Osvaldo de Freitas

A poloxamer/chitosan in situ forming gel with prolonged retention time for ocular delivery.

The aim of the present work was to obtain an ophthalmic delivery system with improved mechanical and mucoadhesive properties that could provide prolonged retention time for the treatment of ocular diseases. For this, an in situ forming gel comprised of the combination of a thermosetting polymer, poly (ethylene oxide)-poly (propylene oxide)-poly (ethylene oxide) (PEO-PPO-PEO, poloxamer), with a mucoadhesive agent (chitosan) was developed. Different polymer ratios were evaluated by oscillatory rheology, texture and mucoadhesive profiles. Scintigraphy studies in humans were conduced to verify the retention time of the formulations developed. The results showed that chitosan improves the mechanical strength and texture properties of poloxamer formulations and also confers mucoadhesive properties in a concentration-dependent manner. After a 10-min instillation of the poloxamer/chitosan 16:1 formulation in human eyes, 50-60% of the gel was still in contact with the cornea surface, which represents a fourfold increased retention in comparison with a conventional solution. Therefore, the developed formulation presented adequate mechanical and sensorial properties and remained in contact with the eye surface for a prolonged time. In conclusion, the in situ forming gel comprised of poloxamer/chitosan is a promising tool for the topical treatment of ocular diseases.

Rheological, mechanical and mucoadhesive properties of thermoresponsive, bioadhesive binary mixtures composed of poloxamer 407 and carbopol 974P designed as platforms for implantable drug delivery systems for use in the oral cavity

This study described the formulation and characterisation of the viscoelastic, mechanical and mucoadhesive properties of thermoresponsive, binary polymeric systems composed of poloxamer (P407) and poly(acrylic acid, C974P) that were designed for use as a drug delivery platform within the oral cavity. Monopolymeric and binary polymeric formulations were prepared containing 10, 15 and 20% (w/w) poloxamer (407) and 0.10-0.25% (w/w) poly(acrylic acid, 934P). The flow rheological and viscoelastic properties of the formulations were determined using controlled stress and oscillatory rheometry, respectively, the latter as a function of temperature. The mechanical and mucoadhesive properties (namely the force required to break the bond between the formulation and a pre-hydrated mucin disc) were determined using compression and tensile analysis, respectively. Binary systems composed of 10% (w/w) P407 and C934P were elastoviscous, were easily deformed under stress and did not exhibit mucoadhesion. Formulations containing 15 or 20% (w/w) Pluronic P407 and C934P exhibited a sol-gel temperature T(sol/gel), were viscoelastic and offered high elasticity and resistance to deformation at 37 degrees C. Conversely these formulations were elastoviscous and easily deformed at temperatures below the sol-gel transition temperature. The sol-gel transition temperatures of systems containing 15% (w/w) P407 were unaffected by the presence of C934P; however, increasing the concentration of C934P decreased the T(sol/gel) in formulations containing 20% (w/w) P407. Rheological synergy between P407 and C934P at 37 degrees C was observed and was accredited to secondary interactions between these polymers, in addition to hydrophobic interactions between P407 micelles. Importantly, formulations composed of 20% (w/w) P407 and C934P exhibited pronounced mucoadhesive properties. The ease of administration (below the T(sol/gel)) in conjunction with the viscoelastic (notably high elasticity) and mucoadhesive properties (at body temperature) render the formulations composed of 20% (w/w) P407 and C934P as potentially useful platforms for mucoadhesive, controlled topical drug delivery within the oral cavity.

Oral bioadhesive drug delivery systems.

The oral mucosal cavity is a feasible, safe, and very attractive site for drug delivery with good acceptance by users. The mucosa is relatively permeable and robust, shows short recovery times after stress or damage, is tolerant to potential allergens, and has a rich blood supply. Moreover, oral mucosal drug delivery bypasses the first-pass effect and avoids presystemic elimination in the gastrointestinal tract. Bioadhesive systems provide intimate contact between a dosage form and the absorbing tissue, which may result in high concentration in a local area and hence high drug flux through the absorbing tissue. The efficacy of oral bioadhesive drug delivery systems is affected by the biological environment and the properties of the polymer and the drug. In the present paper, we review systematically some relevant citations regarding the environment, strategies for oral drug delivery and evaluation, and utilization of the main polymers.

