettability enhanced surface free energy, and hence exerted a deaggregating effect. As a result, the ternary co-amorphous systems showed faster and higher dissolution as compared with crystalline CUR/MAG and CUR-MAG CM. In addition, the nucleation and crystal growth of dissolved CUR and MAG molecules were significantly inhibited by the added polymer, maintaining a supersaturated concentration for a long time. Furthermore, polymer addition increased the T_g of CUR-MAG CM, potentially involving molecular interactions and inhibiting molecular mobility, resulting in enhanced physical stability under 25 °C/60% RH and 40 °C/75% RH conditions. Therefore, this study provides a promising strategy to optimize the dissolution and physical stability of co-amorphous systems by deaggregation and crystallization inhibition via adding small amounts of polymers.

Improvement in Solubility and Absorption of Nifedipine Using Solid Solution: Correlations between Surface Free Energy and Drug Dissolution

Ternary solid solutions composed of nifedipine (NDP), amino methacrylate copolymer (AMCP), and polysorbate (PS) 20, 60, or 65 were prepared using a solvent evaporation method. The dissolution profiles of NDP were used to study the effect of the addition of polysorbate based on hydrophilic properties. A solid solution of NDP and AMCP was recently developed; however, the dissolution of NDP was <70%. In the present study, polysorbate was added to improve the dissolution of the drug by altering its hydrophilicity. The suitable formulation contained NDP and AMCP at a ratio of 1:4 and polysorbate at a concentration of 0.1%, 0.3%, or 0.6%. Differential scanning calorimetry and powder X-ray diffraction were used to examine the solid solutions. No peak representing crystalline NDP was observed in any solid solution samples, suggesting that the drug was molecularly dispersed in AMCP. The NDP dissolution from NDP powder and solid solution without PS were 16.82% and 58.19%, respectively. The highest dissolution of NDP of approximately 95.25% was noted at 120 min for the formulation containing 0.6% PS20. Linear correlations were observed between the surface free energy and percentages of dissolved NDP (R² = 0.7115–0.9315). Cellular uptake across Caco-2 was selected to determine the drug permeability. The percentages of cellular uptake from the NDP powder, solid solution without and with PS20 were 0.25%, 3.60%, and 7.27%, respectively.

An Assessment of Surface Treatments for Adhesion of Polyimide Thin Films

Polyimide films are currently of great interest for the development of flexible electronics and sensors. In order to ensure a proper integration with other materials and PI itself, some sort of surface modification is required. In this work, microwave oxygen plasma, reactive ion etching oxygen plasma, combination of KOH and HCl solutions, and polyethylenimine solution were used as surface treatments of PI films. Treatments were compared to find the best method to promote the adhesion between two polyimide films. The first selection of the treatment conditions for each method was based on changes in the contact angle with deionized water. Afterward, further qualitative (scratch test) and a quantitative adhesion assessment (peel test) were performed. Both scratch test and peel strength indicated that oxygen plasma treatment using reactive ion etching equipment is the most promising approach for promoting the adhesion between polyimide films.

Multiple variable effects in the customisation of fused deposition modelling 3D-printed medicines: A design of experiments (DoE) approach

Fused deposition modelling (FDM) is the most explored three-dimensional (3D) printing technique in pharmaceutics. However, there is still a lack of knowledge about the factors influencing the properties of the printed forms. Here, the main and combined effects of the presence of a pore former (mannitol, 0% or 10%), the infill percentage (50% or 100%) and the drug percentage (5% or 10%) on the pharmaceutical properties of 3D-printed forms were evaluated by a design of experiments (DoE) approach. Poly(Ɛ-caprolactone) filaments were produced by hot-melt extrusion and dexamethasone was used as a hydrophobic model drug. The 2³ factorial design afforded eight formulations printed at 105 °C. The drug content ranged from 9.87 to 25.59 mg/unit, depending on the drug and infill percentages. The drug release profiles followed the Higuchi model. The infill percentage modulated the drug release rate, whereas the pore former had a combined effect on this parameter, depending on the drug and infill percentage levels. According to the DoE data, besides the changes in the infill percentage, the addition of a pore former can also tailor the drug release rate from 3D-printed solid forms. These findings may assist the development of personalised tumour implants by 3D printing.

