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G. V. Ramana Reddy ¹, S. Vidyadhara ², J. Ramesh Babu ², R. L. C. Sasidhar ², A. Ramu ²

Affiliations
1 Department of Biotechnology, Acharya Nagarjuna University, Nagarjuna Nagar, Guntur – 522 510, Andhra Pradesh, IN
2 Department of Pharmaceutics, Chebrolu Hanumaiah Institute of Pharmaceutical Sciences, Guntur - 522 019, Andhra Pradesh, IN

Abstract

Solid dispersions of lovastatin were formulated using pregelatinised starch (PGS) as super disintegrant and were further compressed into tablets by using various diluents such as lactose, dicalcium phosphate (DCP) and microcrystalline cellulose (MCC) to enhance the bioavailability. The solid dispersions were prepared by physical mixing, solvent evaporation and kneading methods. The solid dispersions were found to release the drug faster than the pure drug in dissolution media. The rapid release of poorly soluble lovastatin from solid dispersions was influenced by the proportion of polymer and the method employed for its preparation. Among the three methods employed solvent evaporation and kneading methods were found to be suitable for improving the dissolution rate of lovastatin. The release data was fitted to various kinetic models. The release was found to follow first order kinetics. Some of the dispersions prepared by the solvent evaporation method and kneading method were formulated into tablets with various diluents. The tablet preparations containing different diluents were found to release the drug in the order of DCP>MCC>Lactose. The dissolution rate of tablet formulations prepared with lovastatin solid dispersions (FK1, FS4) were found to release the drug at a faster rate than that of tablets prepared with plain drug.

Keywords

Lovastatin, Pregelatinised Starch, Solid Dispersions.

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S. Vidyadhara ¹, R. L. C. Sasidhar ¹, N. Ramya Krishna ¹, K. Sai Deepika ¹

Affiliations
1 Chebrolu Hanumaiah Institute of Pharmaceutical Sciences, Chowdavaram, Chandramoulipuram, Guntur – 522 019. Andhra Pradesh, IN

Abstract

Venlafaxine hydrochloride was formulated as oral controlled release matrix tablets using hydrophilic polymer such as hydroxypropyl methyl cellulose (HPMC K₁₅ M) along with electrolytes. In this work a new attempt was made for in situ interactions between drug and electrolytes were devised to control the release of highly water soluble drugs from oral hydrophilic monolithic systems. Electrolytes such as Calcium carbonate, magnesium trisilicate, sodium bicarbonate were used at different concentrations in various formulations, while drug and polymer concentrations were maintained constantly at 1:1 ratios in all the formulations. These electrolytes were used to monitor matrix swelling and gel properties. These findings indicated that the swelling and gel formation in the presence of ionizable species within the hydrophilic matrices provide an attractive alternative for controlled drug delivery from a simple monolithic system. FTIR studies were carried out for some selected formulations, which indicated that there were no interactions between drug and excipients used.

Keywords

Venlafaxine Hydrochloride, HPMC K₁₅M, Electrolytes, Controlled Release, Matrix Tablets.

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R. L. C. Sasidhar ¹, S. Vidyadhara ¹, N. T. Ramarao ², Y. Srinivasa Rao ³, K. Tejaswi ¹

Affiliations
1 Chebrolu Hanumaiah Institute of Pharmaceutical Sciences, Chandramoulipuram, Chowdavaram, Guntur-522 019 (A.P.), IN
2 Chebrolu Hanumaiah institute of Pharmaceutical sciences, Chandramoulipuram, Chowdavaram, Guntur-522 019 (A.P.), IN
3 Alkem Research Center, Industrial Estate, Opposite Talons Police Station, Navi Mumbai - 410 208, Maharashtra, IN
4 Vignan Institute of Pharmaceutical Technology, Duvvada, Visakhapatnam - 530 046, (A.P.), IN

Abstract

A simple, accurate and precise reverse phase high performance liquid chromatography (RPHPLC) method has been developed and validated for the simultaneous determination of aspirin and simvastatin in combined dosage form. Separation was performed on a C18 column [ODS column, 250mm × 4.5mm with particle size 5μm. with a mobile phase consisting of acetonitrile: methanol: phosphate buffer (55:30:15) at a flow rate of 1ml/min and UV detection was carried out at 225nm. The developed method was validated for the parameters like system suitability, specificity, linearity, accuracy and robustness according to the ICH guidelines Q2B. Retention times of aspirin and simvastatin were found to be 3.4 and 7.44 respectively. Linearity was found in the range from 10-50μg/mL for aspirin and 2-10μg/mL for simvastatin with correlation coefficients 0.9998 and 0.9999 respectively. The % recovery for 100% spiked level was 99.44 and 101.20 for aspirin and simvastatin respectively. The developed method was accurate, robust, selective, linear and repeatable which could be used for routine analysis of aspirin and simvastatin in their combined dosage forms.

Keywords

Aspirin, Simvastatin, Simultaneous, RP-HPLC.

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S. Vidyadhara ¹, R. L. C. Sasidhar ¹, B. Venkateswara Rao ¹, P. Ratna Kumari ¹

Affiliations
1 Chebrolu Hanumaiah Institute of Pharmaceutical Sciences, Chowdavaram, Guntur – 19, Andhra Pradesh, IN

Abstract

The aim of the present work is to develop a simple, accurate, precise and reproducible UV spectrophotometric method for the simultaneous determination of Tenofovir, Efavirenz and Lamivudine in bulk and pharmaceutical dosage form. The stock solutions of the standard drugs were prepared in methanol followed by the further required dilutions with distilled water. This method involves the formation and solving of simultaneous equations at 260nm, 347nm and 272 nm, as absorbance maxima of Tenofovir, Efavirenz and Lamivudine respectively. Beer's law obeyed the concentration range of 10 - 40mcg/mL, 5 - 20 mcg/mL and 5 - 20 mcg/mL for Tenofovir, Efavirenz and Lamivudine respectively. The results of analysis were validated statistically and by recovery studies. The % RSD for the recovery study was less than 2. The proposed method can be effectively used for the simultaneous estimation of these three drugs in bulk and combined tablet dosage form.

Keywords

Tenofovir, Efavirenz and Lamivudine, Simultaneous Equation Method, Method Validation.

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