Stability of microencapsulated B. lactis (BI 01) and L. acidophilus (LAC 4) by complex coacervation followed by spray drying

Microcapsules containing Bifidobacterium lactis (BI 01) and Lactobacillus acidophilus (LAC 4) were produced by complex coacervation using a casein/pectin complex as the wall material, followed by spray drying. The aim of this study was to evaluate the resistance of these microorganisms when submitted to the spray drying process, a shelf-life of 120 days at 7–37°C and the in vitro tolerance after being submitted to acid pH (pH 1.0 and 3.0) solutions besides morphology of microcapsules. Microencapsulated microorganisms were shown to be more resistant to acid conditions than free ones. Microencapsulated L. acidophilus maintained its viability for a longer storage period at both temperatures. The microcapsules presented a spherical shape with no fissures. The process used and the wall material were efficient in protecting the microorganisms under study against the spray drying process and simulated gastric juice; however, microencapsulated B. lactis lost its viability before the end of the storage time.

Enhancing and sustaining the topical ocular delivery of fluconazole using chitosan solution and poloxamer/chitosan in situ forming gel.

Fungal keratitis is a serious disease that can lead to loss of vision. Unfortunately, current therapeutic options often result in poor bioavailability of antifungal agents due to protective mechanisms of the eye. The aim of this work was to evaluate the potential of a chitosan solution as well as an in situ gel-forming system comprised of poloxamer/chitosan as vehicles for enhanced corneal permeation and sustained release of fluconazole (FLU). For this, in vitro release and ex vivo corneal permeation experiments were carried out as a function of chitosan concentration from formulation containing the chitosan alone and combined with the thermosensitive polymer, poloxamer. Microdialysis was employed in a rabbit model to evaluate the in vivo performance of the formulations. The in vitro release studies showed the sustained release of FLU from the poloxamer/chitosan formulation. Ex vivo permeation studies across porcine cornea demonstrated that the formulations studied have a permeation-enhancing effect that is independent of chitosan concentration in the range from 0.5 to 1.5% w/w. The chitosan solutions alone showed the greatest ex vivo drug permeation; however, the poloxamer/chitosan formulation presented similar in vivo performance than the chitosan solution at 1.0%; both formulations showed sustained release and about 3.5-fold greater total amount of FLU permeated when compared to simple aqueous solutions of the drug. In conclusion, it was demonstrated that both the in situ gelling formulation evaluated and the chitosan solution are viable alternatives to enhance ocular bioavailability in the treatment of fungal keratitis.

A evolução da Atenção Farmacêutica e a perspectiva para o Brasil

The Pharmaceutical Care, recent practice of the pharmaceutical activity, prioritizes the orientation and the pharmacotherapeutic follow up, besides direct relation among the pharmacist and the medicines user. In most developed countries the Pharmaceutical Care is already a reality and has demonstrated efficacy in the reduction of aggravation in the chronical diseases and in the cost of the health system. In Brazil, this activity is still incipient due to the difficulty of access to the medicines by the users of the Health System, absence of pharmacists in the Basic Units of Health and absence of scientific documentation that may demonstrate to the managers of the public and private system of Health that the implementation of Pharmaceutical Care represent investment and not cost. However, for being a new activity of the pharmacist, it is demanding that the pharmaceutical education institutions promote the necessary adaptations, providing the formal knowledge for the practice of this activity. This paper discuss the Pharmaceutical Care in countries that present more evolution in your desenvelopment according with MedLine/Pubmed (www.ncbi.nlm.nih.gov/PubMed). This article compared the difficulties of the Brazil and others countries for the implantation of Pharmaceutical Care and the prospect for the future.