Application of Aquasolv Lignin in ibuprofen-loaded pharmaceutical formulations obtained via direct compression and wet granulation

AS (Aquasolv) Lignin produced via Liquid Hot Water Pretreatment and Enzymatic Hydrolysis has shown potential as an active pharmaceutical ingredient and/or excipient in solid dosage forms. Moreover, lignin is safe to consume and presents antioxidant and antidiabetic capacity, properties that can add to solid dosage forms in pharmaceuticals. This work aimed to evaluate the performance of tablets produced via direct compression and wet granulation when lignin is used in combination with commercial excipients. In order to find optimal tablet performance, different lignin formulations were assessed, and the concentrations were given by extreme vertices mixture design (13 formulations). The blends were composed of AS Lignin, Microcrystalline Cellulose, and Lactose monohydrate and the optimized blend was found to be 14.53 w/w% of disintegrant, 26.57 w/w% of binder and 58.9 w/w% of AS lignin. This proportion was further used to evaluate the performance of lignin-based tablets in drug release, using Ibuprofen as a drug model (50 w/w% and 70 w/w%) and for comparison of direct compression with wet granulation. Direct compressed tablets resulted in higher drug dissolution rates when compared with wet granulation, nevertheless; both tableting techniques showed promising results for lignin. More than 5 formulations tested in this work are compliant with International Pharmacopoeia regulations for solid dosage pharmaceutical forms, thus AS Lignin shows potential to be used as an excipient in pharmaceutical formulations. INDUSTRIAL RELEVANCE: Industrially, AS Lignin appears as promising excipient in the pharmaceutical technologies as well as boost in the biorefining technologies in the following years. Lignin produced is free of sulfur, can be labelled as clean and environmentally-friendly and in this study, was proven this non-cytotoxic AS lignin can be used for excipients and drug carriers. The findings in this paper showed the use of product formulation for life science purposes, thus stressing one of possibilities for lignin valorization in biorefineries.

Development of Antioxidant-Loaded Nanoliposomes Employing Lecithins with Different Purity Grades

This work focused on comparing the ability of lecithins with two purity grades regarding their performance in the development of nanoliposomes, as well as their ability to contain and release polar (trans-aconitic acid) and non-polar (quercetin) antioxidant compounds. First, the chemical characterization of both lecithins was carried out through infrared spectroscopy (FTIR), electrospray ionization mass spectrometry (ESI/MS), and modulated differential scanning calorimetry (mDSC). Second, nanoliposomes were prepared by the ethanol injection method and characterized by means of particle size, polydispersity, and zeta potential measurements. Third, the encapsulation efficiency and in vitro release profiles of antioxidants were evaluated. Finally, the antioxidant effect of quercetin and trans aconitic acid in the presence and absence of nanoliposomes was assessed through the oxygen radical absorbance capacity (ORAC) assay. The results showed that, although there are differences in the chemical composition between the two lecithins, these allow the development of nanoliposomes with very similar physicochemical features. Likewise, nanoliposomes elaborated with low purity grade lecithins favored the encapsulation and release of trans-aconitic acid (TAA), while the nanoliposomes made with high purity lecithins favored the encapsulation of quercetin (QCT) and modified its release. Regarding the antioxidant effect, the vehiculization of TAA and QCT in nanoliposomes led to an increase in the antioxidant capability, where QCT showed a sustained effect over time and TAA exhibited a rapidly decaying effect. Likewise, liposomal systems were also found to have a slight antioxidant effect.

Preparation and study of two kinds of ophthalmic nano-preparations of everolimus

Objective: To prepare everolimus nanoformulations and increase their solubility to suit their application in the eye. Methods: The everolimus micelles was prepared by thin film dispersion method using Tween-80 (P80) and polyoxyethylene stearate (P40S) as carriers. In addition, the everolimus nanosuspension was prepared by injection method using poloxamer 407 (P407), hydroxypropyl methylcellulose (HPMC) and polyvinyl alcohol (PVA) as stabilizers. It was characterized in terms of particle size, PDI and encapsulation efficiency or drug loading. The in vitro release and in vitro rabbit scleral permeability characteristics were investigated, and the pharmacokinetics of anterior chamber drug in rabbit eyes were studied. Results: The average particle size of the micelles was (8.74 ± 0.21) nm, the encapsulation efficiency and drug loading were (90.12 ± 1.18)% and (2.14 ± 0.028)%, while the average particle size of the nanosuspension was (156.47 ± 1.10) nm, and the drug loading was (16.51 ± 0.21)%, respectively. Both in vitro release and rabbit scleral permeation models were consistent with the Higuchi equation. The pharmacokinetic experiments of aqueous humor showed that area under the curve of everolimus nanosuspension was about 3 times higher than that of micelles. Micelles could be achieved in the eye and maintained for a long time. Conclusion: The preparation of everolimus micelles or nanosuspension for eye are suitable for ocular administration and expected to be new dosage form for corneal transplantation immunological rejection or other ocular disease.

