مقالات رزومه دکتر رضا عنایتی فرد

Background and

Psoriasis is an autoimmune inflammatory disease with major skin involvement. Calcipotriol as a vitamin-D analogue is one of the common drugs for topical treatment of psoriasis. Local drug delivery, due to higher concentration of drug at the sites of inflammation, is more effective and causes fewer systemic side effects. Limited skin penetration and durability of common topical formulations reduce the efficacy of treatment. In this study, we aimed to investigate the effect of solid lipid nanoparticles loaded with calcipotriol on local drug delivery.

In the present study, which is an interventional in vivo study, Solid Lipid Nanoparticle (SLN) was prepared by melting method and mixed with semi-solid base (cream). Then the effectiveness of the final formulation was investigated on the psoriasis model induced by imiquimod 5% in BALB/c mice. Three groups were included in this investigation: negative control (no treatment), positive control (conventional calcipotriol cream), and SLN (SLN cream with calcipotriol).

The results of the present study showed that, the SLN cream significantly reduced inflammatory scores compared to the other two groups on day five (P<0.0001). In addition, drug loading into SLN significantly increased the rate of healing and reduced inflammation.

This study showed that calcipotriol loading with SLN can improve the quality and the rate of treatment of skin lesions caused by psoriasis.

Buxus hyrcana Pojark. has been traditionally used for the treatment of skin disorders including wound injuries and recent studies have shown the therapeutic potential of some Buxus species in healing skin wounds. In this study, the effect of an ointment containing methanolic extract of B. hyrcana leaves was evaluated on the full-thickness wound healing in a rat model.

The full-thickness wound was made with a scalpel on the dorsum cervical area of 32 Wistar rats (weighing 250-300 g). The animals were randomly divided into four groups: I; control, II; ointment base (eucerin), III; 1 % phenytoin cream, and IV; 5 % B. hyrcana methanolic extract ointment. For histopathological assessment, wound criteria were evaluated on the 12th day of treatment according to the Abramov score method. The collagen fiber deposition in the skin tissue was determined using Masson’s trichrome staining. The spectrophotometric analysis was performed to evaluate the total phenol and total flavonoid content of the extract.

Based on macroscopic observations, herbal ointment increased wound closure in the treatment group compared to the control group. In this way, the collagen deposition, epidermal and keratin formation, neovascularization, and fibroblast maturation increased significantly (P<0.05) with the herbal ointment, the same as the phenytoin group. The extract did not show any antimicrobial effect using the disc agar diffusion method.

The observed wound-healing effect of B. hyrcana seems to be mainly due to the presence of flavonoid compounds in the plant extract.

Background and

Oral route is the most frequently used route for drug administration and tablets are the most popular oral drug forms. The study of drug-excepient compatibility is an important process in development of a stable solid dosage form. Incompatibility between drugs and excipients can alter the stability and bioavailability of drugs, thereby affecting its safety and/or efficacy. In this study, the effects of formulation ingredients under aging and environmental factors on physical properties of atenolol tablets were evaluated.

Atenolol tablets were obtained by the Direct Compression method and using different excepients. After conducting some initial tests, tablets were subjected indifferent temperatures and humilities for six months. From different formulations, the atenolol release and disintegration time were analyzed. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) were used to determine the possible interactions between drug and excipients.

The results of drug release from different formulations after 3 and 6 months storage in 25°C/60% relative humidity (RH) and 40°C/75%RH showed significant differences among various times. Under all the storage conditions, atenolol tablets showed an increase in disintegration time. DSC and FTIR did not show any interaction.

The results of dissolution and disintegration time showed that keeping atenolol tablets for three or six months in different conditions caused significant changes in the drug release and disintegration. Moreover, no change was observed in the physical stability of tablets.

Background and

The gastroretentive drug delivery systems can be retained in the stomach due to low bulk density. This assist in improving the oral sustained delivery of drugs that have an absorption window in a particular region of the gastrointestinal tract. These systems release the drug content before reaching the absorption site and provide optimal bioavailability. Several approaches are currently utilized to prolong gastric retention time. These include floating systems, polymeric bioadhesive, and swelling and expanding systems. The objective of this study was to develop and characterize gastroretentive floating matrix tablets from propranolol HCl.

Propranolol floating matrix tablets, containing HPMC K15M or Carbopol and gas-generating agent were prepared using direct compression method. The drug release profile of tablets was evaluated based on USP method. The in vitro floating characteristics of these tablets were studied in pH 1.2.

The release rate decreased when the amount of polymer increased. The drug release also increased in the presence of gas-generating agent. The results showed that tablets containing HPMC had better floating properties than tablets containing Carbopol. Adding gas generating agent to the formulations modified the floating properties of matrices.

These results proved the effect of polymers and floating agents on drug release profile. The use of HPMC K15M and gas-generating agents can lead to suitable floating formulation of propranolol HCl.

Background and

Oral administrations have been used for many years as a main method comparing to other methods. Sustained release techniques have been a great interest recently. Matrix polymers are one of the ways used to prepare a sustained-release drug and are most widely used to prepare the controlled-release drugs. Cellulose derivatives are the most common ones. Solubilities of some drugs are pH-dependent due to their acidic or basic nature. Diltiazem Hydrochloride due to having a pH-dependent solubility is a suitable model to investigate the effect of pH and also to prepare pH-independent formulations.

In the present study, an attempt was made to form pH-independent formulations using HPMC, lactose, CAP and organic acids in different ratios. The physicochemical properties of tablets prepared (including weight uniformity, hardness, tensile strength, friability and assay) were investigated. Rate of drug release was studied using USP I at pH 1.2 and 7.2, and sampling was done in the time of 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, 8. The drug release data were analyzed according to four kinetics models.

Drug release profile in acid free formulations showed that it was higher in the acidic medium. 50% replacement of HPMC with CAP and 1:1 ratio with drug release was pH-independent. Studying the formulations containing organic acids citric acid and polymer with 1:1 and 2:1 ratios ascorbic acid and polymer with 1:1 and 2:1 ratios and tartaric acid with 1:1 and 2:1 ratios showed their pH independent release characteristics.

These results showed the effect of combination of polymers and organic acids on drug release and its kinetic. Thus, the micro-environmental conditions for the dissolution and diffusion of diltiazem HCl were almost kept constant. The release of diltiazem HCl from tablets composed of HPMC and organic acids was found to be pH-independent.