Dapsone (DAP) is a synthetic sulfone drug with bacteriostatic activity, mainly against Mycobacterium leprae. In this study we have investigated the interactions of DAP with cyclodextrins, 2-hydroxypropyl-b-cyclodextrin (HPbCD) and b-cyclodextrin (bCD), in the presence and absence of water-soluble polymers, in order to improve its solubility and bioavailability. Solid systems DAP/HPbCD and DAP/bCD, in the presence or absence of polyvinylpyrrolidone (PVP K30) or hydroxypropyl methylcellulose (HPMC), were prepared. The binary and ternary systems were evaluated and characterized by SEM, DSC, XRD and NMR analysis as well as phase solubility assays, in order to investigate the interactions between DAP and the excipients in aqueous solution. This study revealed that inclusion complexes of DAP and cyclodextrins (HPbCD and bCD) can be produced in order to improve DAP solubility and bioavailability in the presence or absence of polymers (PVP K30 and HPMC). The more stable inclusion complex was obtained with HPbCD, and consequently HPbCD was more efficient in improving DAP solubility than bCD, and the addition of polymers had no influence on DAP solubility or on the stability of the DAP/CDs complexes.

Transdermal applications of drugs present many advantages in terms of absorption, however this is not easily obtained through the transdermal route. The principle barrier is the stratum corneum and one of the strategies that have been found to promote cutaneous drug penetration is through the use of absorption enhancers. Many substances have been identified as absorption enhancers. Although the list of substances that promote absorption is growing, in most cases, there is a direct correlation between the effects of absorption enhancers and their skintoxicity. The use of these substances depends therefore on studies which focus on local and systemic toxicity, as well as action mechanisms.

A simple spectrophotometric method is proposed for the determination of cefaclor. The method involves alkaline hydrolysis of the drug in ammonia buffer solution at pH 10 to yield diketopiperazine-2,5-dione derivative and subsequent measurement at 340 nm. Beer's law is obeyed in the concentration range 1.8 - 55 mg/mL. The proposed method was successfully applied to the determination of cefaclor in pharmaceutical formulations

Albendazole and fenbendazole are imidazole derivatives that exhibit broad spectrum activity against parasites, but the low solubility of these drugs considerably reduces their effectiveness. Complexation of albendazole and fenbendazole with cyclodextrins (β-cyclodextrin and hydroxypropyl-β-cyclodextrin) in both water and an aqueous solution of polyvinylpyrrolidone (PVP-k30) was studied to determine if it could increase the solubility and dissolution rate of the drugs. In an aqueous solution, β-cyclodextrin increased the solubility of albendazole from 0.4188 to ∼93.47 µg mL-1 (223×), and of fenbendazole from 0.1054 to 45.56 µg mL-1 (432×); hydroxypropyl-β-cyclodextrin, on the other hand, increased solubility to ∼443.06 µg mL-1 (1058×) for albendazole and ∼159.36 μg mL-1 (1512×) for fenbendazole. The combination of hydroxypropyl-β-cyclodextrin and polyvinylpyrrolidone enabled a solubility increase of 1412× (∼591.22 µg mL-1) for albendazole and 1373× (∼144.66 µg mL-1) for fenbendazole. The dissolution rate of the drugs was significantly increased in binary and ternary systems, with hydroxypropyl-β-cyclodextrin proving to be more effective. The presence of the water-soluble PVP-k30 increased the dissolution rate and amorphization of the complexes. Analysis of the changes in displacement and the profile of the cyclodextrin bands in the 1 H NMR spectra revealed a molecular interaction and pointed to an effective complexation in the drug/cyclodextrin systems. Monomeric forms and nanoclusters of cyclodextrins were observed in the drug/cyclodextrin systems, suggesting that the increase in solubility of the drugs in the presence of cyclodextrins should not be attributed only to the formation of inclusion complexes, but also to the formation of cyclodextrin aggregates.