Synthesis, Characterisation and Biological Evaluation of Ampicillin-Chitosan-Polyanion Nanoparticles Produced by Ionic Gelation and Polyelectrolyte Complexation Assisted by High-Intensity Sonication

Recently, one of the promising strategies to fight sensitive and resistant bacteria, and decrease the morbidity and mortality rates due to non-nosocomial infections, is to use antibiotic-loaded nanoparticles. In this study, ampicillin-loaded chitosan-polyanion nanoparticles were produced through the techniques of ionic gelation and polyelectrolyte complexation assisted by high-intensity sonication, using several crosslinking agents, including phytic acid (non-polymeric polyanion), sodium and potassium salts of poly(maleic acid-alt-ethylene) and poly(maleic acid-alt-octadecene) (polymeric polyanions). These nanoparticles were analysed and characterised in terms of particle size, polydispersity index, zeta potential and encapsulation efficiency. The stability of these nanosystems was carried out at temperatures of 4 and 40 °C, and the antimicrobial effect was determined by the broth microdilution method using sensitive and resistant Staphylococcus aureus strains. The results reveal that most of the nanosystems have sizes <220 nm, positive zeta potential values and a monodisperse population, except for the nanoparticles crosslinked with PAM-18 polyanions. The nanometric systems exhibited adequate stability preventing aggregation and revealed a two-fold increase in antimicrobial activity when compared with free ampicillin. This study demonstrates the potential application of synthesised nanoparticles in the field of medicine, especially for treating infections caused by pathogenic S. aureus strains.

Relationship between Degree of Polymeric Ionisation and Hydrolytic Degradation of Eudragit® E Polymers under Extreme Acid Conditions

The commercial copolymers Eudragit^® E 100 and Eudragit^® PO are widely used materials in the pharmaceutical field as coating systems. Such materials derived from amino-methacrylate groups under acidulated conditions may acquire an ionisable fraction or undergo hydrolytic degradation of the polymeric structure. This work focused on establishing the chemical, physical, and surface changes of two reprocessed polymeric materials, here named as EuCl-E-100 and EuCl-E-PO, which were obtained from the commercial Eudragit^® E 100 and Eudragit^® E PO, respectively. The commercial materials were exposed to extreme acid conditions, where the polymers were solubilised and subsequently dried by the refractance window method. The materials obtained were chemically characterised by potentiometric titration, nuclear magnetic resonance spectroscopy (¹H NMR and ¹³C NMR) in one and two dimensions (COSY, HSQC, and HMBC), infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry. Changes in the physical properties of the materials were evaluated through studies of flowability, compactability, and their ability to gain and lose humidity. Surface thermodynamic studies were carried out through contact angle measurements using the sessile drop method. The results showed that the processed polymeric materials acquired a substantial degree of ionisation without undergoing hydrolysis of the esterified groups. Furthermore, such changes improved the flow characteristics of the material and the solubility in aqueous media at pH > 5, while also maintaining the hydrophobicity degree of the polymeric surface.

Effect of the Surface Hydrophobicity Degree on the In Vitro Release of Polar and Non-Polar Drugs from Polyelectrolyte Matrix Tablets

This work is the continuation of a series of studies focused on establishing the relationship between the surface thermodynamic properties of polyelectrolyte matrix tablets and drug release mechanisms. In this case, two model drugs with different polarity features, such as carbamazepine (non-polar) and metoprolol succinate (polar) were used in combination with polymeric material hydroxypropyl-methyl cellulose (HPMC) and two polyelectrolytes derived from maleic anhydride corresponding to the sodium salts of poly(maleic acid-alt-ethylene) and poly(maleic acid-alt-octadecene) named PAM-0Na and PAM-18Na, respectively. The polymers were obtained and characterized as reported previously. Surface studies were performed by the sessile drop method, whilst the surface free energy was determined through Owens, Wendt, Rable and Kaeble (OWRK) semi-empirical model. By contrast, the drug release studies were performed by in vitro dissolution tests, where data were analyzed through dissolution efficiency. The results showed that, depending on the drug polarity, type and polymer proportion, surface properties and drug release processes are significantly affected.

