Formulation of an HPMC gel drug reservoir system with ethanol-water as a solvent system and limonene as a penetration enhancer for enhancing in vitro transdermal delivery of nicorandil.

The objective of the present study was to formulate a hydroxypropyl methylcellulose (HPMC) gel drug reservoir system with ethanol-water as a solvent system and limonene as a penetration enhancer for enhancing the transdermal delivery of nicorandil so as to develop and fabricate a membrane-moderated transdermal therapeutic system (TTS). The in vitro permeation of nicorandil was determined across rat abdominal skin from a solvent system consisting of ethanol or various proportions of ethanol and water. The ethanol-water (70:30 v/v) solvent system that provided an optimal transdermal permeation was used in formulating an HPMC gel drug reservoir system with selected concentrations (0% w/w, 4% w/w, 6% w/w, 8% w/w or 10% w/w) of limonene as a penetration enhancer for further enhancement of transdermal permeation of nicorandil. The amount of nicorandil permeated in 24 h was found increased with an increase in the concentration of limonene in the drug reservoir system up to a concentration of 6% w/w, but beyond this concentration there was no further increase in the amount of drug permeated. The flux of nicorandil was 370.9 +/- 4.2 microg/cm2 x h from the drug reservoir system with 6% w/w of limonene, which is about 2.6 times the required flux to be obtained across rat abdominal skin for producing the desired plasma concentration for the predetermined period in humans. The results of a Fourier Transform Infrared study indicated that limonene enhanced the percutaneous permeation of nicorandil by partially extracting the stratum corneum lipids. It is concluded that the HPMC gel drug reservoir system prepared with a 70:30 v/v ethanol-water solvent system containing 6% w/w of limonene is useful in designing and fabricating a membrane-moderated TTS of nicorandil.

Clinical trials of ayurvedic formulations in the treatment of acne vulgaris.

Oral and externally used dermatological preparation for acne vulgaris employing herbal extracts have been developed and standardized, the herbal extracts used here were of the plants described in ayurvedic treatise like Bhavprakasha Nighantu and Charak Samhita. The efficacy of the treatment using the oral formulation with or without external preparation has been assessed through conduct of Phase II clinical trials in 53 patients for 4 weeks in a randomized, double-blind, placebo-controlled fashion and following Good Clinical Practices guidelines. The results were statistically analyzed and indicated that combination of use of internal and external preparation showed better efficacy as compared to the use of oral formulation alone.

Study of processing parameters influencing the properties of diltiazem hydrochloride microspheres.

Diltiazem hydrochloride-ethylcellulose microspheres were prepared by the water-in-oil emulsion-solvent evaporation technique. Small and spherical microspheres having a mean microsphere diameter in the range of 40-300 microm and entrapment efficiency of approximately 60-90% were obtained. Scanning electron micrographs of drug-loaded microspheres showed the presence of uniformly distributed small pores and absence of drug crystals on their surface, indicating simultaneous precipitation of drug and the polymer from the solvent during solvent evaporation. Differential scanning calorimetric analysis confirmed the absence of any drug-polymer interaction. The in vitro release profile could be altered significantly by changing various processing parameters to give a controlled release of drug from the microspheres. The stability studies of the drug-loaded microspheres showed that the drug was stable at storage temperatures, 5-55 degreesC, for 12 weeks.

Controlled-release isosorbide dinitrate pellets. Part I: Design and evaluation of controlled-release capsule dosage form.

Design and evaluation of 8-h controlled-release isosorbide dinitrate capsules representing 20.0 and 40.0 mg of the drug are described. The formulation conforms to the total drug incorporated in the dosage form. In vitro dissolution studies indicate that the formulations behave as controlled-release dosage forms. Studies of storage at 30 +/- 2 and 40 +/- 2 degrees C at relative humidities of 72.0 and 90.0%, respectively, indicate that both temperature and humidity accelerate the degradation of the formulation. These results indicate the need of controlled packaging conditions during manufacture of these capsules.

Controlled-release isosorbide dinitrate pellets. Part II: In vivo studies.

Isosorbide dinitrate (ISDN) capsules containing 20.0 and 40.0 mg of the drug (reported earlier in Part I of this series) were evaluated in vivo in eight healthy volunteers in a double-blind study with marketed sustained-release preparations containing 20.0 and 40.0 mg of ISDN. The results were normalized by administering placebo and four conventional ISDN tablets, each containing 5.0 mg of ISDN, to the same group of volunteers in a separate study. The blood pressure of the volunteers was monitored for 8 h. The results indicate that the capsules prepared in the laboratory with the new formulation gave controlled release when compared with the respective marketed SR product.

Biodegradable microspheres of poly(DL-lactic acid) containing piroxicam as a model drug for controlled release via the parenteral route.

Poly(DL-lactic acid), synthesized in this laboratory from DL-lactic acid, was used to prepare microspheres containing piroxicam, using a solvent evaporation technique. The microspheres obtained were characterized for their surface characteristics (by SEM), surface charge, density, particle size distribution, glass transition temperature, drug incorporation and encapsulation efficiency, IR spectroscopy and in vitro drug release. The suspension of microspheres was evaluated for its syringeability. The effect of channelling agents such as PVP and PEG 6000 on in vitro drug release was studied. The effect of gamma-radiation on poly(DL-lactic acid) and on the in vitro release of piroxicam from the microspheres was also studied.

Modified high-performance liquid chromatographic method for analysis of drotaverine in human plasma.

An HPLC method is described for the determination of drotaverine in plasma; papaverine is used as the internal standard. The lower limit of quantitation is 50 ng ml-1 with an inter-assay precision (RSD) of below 4%. The method has been validated and successfully used to assay clinical trial samples in healthy volunteers.

Effect of compressional forces on piroxicam polymorphs.

The effect of compressional force on the polymorphic transition in piroxicam has been examined, using pure polymorph, by differential scanning calorimetry, powder X-ray diffractometry and by determination of dissolution rates from tablets of the individual polymorphs. The needle shaped polymorph was found to undergo transition to the cubic polymorph during compression.

Drug targeting using non-magnetic and magnetic albumin-globulin mix microspheres of mefenamic acid.

Optimum conditions for the preparation of non-magnetic and magnetic microspheres of albumin-globulin mix (alglomix) containing mefenamic acid have been standardized. The effect of various parameters has been investigated with regard to the appearance, yield, drug content and encapsulation efficiency. The physicochemical parameters of the microspheres such as density, particle size distribution, surface topography and wall thickness, as well as the magnetite contained within the magnetic microspheres, have been determined. The infrared spectroscopic analysis confirmed the encapsulation of the drug and absence of free drug on the surface of the microspheres. The X-ray diffraction analysis confirmed that the crystallinity of the drug remained unchanged indicating thereby that no complex formation had taken place between core and coat materials. The in vitro release profiles of the microspheres have been studied. An attempt has also been made to check the in vivo efficacy in rats.

Naproxen parenteral formulation studies.

Naproxen sodium has been formulated in a parenteral dosage form. After a series of experiments involving solubility, pH, and excipient compatibility using Placket Burman experimental design, the formulation has been finalized. The accelerated stability studies on samples stored at high temperatures projected the shelf life to be 4.2 years. Toxicological, therapeutic efficacy, and other aspects of this formulation are being reported separately.