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The pharmaceutical industry is constantly evolving. The harmonization of production standards, with the aim of guaranteeing efficacy, safety and quality of medicines, is one of the greatest challenges. The concept of "Quality by design" (QbD) proposes a systematic approach, based on scientific knowledge and risk management associated with the manufacturing process. In this approach, quality is inversely proportional to variability. The implementation of the QbD concept is a promising tool for pharmaceutical production, since it allows the production of medicines by means of risk prediction, increasing the possibility of generating products with efficiency, safety and quality assured, together with the reduction of costs. The implementation of this concept requires not only new technologies, but the change in the concept of quality.Keywords: pharmaceutical processes; quality by design; process analytical techniques. RESUMOO setor farmacêutico está em constante evolução. A harmonização de normas de produção, com o intuído de garantir eficácia, segurança e qualidade dos medicamentos, consiste em um dos maiores desafios. O conceito "qualidade baseada no projeto" (Quality by design, QbD) propõe uma abordagem sistemática, fundamentada no conhecimento científico e no gerenciamento do risco associado ao processo de fabricação. Nesta abordagem, qualidade é inversamente proporcional a variabilidade. A implementação do conceito de QbD constitui uma ferramenta promissora para a produção farmacêutica pois permite a produção de medicamentos por meio da previsão de riscos, ampliando a possibilidade de gerar produtos com eficácia, segurança e qualidade assegurados, aliado a redução de custos. A implementação deste conceito exige não somente novas tecnologias, mas a mudança no conceito de qualidade.Palavras-chave: processos farmacêuticos; qualidade baseada no projeto; técnicas analíticas de processo INTRODUÇÃO A produção de medicamentos inclui uma série de processos farmacêuticos, caracterizados por uma sequência de operações unitárias, que realizam transformações químicas ou físicas em matérias-primas, com o fim de gerar produtos com eficácia, segurança e qualidade assegurados (1). Estabelecidos durante o desenvolvimento dos produtos, os processos farmacêuticos devem ser submetidos a aprovação por órgãos regulatórios para concessão de registro de comercialização, o qual assegura que a empresa comprovou ter condições de fornecer produtos de qualidade desejada de forma consistente, conforme as exigências regulatórias (2,3).Apesar do rigor das agências regulatórias na elaboração de normas e guias para a produção farmacêutica, estes requerimentos apresentam limitações, e falhas nos processos farmacêuticos são comumente observadas, o

Albendazole (ABZ), a benzimidazole widely used to control gastrointestinal parasites, is poorly soluble in water, resulting in variable and incomplete bioavailability. This has favored the appearance ABZ-resistant nematodes and, consequently, an increase in its clinical ineffectiveness. Among the pharmaceutical techniques developed to increase drug efficacy, cyclodextrins (CDs) and other polymers have been extensively used with water-insoluble pharmaceutical drugs to increase their solubility and availability. Our objective was to prepare ABZ formulations, including β-cyclodextrin (βCD) or hydroxypropyl-β-cyclodextrin (HPβCD), associated or not to the water-soluble polymer polyvinylpyrrolidone (PVP). These formulations had their solubility and anthelmintic effect both evaluated in vitro. Also, their anthelmintic efficacy was evaluated in lambs naturally infected with gastrointestinal nematodes (GIN) through the fecal egg count (FEC) reduction test. In vitro, the complex ABZ/HPβCD had higher solubility than ABZ/βCD. The addition of PVP to the complexes increased solubility and dissolution rates more effectively for ABZ/HPβCD than for ABZ/βCD. In vivo, 48 lambs naturally infected with GIN were divided into six experimental groups: control, ABZ, ABZ/βCD, ABZ/βCD-PVP, ABZ/HPβCD, and ABZ/HPβCD-PVP. Each treated animal received 10 mg/kg of body weight (based on the ABZ dose) for three consecutive days. After 10 days of the last administered dose, treatment efficacy was calculated. The efficacy values were as follows: ABZ (70.33%), ABZ/βCD (85.33%), ABZ/βCD-PVP (82.86%), ABZ/HPβCD (78.37%), and ABZ/HPβCD-PVP (43.79%). In vitro, ABZ/HPβCD and ABZ/HPβCD-PVP had high solubility and dissolution rates. In vivo, although the efficacies of ABZ/βCD, ABZ/βCD-PVP, and ABZ/HPβCD increased slightly when compared to pure ABZ, this increase was not significant (P > 0.05).

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