Franz Diffusion Cell Approach for Pre-Formulation Characterisation of Ketoprofen Semi-Solid Dosage Forms

This study aimed to evaluate and compare, using the methodology of Franz diffusion cells, the ketoprofen (KTP) releasing profiles of two formulations: A gel and a conventional suspension. The second aim was to show that this methodology might be easily applied for the development of semi-solid prototypes and claim proof in pre-formulation stages. Drug release analysis was carried out under physiological conditions (pH: 5.6 to 7.4; ionic strength 0.15 M; at 37 °C) for 24 h. Three independent vertical Franz cells were used with a nominal volume of the acceptor compartment of 125 mL and a diffusion area of 2.5 cm². Additionally, two different membranes were evaluated: A generic type (regenerated cellulose) and a transdermal simulation type (Strat-M®). The KTP permeation profiles demonstrated that depending on the membrane type and the vehicle used, the permeation is strongly affected. High permeation efficiencies were obtained for the gel formulation, and the opposite effect was observed for the suspension formulation. Moreover, the permeation studies using Strat-M membranes represent a reproducible methodology, which is easy to implement for pre-formulation stage or performance evaluation of semi-solid pharmaceutical products for topical or transdermal administration.

Natural gum-type biopolymers as potential modified nonpolar drug release systems

In this work, the relationship between surface properties and drug release mechanism from binary composition tablets formed by quetiapine fumarate and biopolymer materials was studied. The biopolymers correspond to xanthan and tragacanth gums, which are projected as modified drug release systems. The surface studies were carried out by the sessile drop method, while the surface free energy (SFE) was determinate through Young-Dupree and OWRK semi-empirical models. On the other hand, the drug release studies were performed by in vitro dissolution tests, where the data were analyzed through kinetic models of zero order, first order, Higuchi, and Korsmeyer-Peppas. The results showed that depending on the type and the proportion of biopolymer, surface properties, and the drug release processes are significantly affected, wherein tragacanth gum present a usual erosion mechanism, while xanthan gum describes a swelling mechanism that controls the release of the drug.

Relationship between the Polymeric Ionization Degree and Powder and Surface Properties in Materials Derived from Poly(maleic anhydride-alt-octadecene)

Polymeric materials derived from poly(maleic anhydride-alt-octadecene)-here referred as PAM-18-have shown interesting properties that make them potential pharmaceutical excipients. In this work, eight polymers derived from PAM-18 were obtained using NaOH and KOH at 1:1; 1:0.75, 1:0.5, and 1:0.25 molar ratios. The resulting products were labeled as PAM-18Na and PAM-18K, respectively. Each polymer was purified by ultrafiltration/lyophilization, and the ionization degree was determined by potentiometric studies, which was related to the zeta potential. The structural characterization was performed using the Fourier transform infrared (FT-IR) espectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) techniques. The physical characterization was carried out by SEM, particle analysis, and humidity loss and gain studies; the surface studies were performed by the sessile drop method. PAM-18Na had ionization degrees of 95%, 63%, 39% and 22%, whereas those for PAM-18K were 99%, 52%, 35% and 20%, respectively. The results also showed that for higher inorganic base amounts used, the polymeric materials obtained possess high ionization degrees, which could form polymeric solutions or hetero-dispersed systems. Likewise, it was observed that for higher proportions of carboxylate groups in the polymeric structure, the capability to retain water is increased and, only can be eliminated by drying at temperatures greater than 160 °C. On the other hand, the modification of PAM-18 to its ionized forms led to the formation of powder materials with low flowability and surfaces that ranged from very hydrophobic to slightly wettable.

Relationship between Surface Properties and In Vitro Drug Release from Compressed Matrix Containing Polymeric Materials with Different Hydrophobicity Degrees

This work is the continuation of a study focused on establishing relations between surface thermodynamic properties and in vitro release mechanisms using a model drug (ampicillin trihydrate), besides analyzing the granulometric properties of new polymeric materials and thus establishing the potential to be used in the pharmaceutical field as modified delivery excipients. To do this, we used copolymeric materials derived from maleic anhydride with decreasing polarity corresponding to poly(isobutylene-alt-maleic acid) (hydrophilic), sodium salt of poly(maleic acid-alt-octadecene) (amphiphilic), poly(maleic anhydride-alt-octadecene) (hydrophobic) and the reference polymer hydroxyl-propyl-methyl-cellulose (HPMC). Each material alone and in blends underwent spectroscopic characterization by FTIR, thermal characterization by DSC and granulometric characterization using flow and compaction tests. Each tablet was prepared at different polymer ratios of 0%, 10%, 20%, 30% and 40%, and the surface properties were determined, including the roughness by micro-visualization, contact angle and water absorption rate by the sessile drop method and obtaining Wadh and surface free energy (SFE) using the semi-empirical models of Young-Dupré and  Owens-Wendt-Rabel-Käelbe (OWRK), respectively. Dissolution profiles were determined simulating physiological conditions in vitro, where the kinetic models of order-zero, order-one, Higuchi and Korsmeyer-Peppas were evaluated. The results showed a strong relationship between the proportion and nature of the polymer to the surface thermodynamic properties and kinetic release mechanism.