Development of a colorimetric system for evaluation of the masticatory efficiency

The stomatognathic system is responsible for complex vital functions such as chewing, deglutition, respiration and phonation. Food breakdown is one of the masticatory functions, which enables reducing the attrition against the oral soft tissues and increasing the surface contact of food particles with digestive secretions, thus leading to satisfactory and rapid physiological processes. The methods of evaluation the masticatory efficiency are restricted to electromyography, sieving and clinical observation. However, the validity of these methods has been questioned due to the complexity of the procedures, variances in the material used and inaccuracy of methodologies. This study presents a new method in which a capsule of a synthetic material using fuchsin-containing granules was devised. Such capsules were submitted to several laboratory tests in order to determine their resistance and absorbency. Ten calibrated individuals were instructed to chew the capsules. Masticatory efficiency was determined by analyzing fuchsin concentration in a solution obtained from chewed granules measuring the absorbance at 546 nm. The method was found to be fast, simple, reproducible, inexpensive and efficient and can be used as a complementary evaluation of the masticatory efficiency in different situations.

Perfil da assistência farmacêutica na atenção primária do Sistema Único de Saúde

This paper presents a review and analysis of Pharmacist Care as an integrated part of the Primary Health Care System, in which quality use of medicines is directly related to quality health service and to elements for its evaluation. In our country the Basic Health Units represent the main entrance to the public health care system. The pharmaceutical services however are still linked to the care model centered in medical consultation and emergency care, with the pharmacy just satisfying their needs. Provide orientation to the users of a Basic Unit pharmacy is almost impossible because nearly all sore spots of the health system end up at the pharmacy as the final step in the care process. The solution of the problem will not be easy if the present structure of the service is maintained. Great part of the pressure resulting from the demand does not depend on the health service itself but on inclusive social policies with direct impact on the health conditions of the population. Rational use of medicines from the prescriber to the user is fundamental in this specific environment.

The Pharmaceutical care of patients with type 2 diabetes mellitus

Objective To evaluate the efficiency of pharmaceutical care on the control of clinical parameters, such as fasting glycaemia and glycosylated haemoglobin in patients with Type 2 Diabetes mellitus. Setting This study was conducted at the Training and Community Health Centre of the College of Medicine of Ribeirao Preto, University of Sao Paulo, Brazil. Methods A prospective and experimental study was conducted with 71 participants divided in two groups: (i) pharmaceutical care group (n=40), and (ii) the control group (n=31). The distribution of patients within these groups was made casually, and the patients were monitored for 12 months. Main outcome measure: Values for fasting glycaemia and glycosylated haemoglobin were collected. Results Mean values of fasting glycaemia in the pharmaceutical care group were significantly reduced whilst a small reduction was detected in the control group at the same time. A significant reduction in the levels of glycosylated haemoglobin was detected in patients in the pharmaceutical care group, and an average increase was observed in the control group. Furthermore, the follow-up of the intervention group by a pharmacist contributed to the resolution of 62.7% of 142 drug therapy problems identified. Conclusion In Brazil, the information provided by a pharmacist to patients with Type 2 Diabetes mellitus increases compliance to treatment, solving or reducing the Drug Therapy Problem and, consequently, improving glycaemic control.

Economic evaluation of outpatients with type 2 diabetes mellitus assisted by a pharmaceutical care service

OBJECTIVE To analyze the costs related to visits and drug prescription in outpatients with type 2 diabetes mellitus assisted by a pharmaceutical care service. SUBJECTS AND METHODS A prospective and experimental study was carried out. Seventy one patients were divided into two groups: control and pharmaceutical care. Patients in the pharmaceutical care group were followed up monthly by a single clinical pharmacist. RESULTS The pharmaceutical care group had a statistically significant reduction in costs of metformin and emergency department visits, and increased costs with their family physicians. On the other hand, the control group had a statistically significant increase of 21.3% in the general costs of treatment and visits. CONCLUSION The pharmaceutical care group maintained the same costs related to drugs and visits, while the control group showed a significant increase in general costs.